Chemistry Past Questions and Answers

If one mole of aluminium contains 6 x 10<sup style='font-size: smaller;'>23</sup> atoms of aluminium, how many atoms are contained in 0.9g of aluminium?<br/>(Al = 27)

4g each of aluminium foil and aluminium powder were introduced respectively into flasks P and Q.<br/>Flask P was treated with warm bench sodium hydroxide and all the aluminium dissolved in one hour. Flask Q was treated with cold sodium hydroxide and all the aluminium dissolved in 10 minutes. What was responsible for Q reacting faster than P?

What happens when the nitrates of potassium, calcium, zinc and copper are separately heated?

The scale formation in a kinetic used for boiling water is caused by the presence in water of?

An efflorescent compound is a substance that?