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All questions of Liquid State for Chemistry Exam
Select the correct statement(s).- a)Cohesive forces are the intermolecular forces between like molecules and adhesive forces are between unlike molecules
- b)A drop maintains its shape if cohesive forces are stronger than adhesive forces
- c)If cohesive forces are weak compared to adhesive forces, drop collapses and spreads into film
- d)Cohesive forces in mercury, consiste of metallic bonds between atoms, are strong; thus it does not wet glass
Correct answer is option 'A,B,C,D'. Can you explain this answer?
Select the correct statement(s).
a)
Cohesive forces are the intermolecular forces between like molecules and adhesive forces are between unlike molecules
b)
A drop maintains its shape if cohesive forces are stronger than adhesive forces
c)
If cohesive forces are weak compared to adhesive forces, drop collapses and spreads into film
d)
Cohesive forces in mercury, consiste of metallic bonds between atoms, are strong; thus it does not wet glass
|
Om Desai answered |
a) True, cohesive forces are intermolecular forces between like molecules and adhesive forces between unlike molecules.
b) True, only due to cohesive force, all the molecules of droplets(which are like molecule) are attracted towards each other to form drop
c) True, if the cohesive force becomes weak as to adhesive forces, then there will be no force to bind water molecules and the drop will collapse and spread into film.
d) True, It's only due to cohesive force that mercury doesn’t wet the glass.
b) True, only due to cohesive force, all the molecules of droplets(which are like molecule) are attracted towards each other to form drop
c) True, if the cohesive force becomes weak as to adhesive forces, then there will be no force to bind water molecules and the drop will collapse and spread into film.
d) True, It's only due to cohesive force that mercury doesn’t wet the glass.
Surface tension of water is 73 dynes cm -1 at 20° C. If surface area is increased by 0.10 m2, work done is- a)7.3 erg
- b)7.3 x 104 erg
- c)7.3 J
- d)0.73 J
Correct answer is option 'B'. Can you explain this answer?
Surface tension of water is 73 dynes cm -1 at 20° C. If surface area is increased by 0.10 m2, work done is
a)
7.3 erg
b)
7.3 x 104 erg
c)
7.3 J
d)
0.73 J
|
Lavanya Menon answered |
Work done = surface tension×Change in area
Surface tension = 73 dyne cm-1 or 73 x 10-3 N/m
Area = 0.10 m2
So, work done = 73×10-3 x 0.10
= 73 x 10-4 J or 73×10-4 x 107 erg
= 7.3×104 erg
Surface tension = 73 dyne cm-1 or 73 x 10-3 N/m
Area = 0.10 m2
So, work done = 73×10-3 x 0.10
= 73 x 10-4 J or 73×10-4 x 107 erg
= 7.3×104 erg
What is the boiling point of water?- a)100 °F
- b)671.67 °R
- c)373 °C
- d)212 °r
Correct answer is option 'B'. Can you explain this answer?
What is the boiling point of water?
a)
100 °F
b)
671.67 °R
c)
373 °C
d)
212 °r
|
Pioneer Academy answered |
°R represents the temperature measured on Rankine scale. Typically, boiling point of water is measured as 100 °C on the Celsius scale. The conversion of Celsius to Rankine scale is R = C x 9/5 + 491.67.
Considering boiling point of water as 100 °C, R = 100 x 9/5 + 491.67 = 671.67 °R
°F, °r represent the Fahrenheit and Reaumur scale, respectively.
Considering boiling point of water as 100 °C, R = 100 x 9/5 + 491.67 = 671.67 °R
°F, °r represent the Fahrenheit and Reaumur scale, respectively.
1 poise = ________.- a)0.1 kgm-1s-1
- b)1 kgm-1s-1
- c)10 kgm-1s-1
- d)100 kgm-1s-1
Correct answer is option 'A'. Can you explain this answer?
1 poise = ________.
a)
0.1 kgm-1s-1
b)
1 kgm-1s-1
c)
10 kgm-1s-1
d)
100 kgm-1s-1
|
|
Pioneer Academy answered |
Poise is the unit of viscosity. It’s S.I. unit is 1 Newton second per square meter. It’s Pascal second. In C.G.S. system, the unit of viscosity is poise that is named after a scientist Jean Louise
Poiseuille. So, it’s 1 poise = 0.1 kgm-1s-1.
Poiseuille. So, it’s 1 poise = 0.1 kgm-1s-1.
Which of the following properties of water can be used to explain the spherical shape of rain droplets?- a)Viscosity
- b)Surface tension
- c)Critical phenomenon
- d)Vapour pressure
Correct answer is option 'B'. Can you explain this answer?
Which of the following properties of water can be used to explain the spherical shape of rain droplets?
a)
Viscosity
b)
Surface tension
c)
Critical phenomenon
d)
Vapour pressure
|
Naina Bansal answered |
A simple way to form a drop is to allow liquid to flow slowly from the lower end of a vertical tube of small diameter. The surface tension of the liquid causes the liquid to hang from the tube, forming a pendant. When the drop exceeds a certain size it is no longer stable and detaches itself. The falling liquid is also a drop held together by surface tension.
Which of the following is caused by the addition of a non-volatile solute to a solvent?- a)Reduction in equilibrium of vapor pressure of solution
- b)Increase in melting point of the solution
- c)Decrease in the boiling point of the solution
- d)Osmosis of solute in the solution
Correct answer is option 'A'. Can you explain this answer?
Which of the following is caused by the addition of a non-volatile solute to a solvent?
a)
Reduction in equilibrium of vapor pressure of solution
b)
Increase in melting point of the solution
c)
Decrease in the boiling point of the solution
d)
Osmosis of solute in the solution
|
Vivek Khatri answered |
This phenomenon is known as ‘relative lowering of vapor pressure’ which is a very common colligative property. When a non-volatile solute is added to a solvent, the upper surface of the solvent is covered partially. Hence, the solvent molecules do not bear maximum freedom to escape into the space as vapors. Consequently, there is a decrease in vapor pressure when compared towhat it would have been with pure solvent and no solute at all.
Path in liquid in which layers do not meet each other is _______- a)laminar flow
- b)tubular flow
- c)viscosity
- d)straight path
Correct answer is option 'A'. Can you explain this answer?
Path in liquid in which layers do not meet each other is _______
a)
laminar flow
b)
tubular flow
c)
viscosity
d)
straight path
|
Hrishikesh Verma answered |
Laminar Flow
Laminar flow refers to the smooth and orderly movement of a fluid, where the layers of the fluid do not mix or meet each other. In this type of flow, the fluid particles move in parallel layers without any significant mixing or turbulence.
Characteristics of Laminar Flow
- Smooth and Streamlined: In laminar flow, the fluid flows in smooth and streamlined paths, with each layer of the fluid moving parallel to adjacent layers.
- No Mixing of Layers: The layers of the fluid do not mix or cross each other in laminar flow. Each layer maintains its distinct velocity and direction of flow.
- Low Turbulence: Laminar flow is characterized by low turbulence and minimal eddies or swirls in the fluid. The fluid particles move in a predictable and uniform manner.
Causes of Laminar Flow
Laminar flow is typically observed at low velocities and in fluids with low viscosity. Viscosity refers to the internal friction or resistance to flow within a fluid. When the viscosity of a fluid is high, it hinders the movement of fluid particles and promotes laminar flow.
Applications of Laminar Flow
Laminar flow has several practical applications in various fields, including:
- Chemical Engineering: Laminar flow is important in chemical engineering processes, such as the design and operation of pipelines, reactors, and heat exchangers.
- Medical Science: Laminar flow is utilized in medical settings to maintain sterile environments in operating rooms, laboratories, and cleanrooms. It helps to prevent the spread of contaminants and maintain a controlled airflow.
- Fluid Dynamics Research: Laminar flow is extensively studied in fluid dynamics research to understand the behavior and movement of fluids. It provides insights into fluid mechanics and helps in the development of models and theories.
Conclusion
In summary, laminar flow is the type of flow in which layers of a fluid move in a smooth and orderly manner without mixing or meeting each other. It is characterized by low turbulence and is observed at low velocities and in fluids with low viscosity. Laminar flow has various practical applications in industries and scientific research.
Laminar flow refers to the smooth and orderly movement of a fluid, where the layers of the fluid do not mix or meet each other. In this type of flow, the fluid particles move in parallel layers without any significant mixing or turbulence.
Characteristics of Laminar Flow
- Smooth and Streamlined: In laminar flow, the fluid flows in smooth and streamlined paths, with each layer of the fluid moving parallel to adjacent layers.
- No Mixing of Layers: The layers of the fluid do not mix or cross each other in laminar flow. Each layer maintains its distinct velocity and direction of flow.
- Low Turbulence: Laminar flow is characterized by low turbulence and minimal eddies or swirls in the fluid. The fluid particles move in a predictable and uniform manner.
Causes of Laminar Flow
Laminar flow is typically observed at low velocities and in fluids with low viscosity. Viscosity refers to the internal friction or resistance to flow within a fluid. When the viscosity of a fluid is high, it hinders the movement of fluid particles and promotes laminar flow.
Applications of Laminar Flow
Laminar flow has several practical applications in various fields, including:
- Chemical Engineering: Laminar flow is important in chemical engineering processes, such as the design and operation of pipelines, reactors, and heat exchangers.
- Medical Science: Laminar flow is utilized in medical settings to maintain sterile environments in operating rooms, laboratories, and cleanrooms. It helps to prevent the spread of contaminants and maintain a controlled airflow.
- Fluid Dynamics Research: Laminar flow is extensively studied in fluid dynamics research to understand the behavior and movement of fluids. It provides insights into fluid mechanics and helps in the development of models and theories.
Conclusion
In summary, laminar flow is the type of flow in which layers of a fluid move in a smooth and orderly manner without mixing or meeting each other. It is characterized by low turbulence and is observed at low velocities and in fluids with low viscosity. Laminar flow has various practical applications in industries and scientific research.
One of the following properties increase with increase in temperature,- a)Viscosity
- b)Surface tension
- c)Vapour pressure
- d)Density
Correct answer is option 'C'. Can you explain this answer?
One of the following properties increase with increase in temperature,
a)
Viscosity
b)
Surface tension
c)
Vapour pressure
d)
Density
|
|
Naina Bansal answered |
Vapor pressure or equilibrium vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature in a closed system. The equilibrium vapor pressure is an indication of a liquid's evaporation rate.
What does the vapor pressure of solvent containing a non-volatile solute, in a closed system directly vary with?- a)Mole fraction of solute
- b)Mole fraction of solvent
- c)Molarity of solute
- d)Molarity of solvent
Correct answer is option 'B'. Can you explain this answer?
What does the vapor pressure of solvent containing a non-volatile solute, in a closed system directly vary with?
a)
Mole fraction of solute
b)
Mole fraction of solvent
c)
Molarity of solute
d)
Molarity of solvent
|
Lekshmi Deshpande answered |
The vapor pressure of a solvent containing a non-volatile solute in a closed system directly varies with the mole fraction of the solvent. This phenomenon is explained by Raoult's law, which states that the vapor pressure of a solvent in a solution is proportional to its mole fraction in the solution.
Explanation:
1. Raoult's Law:
Raoult's law describes the relationship between the vapor pressure of a solvent in a solution and its mole fraction. According to this law, the partial pressure of a solvent in a solution is equal to the product of its vapor pressure in its pure state and its mole fraction in the solution.
2. Mole Fraction:
The mole fraction of a component in a solution is the ratio of the number of moles of that component to the total number of moles of all components in the solution. Mathematically, the mole fraction (X) is calculated as the moles of the component divided by the total moles in the solution.
3. Non-volatile Solute:
A non-volatile solute is a component that does not readily evaporate or escape from the solution. It remains in the liquid phase and does not significantly contribute to the vapor pressure of the solution.
4. Vapor Pressure and Mole Fraction of Solvent:
In a solution, the vapor pressure of the solvent is reduced by the presence of a non-volatile solute. The solute molecules occupy some of the space on the surface of the solvent, making fewer solvent molecules available to evaporate. Therefore, the vapor pressure of the solvent in the solution is lower than its pure state.
5. Relationship with Mole Fraction of Solvent:
The mole fraction of the solvent in the solution determines the extent to which the vapor pressure is reduced. As the mole fraction of the solvent increases, the number of solvent molecules at the surface of the solution increases, leading to a higher vapor pressure. Conversely, if the mole fraction of the solvent decreases, fewer solvent molecules are available at the surface, resulting in a lower vapor pressure.
6. Conclusion:
In summary, the vapor pressure of a solvent containing a non-volatile solute in a closed system directly varies with the mole fraction of the solvent. As the mole fraction of the solvent increases, the vapor pressure of the solvent in the solution also increases, according to Raoult's law.
Explanation:
1. Raoult's Law:
Raoult's law describes the relationship between the vapor pressure of a solvent in a solution and its mole fraction. According to this law, the partial pressure of a solvent in a solution is equal to the product of its vapor pressure in its pure state and its mole fraction in the solution.
2. Mole Fraction:
The mole fraction of a component in a solution is the ratio of the number of moles of that component to the total number of moles of all components in the solution. Mathematically, the mole fraction (X) is calculated as the moles of the component divided by the total moles in the solution.
3. Non-volatile Solute:
A non-volatile solute is a component that does not readily evaporate or escape from the solution. It remains in the liquid phase and does not significantly contribute to the vapor pressure of the solution.
4. Vapor Pressure and Mole Fraction of Solvent:
In a solution, the vapor pressure of the solvent is reduced by the presence of a non-volatile solute. The solute molecules occupy some of the space on the surface of the solvent, making fewer solvent molecules available to evaporate. Therefore, the vapor pressure of the solvent in the solution is lower than its pure state.
5. Relationship with Mole Fraction of Solvent:
The mole fraction of the solvent in the solution determines the extent to which the vapor pressure is reduced. As the mole fraction of the solvent increases, the number of solvent molecules at the surface of the solution increases, leading to a higher vapor pressure. Conversely, if the mole fraction of the solvent decreases, fewer solvent molecules are available at the surface, resulting in a lower vapor pressure.
6. Conclusion:
In summary, the vapor pressure of a solvent containing a non-volatile solute in a closed system directly varies with the mole fraction of the solvent. As the mole fraction of the solvent increases, the vapor pressure of the solvent in the solution also increases, according to Raoult's law.
Direction (Q. Nos. 10-12) This section contains 3 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONE or MORE THANT ONE is correct.Q. Select correct statement(s).- a)The water drop in vacuum is perfectly spherical
- b)The shape of water drop is distorted due to action of gravity
- c)Soaps and detergents drastically decrease the surface tension of water
- d)Due to increase in temperature, surface tension also increases and becomes maximum at critical temperature.
Correct answer is option 'A,B,C'. Can you explain this answer?
Direction (Q. Nos. 10-12) This section contains 3 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONE or MORE THANT ONE is correct.
Q. Select correct statement(s).
a)
The water drop in vacuum is perfectly spherical
b)
The shape of water drop is distorted due to action of gravity
c)
Soaps and detergents drastically decrease the surface tension of water
d)
Due to increase in temperature, surface tension also increases and becomes maximum at critical temperature.
|
Lead Academy answered |
The spherical shape is the shape in which it is most stable due to its surface tension. On earth also it is applicable. A drop of water wants to be in a spherical shape but is affected by other forces, so it becomes distorted. The shape is due to surface tension and not pressure. In space there is no force available to distort the spherical shape.
Adding soaps and detergents that disrupt the intermolecular attractions between adjacent water molecules can reduce the surface tension of water. Because they affect the surface properties of a liquid, soaps, and detergents are called surface-active agents, or surfactants.
Surface tension decreases when the temperature increases because cohesive forces decrease with an increase in molecular thermal activity.
Adding soaps and detergents that disrupt the intermolecular attractions between adjacent water molecules can reduce the surface tension of water. Because they affect the surface properties of a liquid, soaps, and detergents are called surface-active agents, or surfactants.
Surface tension decreases when the temperature increases because cohesive forces decrease with an increase in molecular thermal activity.
Direction (Q. Nos. 11-13) This section contains a paragraph, wach describing theory, experiments, data etc. three Questions related to paragraph have been given.Each question have only one correct answer among the four given options (a),(b),(c),(d).Variation of viscosity (q) with temperature T is given by 
Q. What is viscosity at 100 K?- a)2.0500
- b)0.3117
- c)1.0000
- d)1.0200
Correct answer is option 'B'. Can you explain this answer?
Direction (Q. Nos. 11-13) This section contains a paragraph, wach describing theory, experiments, data etc. three Questions related to paragraph have been given.Each question have only one correct answer among the four given options (a),(b),(c),(d).
Variation of viscosity (q) with temperature T is given by
Q. What is viscosity at 100 K?
a)
2.0500
b)
0.3117
c)
1.0000
d)
1.0200
|
Puja Pillai answered |
From the graph, we can see that;
log10 ƞ = 0.3010 + 1/T
= 0.3010 + 1/100 (at 100K) -------------(i)
Given that variation of viscosity(q) = log10ƞ with T
Therefore, log10 ƞ = 0.311
As only for log10 ƞ = 0.311, we will have eqn i correct
log10 ƞ = 0.3010 + 1/T
= 0.3010 + 1/100 (at 100K) -------------(i)
Given that variation of viscosity(q) = log10ƞ with T
Therefore, log10 ƞ = 0.311
As only for log10 ƞ = 0.311, we will have eqn i correct
Higher the viscosity, the slower the liquid flows.- a)True
- b)False
Correct answer is option 'A'. Can you explain this answer?
Higher the viscosity, the slower the liquid flows.
a)
True
b)
False
|
|
Vivek Khatri answered |
Viscosity is defined as the resistance to the flow of a liquid. It opposes a liquid’s layer movement with respect to one another. So, the above statement: the higher the viscosity, the slower the liquid flows is true.
If ethanol and chloroform are present in a molar ratio of 2:3 then what is the vapor pressure at 20° C if vapor pressures of pure liquids are 5.95 kPa and 21.17 kPa, respectively?- a)16.692 kPa
- b)15.082 kPa
- c)8.731 kPa
- d)12.038 kPa
Correct answer is option 'B'. Can you explain this answer?
If ethanol and chloroform are present in a molar ratio of 2:3 then what is the vapor pressure at 20° C if vapor pressures of pure liquids are 5.95 kPa and 21.17 kPa, respectively?
a)
16.692 kPa
b)
15.082 kPa
c)
8.731 kPa
d)
12.038 kPa
|
|
Vivek Khatri answered |
Given,
P0eth = 5.95 kPa
P0chl = 21.17 kPa
Mole ratio of ethanol ∶ chloroform = 2 ∶ 3
Total number of parts = 2 + 3 = 5
Therefore, mole fraction of ethanol, Xeth = 2/5 = 0.4
Mole fraction of chloroform, Xchl = 3/5 = 0.6
From Raoult’s law, pA = p0A x XA
Peth = 5.95 x 0.4 = 2.38 kPa
Pchl = 21.17 x 0.6 = 12.702 kPa
From Dalton’s law, Ptotal = Peth + Pchl
Ptotal = 2.38 + 12.702 = 15.082 kPa.
P0eth = 5.95 kPa
P0chl = 21.17 kPa
Mole ratio of ethanol ∶ chloroform = 2 ∶ 3
Total number of parts = 2 + 3 = 5
Therefore, mole fraction of ethanol, Xeth = 2/5 = 0.4
Mole fraction of chloroform, Xchl = 3/5 = 0.6
From Raoult’s law, pA = p0A x XA
Peth = 5.95 x 0.4 = 2.38 kPa
Pchl = 21.17 x 0.6 = 12.702 kPa
From Dalton’s law, Ptotal = Peth + Pchl
Ptotal = 2.38 + 12.702 = 15.082 kPa.
“Total pressure of gas mixture is the sum of individual pressures”. Which law is reflected in this statement?- a)Amagat’s law
- b)Raoult’s law
- c)Dalton’s law
- d)Henry’s law
Correct answer is option 'C'. Can you explain this answer?
“Total pressure of gas mixture is the sum of individual pressures”. Which law is reflected in this statement?
a)
Amagat’s law
b)
Raoult’s law
c)
Dalton’s law
d)
Henry’s law
|
|
Vivek Khatri answered |
Dalton’s of partial pressure states that for a non-reactive mixture of gases in a closed vessel, the total pressure of the mixture is the sum of pressures all individual gas components present. If gases A, B and C are present then, total pressure, Ptotal = PA + PB + PC.
Statement I : A certain amount of energy called activation energy (Ea) is required to move into a hole.Statement II : On increasing temperature, Ea is available and liquid can flow more easily thus, viscosity decreases.- a)Both Statement l and Statement II are correct and Statement Il is the correct explanation of Statement I
- b)Both Statement I and Statement II are correct and Statement II is not the correct explanation of Statement I
- c)Statement I is correct but Statement II is incorrect
- d)Statement II is correct but Statement I is incorrect
Correct answer is option 'A'. Can you explain this answer?
Statement I : A certain amount of energy called activation energy (Ea) is required to move into a hole.
Statement II : On increasing temperature, Ea is available and liquid can flow more easily thus, viscosity decreases.
a)
Both Statement l and Statement II are correct and Statement Il is the correct explanation of Statement I
b)
Both Statement I and Statement II are correct and Statement II is not the correct explanation of Statement I
c)
Statement I is correct but Statement II is incorrect
d)
Statement II is correct but Statement I is incorrect
|
Ashish Mishra answered |
A is correct.
What deviation is shown by a mixture of equimolar phenol and aniline?- a)Negative deviation
- b)Positive deviation
- c)No deviation
- d)Alternating positive and negative
Correct answer is option 'A'. Can you explain this answer?
What deviation is shown by a mixture of equimolar phenol and aniline?
a)
Negative deviation
b)
Positive deviation
c)
No deviation
d)
Alternating positive and negative
|
Sneha Menon answered |
Explanation:
When two liquids are mixed, the resulting mixture may show either positive or negative deviation from Raoult's law.
- Positive deviation: When the observed vapor pressure of the mixture is higher than the vapor pressure predicted by Raoult's law, the mixture shows positive deviation. This occurs when the intermolecular forces between unlike molecules are weaker than the forces between like molecules, resulting in a higher vapor pressure than expected.
- Negative deviation: When the observed vapor pressure of the mixture is lower than the vapor pressure predicted by Raoult's law, the mixture shows negative deviation. This occurs when the intermolecular forces between unlike molecules are stronger than the forces between like molecules, resulting in a lower vapor pressure than expected.
- No deviation: If the observed vapor pressure of the mixture is equal to the vapor pressure predicted by Raoult's law, the mixture shows no deviation.
In the case of equimolar phenol and aniline, the two molecules have similar molecular structures and can form hydrogen bonds with each other. The hydrogen bonding between phenol and aniline is stronger than the hydrogen bonding within each pure component, resulting in a lower vapor pressure than expected. Therefore, the mixture of equimolar phenol and aniline shows negative deviation from Raoult's law.
When two liquids are mixed, the resulting mixture may show either positive or negative deviation from Raoult's law.
- Positive deviation: When the observed vapor pressure of the mixture is higher than the vapor pressure predicted by Raoult's law, the mixture shows positive deviation. This occurs when the intermolecular forces between unlike molecules are weaker than the forces between like molecules, resulting in a higher vapor pressure than expected.
- Negative deviation: When the observed vapor pressure of the mixture is lower than the vapor pressure predicted by Raoult's law, the mixture shows negative deviation. This occurs when the intermolecular forces between unlike molecules are stronger than the forces between like molecules, resulting in a lower vapor pressure than expected.
- No deviation: If the observed vapor pressure of the mixture is equal to the vapor pressure predicted by Raoult's law, the mixture shows no deviation.
In the case of equimolar phenol and aniline, the two molecules have similar molecular structures and can form hydrogen bonds with each other. The hydrogen bonding between phenol and aniline is stronger than the hydrogen bonding within each pure component, resulting in a lower vapor pressure than expected. Therefore, the mixture of equimolar phenol and aniline shows negative deviation from Raoult's law.
A volatile liquid with vapor pressure 85 kPa (at sea level, 25° C) is taken to the peak of Mt. Everest. Which of the following is true?- a)The vapor pressure of the solution decreases
- b)The solution will condense quickly than when at sea level
- c)The solution will vaporize quickly than when at sea level
- d)The vapor pressure of the solution increases
Correct answer is option 'D'. Can you explain this answer?
A volatile liquid with vapor pressure 85 kPa (at sea level, 25° C) is taken to the peak of Mt. Everest. Which of the following is true?
a)
The vapor pressure of the solution decreases
b)
The solution will condense quickly than when at sea level
c)
The solution will vaporize quickly than when at sea level
d)
The vapor pressure of the solution increases
|
Stuti Patel answered |
°C) is placed in a closed container. The container is then heated to a temperature of 100°C. What will be the vapor pressure of the liquid at this new temperature?
To determine the vapor pressure of the liquid at the new temperature, we can use the Clausius-Clapeyron equation:
ln(P2/P1) = (ΔHvap/R) * (1/T1 - 1/T2)
Where:
P1 = initial vapor pressure (85 kPa)
P2 = final vapor pressure (unknown)
ΔHvap = enthalpy of vaporization
R = ideal gas constant (8.314 J/mol·K)
T1 = initial temperature (25+273 = 298 K)
T2 = final temperature (100+273 = 373 K)
First, let's calculate the value of ΔHvap for the liquid. This information is usually provided or can be looked up in a reference source. For this calculation, let's assume ΔHvap = 40 kJ/mol.
Substituting the known values into the equation:
ln(P2/85) = (40,000 J/mol / 8.314 J/mol·K) * (1/298 K - 1/373 K)
Simplifying:
ln(P2/85) = 4801.2 * (0.0034 - 0.0027)
ln(P2/85) = 4801.2 * 0.0007
ln(P2/85) = 3.36084
Using the property of logarithms, we can rewrite the equation as:
P2/85 = e^3.36084
Solving for P2:
P2 = 85 * e^3.36084
Using a scientific calculator or an online calculator, we find:
P2 ≈ 412.57 kPa
Therefore, the vapor pressure of the liquid at the new temperature of 100°C is approximately 412.57 kPa.
To determine the vapor pressure of the liquid at the new temperature, we can use the Clausius-Clapeyron equation:
ln(P2/P1) = (ΔHvap/R) * (1/T1 - 1/T2)
Where:
P1 = initial vapor pressure (85 kPa)
P2 = final vapor pressure (unknown)
ΔHvap = enthalpy of vaporization
R = ideal gas constant (8.314 J/mol·K)
T1 = initial temperature (25+273 = 298 K)
T2 = final temperature (100+273 = 373 K)
First, let's calculate the value of ΔHvap for the liquid. This information is usually provided or can be looked up in a reference source. For this calculation, let's assume ΔHvap = 40 kJ/mol.
Substituting the known values into the equation:
ln(P2/85) = (40,000 J/mol / 8.314 J/mol·K) * (1/298 K - 1/373 K)
Simplifying:
ln(P2/85) = 4801.2 * (0.0034 - 0.0027)
ln(P2/85) = 4801.2 * 0.0007
ln(P2/85) = 3.36084
Using the property of logarithms, we can rewrite the equation as:
P2/85 = e^3.36084
Solving for P2:
P2 = 85 * e^3.36084
Using a scientific calculator or an online calculator, we find:
P2 ≈ 412.57 kPa
Therefore, the vapor pressure of the liquid at the new temperature of 100°C is approximately 412.57 kPa.
Viscosity of liquid _________ with rise in temperature.
- a)Decreases
- b)Increases
- c)Remains constant
- d)Is independent
Correct answer is option 'A'. Can you explain this answer?
Viscosity of liquid _________ with rise in temperature.
a)
Decreases
b)
Increases
c)
Remains constant
d)
Is independent
|
|
Vivek Khatri answered |
As there is a rise in temperature the viscosity of liquid increases while the viscosity of gas decreases. In liquids, due to rise in temperature, molecules have high thermal energy so the can overcome intermolecular attractions.
Direction (Q. Nos. 9) Choice the correct combination of elements and column I and coloumn II are given as option (a), (b), (c) and (d), out of which ONE option is correct.Q. Match the physical properties given in Column I with the corresponding units given in Column II and select the correct answer from the codes given below.
- a)a
- b)b
- c)c
- d)d
Correct answer is option 'A'. Can you explain this answer?
Direction (Q. Nos. 9) Choice the correct combination of elements and column I and coloumn II are given as option (a), (b), (c) and (d), out of which ONE option is correct.
Q. Match the physical properties given in Column I with the corresponding units given in Column II and select the correct answer from the codes given below.
a)
a
b)
b
c)
c
d)
d
|
|
Ashish Mishra answered |
A is correct.
Consider the following statements.
1. The viscosity of a gas increases with rise in temperature.
2. The viscosity of the liquid falls very rapidly with rise in temperature.
Which of the statements(s) given above is/are correct?- a)Only 1
- b)Only 2
- c)Both 1 and 2
- d)Neither 1 nor 2
Correct answer is option 'C'. Can you explain this answer?
Consider the following statements.
1. The viscosity of a gas increases with rise in temperature.
2. The viscosity of the liquid falls very rapidly with rise in temperature.
Which of the statements(s) given above is/are correct?
1. The viscosity of a gas increases with rise in temperature.
2. The viscosity of the liquid falls very rapidly with rise in temperature.
Which of the statements(s) given above is/are correct?
a)
Only 1
b)
Only 2
c)
Both 1 and 2
d)
Neither 1 nor 2
|
Aarav Rane answered |
Understanding Viscosity in Gases and Liquids
Viscosity is a measure of a fluid's resistance to flow. It is influenced by temperature, and its behavior varies between gases and liquids.
1. Viscosity of Gases
- The viscosity of a gas increases with an increase in temperature.
- As temperature rises, gas molecules gain kinetic energy, leading to more frequent and intense collisions.
- This increased molecular activity results in a higher resistance to flow, hence a higher viscosity.
2. Viscosity of Liquids
- The viscosity of liquids behaves differently, typically decreasing with rising temperature.
- As temperature increases, the liquid molecules gain energy, which reduces the intermolecular forces holding them together.
- This reduction in cohesive forces allows the liquid to flow more freely, thus decreasing its viscosity.
Conclusion
Both statements correctly describe the behavior of viscosity in gases and liquids:
- Statement 1 is accurate: Viscosity of a gas increases with temperature.
- Statement 2 is also accurate: Viscosity of a liquid decreases with temperature.
Thus, the correct answer is option 'C', as both statements are correct. Understanding these principles is crucial for applications in various fields, including physics, engineering, and chemistry.
Viscosity is a measure of a fluid's resistance to flow. It is influenced by temperature, and its behavior varies between gases and liquids.
1. Viscosity of Gases
- The viscosity of a gas increases with an increase in temperature.
- As temperature rises, gas molecules gain kinetic energy, leading to more frequent and intense collisions.
- This increased molecular activity results in a higher resistance to flow, hence a higher viscosity.
2. Viscosity of Liquids
- The viscosity of liquids behaves differently, typically decreasing with rising temperature.
- As temperature increases, the liquid molecules gain energy, which reduces the intermolecular forces holding them together.
- This reduction in cohesive forces allows the liquid to flow more freely, thus decreasing its viscosity.
Conclusion
Both statements correctly describe the behavior of viscosity in gases and liquids:
- Statement 1 is accurate: Viscosity of a gas increases with temperature.
- Statement 2 is also accurate: Viscosity of a liquid decreases with temperature.
Thus, the correct answer is option 'C', as both statements are correct. Understanding these principles is crucial for applications in various fields, including physics, engineering, and chemistry.
If the angle of contact between the liquid and container is 90 degrees then? (C is the cohesive and A is the Adhesive force)- a)C > A
- b)C = A
- c)C < A
- d)C is not equal to A
Correct answer is option 'B'. Can you explain this answer?
If the angle of contact between the liquid and container is 90 degrees then? (C is the cohesive and A is the Adhesive force)
a)
C > A
b)
C = A
c)
C < A
d)
C is not equal to A
|
|
Maitri Sen answered |
If the angle of contact between the liquid and container is 90 degrees, it means that the cohesive force (C) and the adhesive force (A) are equal.
What is the boiling point at pressure 1 atm known as?
- a)Standard boiling point
- b)Van der Waal boiling point
- c)Normal boiling point
- d)Saturated boiling point
Correct answer is option 'C'. Can you explain this answer?
What is the boiling point at pressure 1 atm known as?
a)
Standard boiling point
b)
Van der Waal boiling point
c)
Normal boiling point
d)
Saturated boiling point
|
|
Vivek Khatri answered |
The boiling point at pressure 1 atm is known as normal boiling point. Normal boiling point is slightly greater than the standard boiling point as molecules change into the vapor phase and density of vapor increases.
Statement I : Liquids tend to have maximum number of molecules at their surface.
Statement II : Small liquid drops have spherical shape.
- a)Statement I is correct but Statement II is incorrect
- b)Both Statement I and Statement II are correct and Statement II is not the correct explanation of Statement I
- c)Both Statement l and Statement II are correct and Statement Il is the correct explanation of Statement I
- d)Statement II is correct but Statement I is incorrect
Correct answer is option 'B'. Can you explain this answer?
Statement I : Liquids tend to have maximum number of molecules at their surface.
Statement II : Small liquid drops have spherical shape.
Statement II : Small liquid drops have spherical shape.
a)
Statement I is correct but Statement II is incorrect
b)
Both Statement I and Statement II are correct and Statement II is not the correct explanation of Statement I
c)
Both Statement l and Statement II are correct and Statement Il is the correct explanation of Statement I
d)
Statement II is correct but Statement I is incorrect
|
Sanaya Menon answered |
Statement I: Liquids tend to have maximum number of molecules at their surface.
Statement II: Small liquid drops have spherical shape.
Explanation:
Statement I: Liquids tend to have maximum number of molecules at their surface.
This statement is correct. Liquids have a tendency to minimize their surface area due to intermolecular forces. The molecules at the surface of a liquid experience different forces compared to the molecules in the bulk of the liquid. The molecules in the bulk are surrounded by other molecules from all sides and are attracted equally in all directions. However, the molecules at the surface have unbalanced forces, as they are only attracted by the molecules below and around them. This leads to a net inward force, causing the liquid to minimize its surface area and form a droplet or spread out as a thin film.
Statement II: Small liquid drops have spherical shape.
This statement is also correct. When a liquid drop is small, the cohesive forces between its molecules dominate over the adhesive forces between the liquid and its surroundings. Cohesion refers to the attraction between molecules of the same substance, while adhesion refers to the attraction between molecules of different substances. The cohesive forces tend to pull the liquid molecules towards each other, resulting in a spherical shape. This is because a sphere has the minimum surface area for a given volume, allowing the liquid to minimize its surface energy.
Explanation of the relationship between the statements:
Both Statement I and Statement II are correct, but Statement II is not the correct explanation of Statement I. While both statements individually describe the behavior of liquids, they are not directly related to each other. Statement I explains the tendency of liquids to have a maximum number of molecules at their surface due to intermolecular forces, while Statement II describes the spherical shape of small liquid drops due to cohesive forces.
Therefore, the correct answer is option B: Both Statement I and Statement II are correct, and Statement II is not the correct explanation of Statement I.
Statement II: Small liquid drops have spherical shape.
Explanation:
Statement I: Liquids tend to have maximum number of molecules at their surface.
This statement is correct. Liquids have a tendency to minimize their surface area due to intermolecular forces. The molecules at the surface of a liquid experience different forces compared to the molecules in the bulk of the liquid. The molecules in the bulk are surrounded by other molecules from all sides and are attracted equally in all directions. However, the molecules at the surface have unbalanced forces, as they are only attracted by the molecules below and around them. This leads to a net inward force, causing the liquid to minimize its surface area and form a droplet or spread out as a thin film.
Statement II: Small liquid drops have spherical shape.
This statement is also correct. When a liquid drop is small, the cohesive forces between its molecules dominate over the adhesive forces between the liquid and its surroundings. Cohesion refers to the attraction between molecules of the same substance, while adhesion refers to the attraction between molecules of different substances. The cohesive forces tend to pull the liquid molecules towards each other, resulting in a spherical shape. This is because a sphere has the minimum surface area for a given volume, allowing the liquid to minimize its surface energy.
Explanation of the relationship between the statements:
Both Statement I and Statement II are correct, but Statement II is not the correct explanation of Statement I. While both statements individually describe the behavior of liquids, they are not directly related to each other. Statement I explains the tendency of liquids to have a maximum number of molecules at their surface due to intermolecular forces, while Statement II describes the spherical shape of small liquid drops due to cohesive forces.
Therefore, the correct answer is option B: Both Statement I and Statement II are correct, and Statement II is not the correct explanation of Statement I.
If a mixture of A and B boils at a temperature lower than the boiling point of either of the components, what kind of deviation does the mixture show?- a)No deviation
- b)Maximum and minimum deviation from Raoult’s law
- c)Negative deviation from Raoult’s law
- d)Positive deviation from Raoult’s law
Correct answer is option 'D'. Can you explain this answer?
If a mixture of A and B boils at a temperature lower than the boiling point of either of the components, what kind of deviation does the mixture show?
a)
No deviation
b)
Maximum and minimum deviation from Raoult’s law
c)
Negative deviation from Raoult’s law
d)
Positive deviation from Raoult’s law
|
|
Anshika Chavan answered |
B) Maximum and minimum deviation from Raoult
Considering a binary solution of components A and B obeys Raoult’s law, which of the following is true?- a)Total vapor pressure cannot be related to mole fraction of only one component
- b)Total vapor pressure of one component varies non-linearly with another component
- c)A plot of vapor pressures of both components gives a linear plot
- d)Total vapor pressure of solution always decreases with increase in mole fraction of a component
Correct answer is option 'C'. Can you explain this answer?
Considering a binary solution of components A and B obeys Raoult’s law, which of the following is true?
a)
Total vapor pressure cannot be related to mole fraction of only one component
b)
Total vapor pressure of one component varies non-linearly with another component
c)
A plot of vapor pressures of both components gives a linear plot
d)
Total vapor pressure of solution always decreases with increase in mole fraction of a component
|
|
Shruti Datta answered |
's law, which of the following statements is true?
A) The vapor pressure of the solution is equal to the sum of the vapor pressures of pure A and pure B.
B) The boiling point of the solution is higher than that of pure A and pure B.
C) The freezing point of the solution is lower than that of pure A and pure B.
D) The solubility of the solution is independent of temperature.
A) The vapor pressure of the solution is equal to the sum of the vapor pressures of pure A and pure B. This is the definition of Raoult's law, which states that the partial pressure of each component in a solution is proportional to its mole fraction in the solution. Therefore, the total vapor pressure of the solution is the sum of the partial pressures of A and B, which are equal to the vapor pressures of pure A and pure B, respectively.
B) The boiling point of the solution may be higher or lower than that of pure A and pure B, depending on the composition of the solution and the strength of the intermolecular forces between A and B molecules.
C) The freezing point of the solution may be higher or lower than that of pure A and pure B, depending on the composition of the solution and the strength of the intermolecular forces between A and B molecules.
D) The solubility of the solution may depend on temperature, especially if A and B have different temperature-dependent solubilities.
A) The vapor pressure of the solution is equal to the sum of the vapor pressures of pure A and pure B.
B) The boiling point of the solution is higher than that of pure A and pure B.
C) The freezing point of the solution is lower than that of pure A and pure B.
D) The solubility of the solution is independent of temperature.
A) The vapor pressure of the solution is equal to the sum of the vapor pressures of pure A and pure B. This is the definition of Raoult's law, which states that the partial pressure of each component in a solution is proportional to its mole fraction in the solution. Therefore, the total vapor pressure of the solution is the sum of the partial pressures of A and B, which are equal to the vapor pressures of pure A and pure B, respectively.
B) The boiling point of the solution may be higher or lower than that of pure A and pure B, depending on the composition of the solution and the strength of the intermolecular forces between A and B molecules.
C) The freezing point of the solution may be higher or lower than that of pure A and pure B, depending on the composition of the solution and the strength of the intermolecular forces between A and B molecules.
D) The solubility of the solution may depend on temperature, especially if A and B have different temperature-dependent solubilities.
In a liquid, the force required to maintain the flow of layers is 5N, velocity gradient in du/dx, area of contact is 20m2. Then what is the value of viscosity?- a)6.25 dz/du
- b)0.15 dz/du
- c)0.2 dz/du
- d)0.25 dz/du
Correct answer is option 'D'. Can you explain this answer?
In a liquid, the force required to maintain the flow of layers is 5N, velocity gradient in du/dx, area of contact is 20m2. Then what is the value of viscosity?
a)
6.25 dz/du
b)
0.15 dz/du
c)
0.2 dz/du
d)
0.25 dz/du
|
|
Jaya Sen answered |
Given:
Force required to maintain the flow of layers (F) = 5N
Velocity gradient (du/dx) = ?
Area of contact (A) = 20m²
Viscosity (η) is a measure of a fluid's resistance to flow. It is defined as the ratio of the shear stress (τ) to the velocity gradient (du/dx):
η = τ / (du/dx)
Shear stress (τ) can be calculated using the force (F) and the area of contact (A):
τ = F / A
Therefore, substituting the values:
τ = 5N / 20m²
τ = 0.25 N/m²
Now, substituting the value of shear stress (τ) into the equation for viscosity:
η = 0.25 N/m² / (du/dx)
Hence, the value of viscosity (η) is 0.25 dz/du (option D).
Force required to maintain the flow of layers (F) = 5N
Velocity gradient (du/dx) = ?
Area of contact (A) = 20m²
Viscosity (η) is a measure of a fluid's resistance to flow. It is defined as the ratio of the shear stress (τ) to the velocity gradient (du/dx):
η = τ / (du/dx)
Shear stress (τ) can be calculated using the force (F) and the area of contact (A):
τ = F / A
Therefore, substituting the values:
τ = 5N / 20m²
τ = 0.25 N/m²
Now, substituting the value of shear stress (τ) into the equation for viscosity:
η = 0.25 N/m² / (du/dx)
Hence, the value of viscosity (η) is 0.25 dz/du (option D).
The surface tension of liquid is _________ at critical temperature.
- a)one
- b)zero
- c)two
- d)three
Correct answer is option 'B'. Can you explain this answer?
The surface tension of liquid is _________ at critical temperature.
a)
one
b)
zero
c)
two
d)
three
|
|
Vivek Khatri answered |
The surface tension in liquids decreases with rise in temperature. As surface tension decreases, molecules become more active when temperature increases and surface tension becomes zero at critical temperature TC.
What phenomenon occurs when a solution’s equilibrium vapor pressure equals the surrounding atmospheric pressure?- a)Boiling
- b)Melting
- c)Condensation
- d)Sublimation
Correct answer is option 'A'. Can you explain this answer?
What phenomenon occurs when a solution’s equilibrium vapor pressure equals the surrounding atmospheric pressure?
a)
Boiling
b)
Melting
c)
Condensation
d)
Sublimation
|
|
Vivek Khatri answered |
Boiling, by definition, occurs when the vapor pressure of a liquid equals the surrounding atmospheric pressure. It is a very quick vaporization process which takes place at a constant temperature, referred to as the boiling point.
Statement I : As temperature is increased, less work is required to extend the surface of a liquid therefore surface tension decreases.Statement II : As the temperature and hence the intensity of molecular motion increases, intermolecular forces become less effective.- a)Both Statement l and Statement II are correct and Statement Il is the correct explanation of Statement I
- b)Both Statement I and Statement II are correct and Statement II is not the correct explanation of Statement I
- c)Statement I is correct but Statement II is incorrect
- d)Statement II is correct but Statement I is incorrect
Correct answer is option 'A'. Can you explain this answer?
Statement I : As temperature is increased, less work is required to extend the surface of a liquid therefore surface tension decreases.
Statement II : As the temperature and hence the intensity of molecular motion increases, intermolecular forces become less effective.
a)
Both Statement l and Statement II are correct and Statement Il is the correct explanation of Statement I
b)
Both Statement I and Statement II are correct and Statement II is not the correct explanation of Statement I
c)
Statement I is correct but Statement II is incorrect
d)
Statement II is correct but Statement I is incorrect
|
|
Ashish Mishra answered |
A is correct
How does the surface tension of a liquid vary with increase in temperature?- a)Remains same
- b)Decreases
- c)Increases
- d)No regular pattern is followed
Correct answer is option 'B'. Can you explain this answer?
How does the surface tension of a liquid vary with increase in temperature?
a)
Remains same
b)
Decreases
c)
Increases
d)
No regular pattern is followed
|
|
Naina Bansal answered |
In general, surface tension decreases when temperature increases because cohesive forces decrease with an increase of molecular thermal activity. The influence of the surrounding environment is due to the adhesive action liquid molecules have at the interface.
Statement I : Capillary action is due to surface tension.Statement II : Mercury, with its strong cohesive forces and weaker adhesive forces, does not show capillary rise.- a)Both Statement l and Statement II are correct and Statement Il is the correct explanation of Statement I
- b)Both Statement I and Statement II are correct and Statement II is not the correct explanation of Statement I
- c)Statement I is correct but Statement II is incorrect
- d)Statement II is correct but Statement I is incorrect
Correct answer is option 'B'. Can you explain this answer?
Statement I : Capillary action is due to surface tension.
Statement II : Mercury, with its strong cohesive forces and weaker adhesive forces, does not show capillary rise.
a)
Both Statement l and Statement II are correct and Statement Il is the correct explanation of Statement I
b)
Both Statement I and Statement II are correct and Statement II is not the correct explanation of Statement I
c)
Statement I is correct but Statement II is incorrect
d)
Statement II is correct but Statement I is incorrect
|
Debanshi Datta answered |
**Statement I : Capillary action is due to surface tension.**
Capillary action is the phenomenon where a liquid rises in a narrow tube or is drawn into a narrow space against the force of gravity. It occurs due to the combined effects of adhesive and cohesive forces.
**Statement II : Mercury, with its strong cohesive forces and weaker adhesive forces, does not show capillary rise.**
Mercury is a liquid metal with strong cohesive forces, meaning that its molecules have a strong attraction to each other. However, its adhesive forces, or the attraction between the molecules of mercury and the molecules of the container, are relatively weak. As a result, mercury does not show capillary rise in a narrow tube or space.
**Explanation:**
When a capillary tube is immersed in a liquid, the liquid rises or falls in the tube due to the balance between adhesive and cohesive forces. Adhesive forces are the attractive forces between the liquid molecules and the molecules of the container, while cohesive forces are the attractive forces between the liquid molecules themselves.
In the case of capillary rise, if the adhesive forces are greater than the cohesive forces, the liquid will rise in the tube. This is because the liquid molecules are more attracted to the molecules of the container than to each other, leading to a net upward force. The rise of the liquid is governed by the surface tension of the liquid, which is the force that holds the liquid molecules together at the surface.
Mercury, on the other hand, has strong cohesive forces due to its metallic nature. The cohesive forces between mercury molecules are much stronger than the adhesive forces between mercury and the container. As a result, the cohesive forces dominate and prevent capillary rise of mercury in a narrow tube. The surface tension of mercury is not sufficient to overcome the strong cohesive forces and allow it to rise in the tube.
Therefore, both Statement I and Statement II are correct. Statement II provides the correct explanation for why mercury does not show capillary rise.
Capillary action is the phenomenon where a liquid rises in a narrow tube or is drawn into a narrow space against the force of gravity. It occurs due to the combined effects of adhesive and cohesive forces.
**Statement II : Mercury, with its strong cohesive forces and weaker adhesive forces, does not show capillary rise.**
Mercury is a liquid metal with strong cohesive forces, meaning that its molecules have a strong attraction to each other. However, its adhesive forces, or the attraction between the molecules of mercury and the molecules of the container, are relatively weak. As a result, mercury does not show capillary rise in a narrow tube or space.
**Explanation:**
When a capillary tube is immersed in a liquid, the liquid rises or falls in the tube due to the balance between adhesive and cohesive forces. Adhesive forces are the attractive forces between the liquid molecules and the molecules of the container, while cohesive forces are the attractive forces between the liquid molecules themselves.
In the case of capillary rise, if the adhesive forces are greater than the cohesive forces, the liquid will rise in the tube. This is because the liquid molecules are more attracted to the molecules of the container than to each other, leading to a net upward force. The rise of the liquid is governed by the surface tension of the liquid, which is the force that holds the liquid molecules together at the surface.
Mercury, on the other hand, has strong cohesive forces due to its metallic nature. The cohesive forces between mercury molecules are much stronger than the adhesive forces between mercury and the container. As a result, the cohesive forces dominate and prevent capillary rise of mercury in a narrow tube. The surface tension of mercury is not sufficient to overcome the strong cohesive forces and allow it to rise in the tube.
Therefore, both Statement I and Statement II are correct. Statement II provides the correct explanation for why mercury does not show capillary rise.
A water drop is spherical in shape due to _______.- a)Viscosity
- b)Poise
- c)Surface tension
- d)Reflection
Correct answer is option 'C'. Can you explain this answer?
A water drop is spherical in shape due to _______.
a)
Viscosity
b)
Poise
c)
Surface tension
d)
Reflection
|
|
Vivek Khatri answered |
Surface Tension is the tendency of a fluid to occupy least surface area as possible. It is defined as the force per unit distance. So, the spherical shape that is acquired by a water drop is due to surface tension.
Some of the following properties of liquids arise because of the molecular interaction and thermal energy.
I. Vapour pressure II. Surface tension III. Viscosity Select the properties.- a)I and II
- b)I and III
- c)II and III
- d)I, II and III
Correct answer is option 'D'. Can you explain this answer?
Some of the following properties of liquids arise because of the molecular interaction and thermal energy.
I. Vapour pressure II. Surface tension III. Viscosity
I. Vapour pressure II. Surface tension III. Viscosity
Select the properties.
a)
I and II
b)
I and III
c)
II and III
d)
I, II and III
|
|
Ashish Mishra answered |
D is correct.
Arrange the following in increasing order of surface tension.I (water), II (ethanol), III (hexane)- a)I < II < III
- b)II < I < III
- c)Ill < I < II
- d)Ill < II < I
Correct answer is option 'D'. Can you explain this answer?
Arrange the following in increasing order of surface tension.
I (water), II (ethanol), III (hexane)
a)
I < II < III
b)
II < I < III
c)
Ill < I < II
d)
Ill < II < I
|
Preeti Iyer answered |
-Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension is what allows objects with a higher density than water such as razor blades and insects to float on a water surface without becoming even partly submerged
-D is the correct option.
What is S.I. unit of Surface Tension?- a)Dyne/meter
- b)Newton-meter
- c)Newton/meter
- d)Dyne-meter
Correct answer is option 'C'. Can you explain this answer?
What is S.I. unit of Surface Tension?
a)
Dyne/meter
b)
Newton-meter
c)
Newton/meter
d)
Dyne-meter
|
|
Vivek Khatri answered |
Surface Tension is the tendency of a fluid to occupy least surface area as possible. It is defined as the force per unit distance. So, the units of surface tension are Newton/meter in S.I. the system, Dyne/cm in C.G.S system.
The temperature dependence of the surface tension of a liquid is given by the Sugden equation,
.Select correct statement(s).- a)Surface tension approaches zero as critical temperature is attained, i.e. at T = TC
- b)Plot of log γ against log
is linear with a slope equal to n and an intercept equal to log γ0. - c)At reduced temperature equal to 1, surface disappears and γ = 0
- d)log γ decreases on increasing log
Correct answer is option 'A,B,C'. Can you explain this answer?
The temperature dependence of the surface tension of a liquid is given by the Sugden equation, .
.Select correct statement(s).
a)
Surface tension approaches zero as critical temperature is attained, i.e. at T = TC
b)
Plot of log γ against log is linear with a slope equal to n and an intercept equal to log γ0.
is linear with a slope equal to n and an intercept equal to log γ0.c)
At reduced temperature equal to 1, surface disappears and γ = 0
d)
log γ decreases on increasing log
|
|
T.ttttt answered |
(a) Surface tension of liquids generally decreases with temperatures. As temperature increases, the kinetic energy of molecules increases and they overcome the attractive forces.
(b) η of gases increase and η of liquids decrease with an increases in temperature.
As temperature increases, the average speed of molecules in a liquid also increase and as a result, they spend less time with their "neighbors." Therefore, as temperature increases, the average intermolecular forces decrease and the molecules are able to interact without being "weighed down" by one another. However, the viscosity of a gas increases as temperature increases because there is an increase in frequency of intermolecular collisions at higher temperatures. Since the molecules are flying around in the void most of the time, any increase in the contact they have with one another will increase the intermolecular force which will ultimately lead to a disability for the whole substance to move.
(c) For solids with elastic modulus of rigidity, the shearing force is proportional to Shear Strain
F=GϵA
For fluids, it is proportional to the rate of shear strain
F=μdydu
(b) η of gases increase and η of liquids decrease with an increases in temperature.
As temperature increases, the average speed of molecules in a liquid also increase and as a result, they spend less time with their "neighbors." Therefore, as temperature increases, the average intermolecular forces decrease and the molecules are able to interact without being "weighed down" by one another. However, the viscosity of a gas increases as temperature increases because there is an increase in frequency of intermolecular collisions at higher temperatures. Since the molecules are flying around in the void most of the time, any increase in the contact they have with one another will increase the intermolecular force which will ultimately lead to a disability for the whole substance to move.
(c) For solids with elastic modulus of rigidity, the shearing force is proportional to Shear Strain
F=GϵA
For fluids, it is proportional to the rate of shear strain
F=μdydu
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