Name the most abundant element in the earth’s crust?
The most abundant element in earth’s crust is Oxygen. It is present in earth crust in form of oxide, carbonate etc. of metal.
What is the density of ice at its melting point?
The density of ice at its melting point is less than density of water. Ice have less density than water, that is why ice float on water.
Nanometer is an
A nanometer (nm) is a decimal fraction of the base SI unit of length, the meter, which is defined as the length of the path travelled by light in vacuum during a time interval of 1/299,792,458 of a second.
22 carat gold is
22 carat gold is a homogeneous mixture in which gold is mixed with small amount of copper or silver.
A Substance can be beaten into sheets and beaten into wires. What will you call it?
A substance that can be beaten into thin sheets and drawn into thin wire is both malleable and ductile. Gold is most malleable and ductile element.
Match the following with correct response.
Mixtures are one product of mechanically blending or mixing chemical substances such as elements and compounds, without chemical bonding or other chemical change, so that each ingredient substance retains its own chemical properties and makeup.
A chemical compound is a substance composed of two or more different elements chemically bonded together in a fixed proportion by mass. However, not all molecules are compounds. Compounds are pure substances that contain two or more elements combined in a definite fixed proportion.
Any substance that contains only one kind of an atom is known as an element. Because atoms cannot be created or destroyed in a chemical reaction, elements such as phosphorus (P4) or sulfur (S8) cannot be broken down into simpler substances by these reactions.
When a molecule is formed from elements of a different species it is a heteroatomic molecule. As an atom is the smallest particle of an element that retains the properties of that element, a molecule is the smallest particle of a compound.
The particle size of a substance ‘P’ present in water is 200 nm. What will be the nature of the solution expected?
The particle size of suspension is greater than 100 nm. So, particle size of substance ‘P’ present in water will be the suspension.
Two miscible liquids A and B are present in solution. The boiling point of A is 600C and that of B is 900C. Which of the following method is used to separate these two liquids?
Distillation is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation. Simple distillation is used when the boiling points of chemicals in a mixture having large differences (more than 25°C). Fractional distillation is used when the boiling points of chemicals in a mixture are close to each-other, usually within 77°F (25°C). Fractionating columns used to separate the mixtures.
What are the major constituents of universe?
The chemical composition of the Universe is dominated by the hydrogen and helium produced in the Big Bang. The remaining 90 or so chemical elements are produced in stars and constitute only a few percent of the overall mass. Astronomers refer to these elements (all except hydrogen and helium) as metals, even though this includes elements such as carbon and oxygen which are not considered metals in the normal sense.
Chemical composition of the Sun
Which of the following is incorrect about solubility-
A. It increases with increase in temperature
B. Mass of solute dissolution in 100 units of solvent
C. The solubility of common salt in water in 46g at 20∘c
D. It decreases with decrease in temperature
The correct answer is c as all the statements are false about the solubility.
An emulsion is a colloidal solution formed by mixing
An emulsion s a colloidal solution formed by mixing of two immiscible liquids.
Which method is applied to separate the colored material from flower petals?
The coloured material from flower petals can be separated by chromatography process. Chromatography is used to separate materials present in solution in vary trace amount
Which of the following element has the characteristics of both metals and non – etals?
The element that possesses characteristic of both metal and non-metal are called metalloid. Arsenic is the element that has properties of both metal and non-metal
Clouds and fogs are example of
Clouds and fogs are example of liquid in gas solution. Cloud is formed by combination of water vapour with dust particles. Fogs contain water vapour and gases.
When a beam of light is passed through a colloidal solution, it gets.
Scattering of beam of light when passes through a solution is called tyndall effect. Colloidal solution shows the tyndall effect and scatter the beam of light.
NH4Cl is separated from NaCl by which one of the following method.
NH4Cl is separated from NaCl by heating the solid mixture in a test tube. NH4Cl being sublime change into vapour which can be collected by cooling it. Nacl remain in test tube.
Which of the following has the smell of rotten egg?
Hydrogen sulfide gas produces an offensive "rotten egg" or "sulfur water" odor and taste in the water. In some cases, the odor may be noticeable only when the water is initially turned on or when hot water is run. Heat forces the gas into the air which may cause the odor to be especially offensive in a shower. Occasionally, a hot water heater is a source of hydrogen sulfide odor. The magnesium corrosion control rod present in many hot water heaters can chemically reduce naturally occurring sulfates to hydrogen sulfide.
Brass is a homogeneous mixture of
Brass is a homogenous mixture of 70% of Copper and 30% Zinc by mass. Copper and Zinc forms homogenous mixture as constituent particles are not visible
What is the name given to the liquid which contains in it some suspended particles?
The liquid which contains some suspended particles are called suspension. The size of particle is more than 100nm.
What will be the boiling point of water at the top of a mountain where the atmospheric pressure is less than 1 atm?
Boiling point of water decreases with increase in altitude. At the top of mountain where the atmospheric pressure is less than 1 atm water boils below 1000C.
Thermometer is an instrument that measures
Which of the following will be a heterogeneous mixture?
The mixture in which particles are not distributed evenly and forms separate layer if left undisturbed. The mixture of Albumin and water forms a heterogeneous mixture
Size of particles in a collided solution ranges from
The size of particles in colloidal solution ranges from 10−5cm to 10−7cm. less than 10−5 is true solution and more than 10−7 is suspension.
Match the following with correct response.
(a) The process of centrifugation is used in dairies to separate cream from milk. Centrifugation is a method for separating the suspended particles of a substance from a liquid in which the mixture is rotated at a high speed in a centrifuge machine.
(b) Oil being lighter forms the top layer, while water being heavier forms the bottom layer. Oil can be separated by decantation. However, a more useful method for separating oil and water is with the separating funnel.
(c) Chromatography is a technique used to separate the chemical compounds (pigments) of a mixture. One of the most common types is called paper chromatography.
(d) Air can be separated into its components of air through fractional distillation. In the fractional distillation process, the liquid air is distributed through the fractional distillation column. Here, the liquid air is permissible to warm-up. The liquid oxygen will be gathered in the fractionating column.
Brass is a solution of molten copper in
Brass is a solid solution consisting of zinc and other metals (solutes) dissolved in copper (solvent).