What do you understand by the statement “the solubility of copper sulphate in water at 20°C is 20.7 g’?

Which of the following are chemical changes and which physical? Give reason.

(i) a glass bottle breaking

(ii) coal burning in air

(iii) making a cake

(iv) wool being knitted into a sweater

(a) Define solubility of a substance. How does it vary with temperature?

What is the effect of temperature on the solubility of solids in liquids?

What is meant by a solution? Give two examples of solutions.