The number of molecules in 4.25 g of ammonia is:

(a) 1.0 × 10²³

(b) 1.5 × 10²³

(c) 2.0 × 10²³

(d) 3.5 × 10²³

Correct the statements, if required

(a) One mole of chlorine contains 6.023 × 10²³ atoms of chlorine.

(b) Under similar conditions of temperature and pressure, two volumes of hydrogen combined with two volumes of oxygen will give two volumes of water vapour.

(c) Relative atomic mass of an element is the number of times one molecule of an element is heavier than $\dfrac{1}{12}$ the mass of an atom of carbon [C¹²].

(d) Under the same conditions of the temperature and pressure, equal volumes of all gases contain the same number of atoms.

Explain the terms empirical formula and molecular formula.

Give the empirical formula of:

(a) C₆H₆

(b) C₆H₁₈O₃

(c) C₂H₂

(d) CH₃COOH