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.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 3.
Which of the following is a mixture ?Salt, Air, Water, Alum, Sugar
Q 4.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 5.
Name one pair of liquids which can be separated by using a separating funnel.
Q 6.
What is saturated solution? Explain with an example.
Q 7.
Calculate the mass of glucouse and mass of water required to make 200g of 25% solution of glucouse.
Q 8.
Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor
Q 9.
What are non-aqueous solutions?
Q 10.
How much water should be added to 15 grams of salt to obtain 15 per cent salt solution ?
Q 11.
Define Brownian movement in colloids.
Q 12.
Name the property :
(a) which allows metals to be hammered into thin sheets.
(b)
Q 13.
What is the concentration of a solution which contains 16 g of urea in 120 g of solution ?
Q 14.
What is meant by solute and solvent?
Q 15.
What are the physical states of dispersed phase and dispersion medium of a fog?
Q 16.
What is meant by saying that metals are malleable and ductile ?
Q 17.
What are pure substances ? Give two examples of pure substances.
Q 18.
Give two reasons for supposing that water is a compound and not a mixture.
Q 19.
Name the technique to separate
(i) butter from curd
(ii) salt from sea-water
(iii) camphor from salt
Q 20.
What is an emulsion? Give examples
Q 21.
Name a non-metal which is a good conductor of electricity.
Q 22.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Q 23.
Name the process which can be used to separate a mixture of salt solution and sand.
Q 24.
Name the apparatus you would use to separate oil from water.
Q 25.
What is a solution? What are the properties of a solution?
Q 26.
What is an unsaturated solution?
Q 27.
Name one pair of substances whose mixture can be separated by fractional distillation.
Q 28.
Name the source from which nitrogen and oxygen are obtained on a large scale.
Q 29.
State the differences between compounds and mixtures.
Q 30.
What principle is applied in centrifugation? Give examples where this method is applied to separate mixtures.
Q 31.
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 32.
What are different ways to separate solid mixtures?
Q 33.
What are the reasons for separating the constituents of a mixture?
Q 34.
(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 35.
Which of the following will show Tyndall effect ? Why ?
(a) Salt solution
(b) Starch solution
(c)Milk
Q 36.
What are the kinds of mixture?
Q 37.
What are the characteristics of mixture?
Q 38.
List the points of differences between homogeneous and heterogeneous mixtures.
Q 39.
What are aqueous solutions?
Q 40.
What is supersaturated solution?
Q 41.
What are the various methods to express concentration of a solution?
Q 42.
How crystallization is better than evaporation?
Q 43.
What is Chromatography?
Q 44.
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 45.
How many elements are there which are in gaseous state at room temperature?
Q 46.
Identify the following as mixture or compound.
(i) blood
(ii) common salt
(iii) sugar
(iv) brass
Q 47.
Give examples of liquids that are
(i) completely miscible
(ii) partially miscible
(iii) practically immiscible
Q 48.
State whether the following statement is true or false : Milk is a pure substance.
Q 49.
Name a metal which is soft and a non-metal which is hard.
Q 50.
A 15% alcohol solution means :
(a)15 mL alcohol and 85 mL water.
(b)15 mL alcohol and 100 mL water.
Choose the correct answer.
