Question:
Name the technique to separate
(i) butter from curd
(ii) salt from sea-water
(iii) camphor from salt
Answer:
(i) butter from curd : centrifugation
(ii) salt from sea-water: evaporation followed by crystallization.
(iii) camphor from salt: sublimation
Is Matter Around Us Pure?
Q 1.
What is the general name of the process by which tea-leaves are separated from prepared tea ?
Q 2.
Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor
Q 3.
Choose one term from the following which includes the other three :
aerosol,
emulsion,
colloid,
sol
Q 4.
Name any two solid substances whose mixture can be separated by sublimation.
Q 5.
What are the physical states of dispersed phase and dispersion medium of a fog?
Q 6.
What are the properties of a colloid?
Q 7.
What are aqueous solutions?
Q 8.
What is saturated solution? Explain with an example.
Q 9.
What are the physical states of dispersed phase and dispersion medium of a cloud?
Q 10.
A solution contains 40 mL of ethyl alcohol mixed with 100mL of water. What is the concentration of the solution in terms of volume by volume percentage?
Q 11.
Define Brownian movement in colloids.
Q 12.
What are pure substances ? Give two examples of pure substances.
Q 13.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 14.
Name one pair of liquids which can be separated by using a separating funnel.
Q 15.
What is a solution? What are the properties of a solution?
Q 16.
How crystallization is better than evaporation?
Q 17.
Give two reasons for supposing that water is a compound and not a mixture.
Q 18.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 20.
What is meant by solute and solvent?
Q 21.
When we open the cap of a cola drink (or any carbonated beverage), why does excess of bubbles come out?
Q 22.
What are suspensions? Explain with an example.
Q 23.
To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293K. Find its concentration at this temperature.
Q 24.
What principle is applied in centrifugation? Give examples where this method is applied to separate mixtures.
Q 25.
Name the following :
(a) a lustrous liquid metal.
(b) a liquid non-metal
(c) a metal which can be cut with a knife
(d) a non-metal which is good conductor of electricity.
(e) an element which melts when kept on the palm.
(f) the best conductor of heat.
Q 26.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Q 27.
State the differences between compounds and mixtures.
Q 28.
What is an unsaturated solution?
Q 29.
What is Chromatography?
Q 30.
What is an emulsion? Give examples
Q 31.
What is the general name of the materials which contain at least two pure substances and show the properties of their constituents ?
Q 32.
(a) What is meant by a solution ? Give two examples of solutions.
(b)What is a suspension ? Give two examples of suspensions.
(c)
Q 33.
What are the characteristics exhibited by a pure substance?
Q 34.
On the basis of composition, how matter is classified?
Q 35.
Name two properties of a substance to check its purity?
Q 36.
What are the kinds of mixture?
Q 37.
What are non-aqueous solutions?
Q 38.
Explain with an example what is a colloid?
Q 39.
What are the reasons for separating the constituents of a mixture?
Q 40.
In beaker A, sugar cubes are dissolved into water while in beaker B, crushed cubes are taken. In which beaker the rate of dissolution is faster?
Q 41.
What are the differences and similarities between concentration and solubility?
Q 42.
Name a non-metal which is a good conductor of electricity.
Q 43.
Name the process you would use to separate a mixture of anthracene and copper sulphate ?
Q 44.
Name the source from which nitrogen and oxygen are obtained on a large scale.
Q 45.
Name one pair of substances whose mixture can be separated completely by distillation.
Q 46.
Which technique can be used to detect and identify traces of poison present in the stomach wash of a person ?
Q 47.
What are the characteristics of mixture?
Q 48.
List the points of differences between homogeneous and heterogeneous mixtures.
Q 49.
What are the constituents of brass?
Q 50.
What is a compound? Give an example.
