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.
What are the physical states of dispersed phase and dispersion medium of a fog?
Q 4.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 5.
What is meant by solute and solvent?
Q 6.
Name one pair of liquids which can be separated by using a separating funnel.
Q 7.
Name one pair of substances whose mixture can be separated by fractional distillation.
Q 8.
What is a solution? What are the properties of a solution?
Q 9.
What are non-aqueous solutions?
Q 10.
What is saturated solution? Explain with an example.
Q 11.
Which of the following is a mixture ?Salt, Air, Water, Alum, Sugar
Q 12.
Name the property :
(a) which allows metals to be hammered into thin sheets.
(b)
Q 13.
How much water should be added to 15 grams of salt to obtain 15 per cent salt solution ?
Q 14.
Name the source from which nitrogen and oxygen are obtained on a large scale.
Q 15.
Name the apparatus you would use to separate oil from water.
Q 16.
What is an unsaturated solution?
Q 17.
What are the various methods to express concentration of a solution?
Q 18.
Calculate the mass of glucouse and mass of water required to make 200g of 25% solution of glucouse.
Q 19.
Name the technique to separate
(i) butter from curd
(ii) salt from sea-water
(iii) camphor from salt
Q 20.
What are the differences and similarities between concentration and solubility?
Q 21.
Define Brownian movement in colloids.
Q 22.
State whether the following statement is true or false : Milk is a pure substance.
Q 23.
Name a metal which is soft and a non-metal which is hard.
Q 24.
Name a non-metal which is a good conductor of electricity.
Q 25.
What is meant by saying that metals are malleable and ductile ?
Q 26.
What are pure substances ? Give two examples of pure substances.
Q 27.
Give two reasons for supposing that water is a compound and not a mixture.
Q 28.
How much water should be mixed with 12 mL of alcohol so as to obtain 12 % alcohol solution ?
Q 29.
Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor
Q 30.
Name one pair of substances whose mixture can be separated completely by distillation.
Q 31.
Which technique can be used to detect and identify traces of poison present in the stomach wash of a person ?
Q 32.
What is Chromatography?
Q 33.
Name the elements are in liquid state at room temperature.
Q 34.
Why solutions do not exhibit Tyndall effect?
Q 35.
Name the process which can be used to separate a mixture of salt solution and sand.
Q 36.
What are the kinds of mixture?
Q 37.
List the points of differences between homogeneous and heterogeneous mixtures.
Q 38.
Why do fish go in deep waters during day light?
Q 39.
How crystallization is better than evaporation?
Q 40.
Who gave the first explanatory definition of 'element'?
Q 41.
Choose one term from the following which includes the other three :
aerosol,
emulsion,
colloid,
sol
Q 42.
Which of the following will show Tyndall effect ? Why ?
(a) Salt solution
(b) Starch solution
(c)Milk
Q 43.
What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?
Q 44.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Q 45.
What are different categories of pure substance?
Q 46.
What are suspensions? Explain with an example.
Q 47.
What are the properties of suspensions?
Q 48.
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 49.
How many elements are there which are in gaseous state at room temperature?
Q 50.
Who used the term 'element' first time?
