Name two metals which are found in nature in the free state.

Define the following terms:
$(i)$ Mineral
$(ii)$ Ore
$(iii)$ Gangue

Write equations for the reactions of:
$(i)$ Iron with steam
$(ii)$ Calcium and potassium with water

Food cans are coated with tin and not with zinc because

You are given a hammer,a battery,a bulb,wires,and a switch.
$(a)$ How could you use them to distinguish between samples of metals and non-metals?
$(b)$ Assess the usefulness of these tests in distinguishing between metals and non-metals.

$A$ man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?