Question:
What factors affect the solubility of solvent and solute?
Answer:
- Temperature: For majority of solutions of solid-in-liquid and liquid-in-liquid types, solubility increases with temperature. However for solutions of gases-in-water type, solubility decreases with increase in temperature.
- Pressure: It is applicable to gas-in-liquid solutions. An increase in pressure increases the solubility of a gas. For example, aerated drinks contain carbon dioxide gas under pressure.
- Mechanical Stirring: Mechanical stirring increases solubility. For example, sugar dissolves faster on stirring with a spoon.
- Size of Solute Particles: Smaller the particle size of solute, greater is the solubility. For example, it is easier to dissolve powdered sugar than granules of sugar.
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.
Name one pair of liquids which can be separated by using a separating funnel.
Q 3.
Name one pair of substances whose mixture can be separated by fractional distillation.
Q 4.
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 5.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 6.
What are non-aqueous solutions?
Q 7.
How much water should be mixed with 12 mL of alcohol so as to obtain 12 % alcohol solution ?
Q 8.
Which technique can be used to detect and identify traces of poison present in the stomach wash of a person ?
Q 9.
How many elements are there which are in gaseous state at room temperature?
Q 10.
State whether the following statement is true or false : Milk is a pure substance.
Q 11.
Who used the term 'element' first time?
Q 13.
What is saturated solution? Explain with an example.
Q 14.
Calculate the mass of glucouse and mass of water required to make 200g of 25% solution of glucouse.
Q 15.
Name a non-metal which is a good conductor of electricity.
Q 16.
Define a compound. Give two points of evidence to show that sodium chloride is a compound.
Q 17.
How much water should be added to 15 grams of salt to obtain 15 per cent salt solution ?
Q 18.
Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor
Q 19.
What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?
Q 20.
Name the process which can be used to separate a mixture of salt solution and sand.
Q 21.
Name the apparatus you would use to separate oil from water.
Q 22.
What is a solution? What are the properties of a solution?
Q 23.
What are the advantages of preparing solutions?
Q 24.
What is an unsaturated solution?
Q 25.
What are the physical states of dispersed phase and dispersion medium of a fog?
Q 26.
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 27.
Name the elements are in liquid state at room temperature.
Q 28.
Why solutions do not exhibit Tyndall effect?
Q 29.
Which of the following is a mixture ?Salt, Air, Water, Alum, Sugar
Q 30.
What are pure substances ? Give two examples of pure substances.
Q 31.
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 32.
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.
Q 33.
Explain what happens when a beam of light is passed through a colloidal solution.
Q 34.
What is meant by the concentration of a solution ?
Q 35.
Name any two solid substances whose mixture can be separated by sublimation.
Q 36.
Name one pair of substances whose mixture can be separated completely by distillation.
Q 37.
How will you separate a mixture of chalk powder and water ?
Q 38.
Name the process which is used in milk dairies to separate cream from milk.
Q 39.
(a) Name the process by which common salt is obtained from sea-water.
(b) Name the process by which common salt is purified.
Q 40.
What are the kinds of mixture?
Q 41.
What are the characteristics of mixture?
Q 42.
What are suspensions? Explain with an example.
Q 43.
What do you mean by strength of the solution?
Q 44.
What are the various methods to express concentration of a solution?
Q 45.
What are different ways to separate solid mixtures?
Q 46.
What is an emulsion? Give examples
Q 47.
Name a metal which is soft and a non-metal which is hard.
Q 48.
Name the property :
(a) which allows metals to be hammered into thin sheets.
(b)
Q 49.
What is meant by saying that metals are malleable and ductile ?
Q 50.
The properties of the product are different from those of the constituents. State whether this statement best describes an element, a compound or a mixture.
