The following data are obtained when dinitrogen and dioxygen react together to form different compounds: Mass of dinitrogen Mass of dioxygen (i) 14g 16g (ii) 14g 32g (iii) 28g 32g (iv) 28g 80g (a) Which law of chemical combination is obeyed by the above experimental data?

(a) When the mass of dinitrogen is 28g, the mass of dioxygen combined is 32, 64, 32, and 80 g. The corresponding ratio is 1:2:1:5. It is a simple whole number ratio. This illustrates the law of multiple proportions. It states that, "if two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element, are in the ratio of small whole numbers (b) (i)1km=1000m × 100cm × 10mm ∴1km=10⁶mm 1km=1000m × 1pm/10⁻¹²m ∴1km=10¹⁵pm Hence, 1km=10⁶mm=10¹⁵pm (ii)1mg=10⁻³kg=10⁶ng (iii)1ml=10⁻³l=10⁻³dm³