Question:
What are the advantages of preparing solutions?
Answer:
In a solution, solute and solvent may be present in the form of ions or molecules or both. Solutions are obtained for the following reasons:
- To carry out reactions. For a reaction to take place, reactant molecules must come close together. In solutions, reactions take place faster because reactants are in ionic or molecular form an dare close to each other.
- As dissolving medium like medicines. Certain medicines can only be administered to patients in solution form only. e.g. saline glucouse solution is given to patients suffering from dehydration.
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.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Q 5.
What are the properties of a colloid?
Q 6.
What are the physical states of dispersed phase and dispersion medium of a fog?
Q 7.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 8.
Name any two solid substances whose mixture can be separated by sublimation.
Q 9.
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 10.
What is meant by solute and solvent?
Q 11.
What are the physical states of dispersed phase and dispersion medium of a cloud?
Q 12.
Describe sieving method.
Q 13.
Name a non-metal which is a good conductor of electricity.
Q 14.
Which of the following is a sol ?
Shaving cream,
Milk,
Fog,
Soap solution,
Hairspray
Q 15.
Which of the following will show Tyndall effect ? Why ?
(a) Salt solution
(b) Starch solution
(c)Milk
Q 16.
(a) What is meant by a solution ? Give two examples of solutions.
(b)What is a suspension ? Give two examples of suspensions.
(c)
Q 17.
Name the source from which nitrogen and oxygen are obtained on a large scale.
Q 18.
On the basis of composition, how matter is classified?
Q 19.
What are aqueous solutions?
Q 20.
What is an unsaturated solution?
Q 21.
What are suspensions? Explain with an example.
Q 22.
What are the reasons for separating the constituents of a mixture?
Q 23.
Define Brownian movement in colloids.
Q 24.
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 25.
Identify the following as mixture or compound.
(i) blood
(ii) common salt
(iii) sugar
(iv) brass
Q 26.
Give examples of liquids that are
(i) completely miscible
(ii) partially miscible
(iii) practically immiscible
Q 27.
How much water should be mixed with 12 mL of alcohol so as to obtain 12 % alcohol solution ?
Q 28.
What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?
Q 29.
Name one pair of liquids which can be separated by using a separating funnel.
Q 30.
What is saturated solution? Explain with an example.
Q 31.
What are the properties of suspensions?
Q 32.
What principle is applied in centrifugation? Give examples where this method is applied to separate mixtures.
Q 33.
A good method to separate alum (phitkari) from impure samples is
(a) Filtration
(b) Sedimentaion
(c) Crystallization
(d) Sublimation
Q 34.
Who used the term 'element' first time?
Q 35.
What is an emulsion? Give examples
Q 36.
Name the property :
(a) which allows metals to be hammered into thin sheets.
(b)
Q 37.
(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
Q 38.
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 39.
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 40.
Name one pair of substances whose mixture can be separated completely by distillation.
Q 41.
Name the process which can be used to separate a mixture of salt solution and sand.
Q 42.
(a) Name the process by which common salt is obtained from sea-water.
(b) Name the process by which common salt is purified.
Q 43.
What are the characteristics exhibited by a pure substance?
Q 44.
What is meant by Solubility?
Q 45.
Why do fish go in deep waters during day light?
Q 46.
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 47.
How many elements are there which are in gaseous state at room temperature?
Q 48.
What are the differences and similarities between concentration and solubility?
Q 49.
Which of the following is a mixture ?Salt, Air, Water, Alum, Sugar
Q 50.
Fill in the following blanks :
(a)Milk is a.........solution but vinegar is a.......solution.
(b)A colloid is a........mixture and its components can be separated by the technique known as........
