Calculate the molar masses of the following substances. Write the results with proper units.

(i) Ozone molecule, O₃

(ii) Ethanoic acid, CH₃COOH

If sulphur exists as S8 molecules, calculate the number of moles in 100 g of sulphur. (S = 32 u)

What is meant by the ‘molar mass’ of a substance? State the unit in which molar mass is usually expressed.

Which of the following pair of elements represents a mole ratio of 1 : 1?

Which of the following correctly represents 360 g water?

(i) 2 moles of H₂O

(ii) 20 moles 0f water

(iii) 6.022 × 10²³ molecules of water

(iv) 1.2044 × 10²⁵ molecules of water