Test: Matter In Our Surroundings - 2 - Class 9 MCQ

Option A ,B and D all shows the property possessed by matter hence C is incorrect.
Physical Properties of MatterColour, density, volume, mass, boiling temperature, and melting point are the six main physical properties. Shape, size, hardness, flexibility, texture, odour, temperature, volume, length, freezing point, electrical conductivity, and so on are some further examples.

Kelvin is the SI Unit of measurement of temperatures. It is represented with the Unit Kelvin 'K'.

Temperatures can be converted from Celsius to Kelvin by adding 273 to the Celsius Scale.

We have been given 3 temperatures here which are in the Celsius Scale.

25°C, 38°C and 66°C

To convert all of them to the Kelvin Scale, add 273 to all of them.

25 + 273 = 298 K
38 + 273 = 311 K
66 + 273 = 339 K

High pressure and low temperature allows the particle to come closer that compresses a liquid to form gas. 

Because liquid and gases have the tendency to flow.

The correct order of forces of attraction is:
- Air < Water < Sugar
Explanation:
- Air has the weakest forces of attraction among the options given.
- Water exhibits stronger forces of attraction compared to air due to hydrogen bonding.
- Sugar demonstrates the strongest forces of attraction in this sequence, likely due to its molecular structure and intermolecular forces.
This order reflects the varying degrees of intermolecular forces present in these substances, with sugar having the highest and air having the lowest.

Increase in temperature of water increases kinetic energy hence increases rate of evaporation.

Option A: Incorrect. Vaporisation refers to the conversion of a liquid into vapours, not directly from solid to vapours.
Option B: Correct. Sublimation is the process where a solid changes directly into vapours without passing through the liquid state.
Option C: Incorrect. Condensation is the process where vapours change into a liquid, not directly into a solid.
Option D: Incorrect. Fusion refers to the process of melting, where a solid changes into a liquid, not directly into vapours.

Evaporation ,diffusion and expansion of gases increase the temperature. Evaporation rate increases because of increasing temperature ,kinetic energy of molecules increases , so the molecules present at the surface of the liquid leave the surface quickly and go into the vapour state.

• Compressibility Increases: As a solid melts, its structure becomes less rigid, allowing the liquid to be compressed more easily.
• Interparticle Forces Decrease: In solids, particles are tightly packed with strong forces. When melting occurs, these forces weaken, allowing particles to move more freely.
• Kinetic Energy Increases: The heat energy added during melting causes particles to vibrate and move faster, leading to increased kinetic energy.

The heat  energy  required  to change  the state  of unit mass of  a substance  is called  latent  heat.  As the given solid is of unit mass  ( 1 kg)   and  we have  to change   its state into  liquid  , therefore  heat  needed will  be specific  latent heat of  fusion.

Sublimation is when a solid changes directly to gas without changing into liquid.
NaCl when heated does not change its state when heated , while all the other options sublime. Hence sodium chloride is the right answer.

• The SI unit of temperature is indeed kelvin, which measures thermal energy.
• The correct SI unit of pressure is Pascal, not Newton. Pascal measures force per unit area, while Newton measures force.
• Density is measured in kg/m³, which indicates mass per unit volume.
• One litre is equivalent to 1000 cm³ or 1 dm³, demonstrating the relationship between these volume measurements.

Any thing flows due to weaker intermolecular forces between them.