Science Revision Test Physical and Chemical changes Class 7 1. what is difference between physical and chemical changes? 2.what is reversible and irreversible physical chamge A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour. 3.what kind of change is shown by Rusting of iron. (a) Lime water turns milky on passing carbon dioxide gas into it. (b) Bubbles are produced when acetic acid is added to a solution of sodium hydrogencarbonate 4. Lime water turns milky on passing carbon dioxide gas into it. 5. Bubbles are produced when acetic acid is added to a solution of sodium hydrogencarbonate. 6.A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour. (a) What changes do you expect? (b) Are these changes chemical in nature? (c) Write a word equation for the chemical change, if any 7.Give an example of a chemical reaction for each of the following s...