Question:
Why do fish go in deep waters during day light?
Answer:
During day time, the shallow water is warmer and hence it has less dissolved oxygen. Therefore fish tend to go in deep water during day time.
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.
Choose one term from the following which includes the other three :
aerosol,
emulsion,
colloid,
sol
Q 3.
Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor
Q 4.
What are the properties of a colloid?
Q 5.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Q 6.
What are the physical states of dispersed phase and dispersion medium of a cloud?
Q 7.
What are the physical states of dispersed phase and dispersion medium of a fog?
Q 8.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 9.
Name any two solid substances whose mixture can be separated by sublimation.
Q 10.
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 11.
Which of the following is a sol ?
Shaving cream,
Milk,
Fog,
Soap solution,
Hairspray
Q 12.
Which of the following will show Tyndall effect ? Why ?
(a) Salt solution
(b) Starch solution
(c)Milk
Q 13.
(a) What is meant by a solution ? Give two examples of solutions.
(b)What is a suspension ? Give two examples of suspensions.
(c)
Q 14.
List the points of differences between homogeneous and heterogeneous mixtures.
Q 15.
State the differences between compounds and mixtures.
Q 16.
What is meant by solute and solvent?
Q 17.
Describe sieving method.
Q 18.
Identify the following as mixture or compound.
(i) blood
(ii) common salt
(iii) sugar
(iv) brass
Q 19.
What is an emulsion? Give examples
Q 20.
Name a non-metal which is a good conductor of electricity.
Q 21.
Name the source from which nitrogen and oxygen are obtained on a large scale.
Q 22.
Which technique can be used to detect and identify traces of poison present in the stomach wash of a person ?
Q 23.
On the basis of composition, how matter is classified?
Q 24.
What are aqueous solutions?
Q 25.
What is an unsaturated solution?
Q 26.
What is saturated solution? Explain with an example.
Q 27.
What are suspensions? Explain with an example.
Q 28.
What are the properties of suspensions?
Q 29.
What do you mean by strength of the solution?
Q 30.
What are different ways to separate solid mixtures?
Q 31.
What are the reasons for separating the constituents of a mixture?
Q 32.
A good method to separate alum (phitkari) from impure samples is
(a) Filtration
(b) Sedimentaion
(c) Crystallization
(d) Sublimation
Q 33.
Define Brownian movement in colloids.
Q 34.
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 35.
Give examples of liquids that are
(i) completely miscible
(ii) partially miscible
(iii) practically immiscible
Q 36.
Which of the following is a mixture ?Salt, Air, Water, Alum, Sugar
Q 37.
Name the property :
(a) which allows metals to be hammered into thin sheets.
(b)
Q 38.
How much water should be mixed with 12 mL of alcohol so as to obtain 12 % alcohol solution ?
Q 39.
A 5 per cent sugar solution means that:
(a)5 g of sugar is dissolved in 95 g of water.
(b)5 g of sugar is dissolved in 100 g of water.
Choose the correct answer.
Q 40.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 41.
What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?
Q 42.
Name one pair of liquids which can be separated by using a separating funnel.
Q 43.
State whether the following statements are true or false :
(a) Alcohol can be separated from a mixture of alcohol and water by a separating funnel.
(b) Salt and water can be recovered from an aqueous salt solution by the process of evaporation.
Q 44.
What is meant by Solubility?
Q 45.
What principle is applied in centrifugation? Give examples where this method is applied to separate mixtures.
Q 46.
Who used the term 'element' first time?
Q 47.
What are the differences and similarities between concentration and solubility?
Q 48.
Name a metal which is soft and a non-metal which is hard.
Q 49.
Give two reasons for supposing that water is a compound and not a mixture.
Q 50.
(a) What is meant by (i) elements (ii) compounds, and (iii) mixtures ? Write down the names of two elements,two compounds and two mixtures.
(b) Classify the following into elements,
compounds and mixtures :
Marble,
Air,
Gold,
Brass,
Sand,
Diamond,
Graphite,
Petroleum,
Common salt,
Sea-water,
Chalk
