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.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 3.
How much water should be added to 15 grams of salt to obtain 15 per cent salt solution ?
Q 4.
Name one pair of substances whose mixture can be separated by fractional distillation.
Q 5.
Name one pair of liquids which can be separated by using a separating funnel.
Q 6.
Define Brownian movement in colloids.
Q 7.
What is saturated solution? Explain with an example.
Q 8.
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 9.
What is the concentration of a solution which contains 16 g of urea in 120 g of solution ?
Q 10.
What is an unsaturated solution?
Q 11.
Name the elements are in liquid state at room temperature.
Q 12.
Who used the term 'element' first time?
Q 13.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Q 14.
Name the process which can be used to separate a mixture of salt solution and sand.
Q 15.
Calculate the mass of glucouse and mass of water required to make 200g of 25% solution of glucouse.
Q 16.
Identify the following as mixture or compound.
(i) blood
(ii) common salt
(iii) sugar
(iv) brass
Q 17.
Name a non-metal which is a good conductor of electricity.
Q 18.
Name the property :
(a) which allows metals to be hammered into thin sheets.
(b)
Q 19.
Give two reasons for supposing that water is a compound and not a mixture.
Q 20.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 21.
What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?
Q 22.
What are non-aqueous solutions?
Q 23.
Explain with an example what is a colloid?
Q 24.
How are sol, solution and suspension different from each other?
Q 25.
Give examples of liquids that are
(i) completely miscible
(ii) partially miscible
(iii) practically immiscible
Q 26.
Name a metal which is soft and a non-metal which is hard.
Q 27.
What is meant by saying that metals are malleable and ductile ?
Q 28.
What are different categories of pure substance?
Q 30.
State the differences between compounds and mixtures.
Q 31.
How crystallization is better than evaporation?
Q 32.
What is an emulsion? Give examples
Q 33.
What are the differences and similarities between concentration and solubility?
Q 34.
Is air a mixture or a compound ? Give three reasons for your answer.
Q 35.
Name a metal :
(a) which can be easily cut with a knife
(b) which forms amalgams
©which has not fixed shape
(d) which has a low melting point
(e) which is yellow in colour
Q 36.
Which of the two will scatter light: soap solution or sugar solution ? Why ?
Q 37.
Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor
Q 38.
Name the process which is used in milk dairies to separate cream from milk.
Q 39.
Which technique can be used to detect and identify traces of poison present in the stomach wash of a person ?
Q 40.
Name two properties of a substance to check its purity?
Q 41.
What are the kinds of mixture?
Q 42.
What is meant by solute and solvent?
Q 43.
What is meant by Solubility?
Q 44.
Based on the type of solvent, how solutions are classified?
Q 45.
What are the advantages of preparing solutions?
Q 46.
What are the physical states of dispersed phase and dispersion medium of a cloud?
Q 47.
What is Chromatography?
Q 48.
Why solutions do not exhibit Tyndall effect?
Q 49.
State whether the following statement is true or false : Milk is a pure substance.
Q 50.
Which of the following is a mixture ?Salt, Air, Water, Alum, Sugar
