The following data are obtained when dinitrogen and dioxygen react together to form different compounds:
Mass of dinitrogen Mass of dioxygen (i) 14 g 16 g (ii) 14 g 32 g (iii) 28 g 32 g (iv) 28 g 80 g
(a) Which law of chemical combination is obeyed by the above experimental data? Give its statement. (b) Fill in the blanks in the following conversions: (i) 1 km = ... mm = ... pm (ii) 1 mg = ... kg = ... ng (iii) 1 mL = ... L = ... dm³
The law of chemical combination obeyed by the given data is the Law of Multiple Proportions.
Statement: 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.
Explanation
To verify the law, we fix the mass of dinitrogen to 14 g. In case (i), 14 g of dinitrogen reacts with 16 g of dioxygen. In case (ii), 14 g of dinitrogen reacts with 32 g of dioxygen. In case (iii), 28 g of dinitrogen reacts with 32 g of dioxygen, which means 14 g of dinitrogen reacts with 16 g of dioxygen. In case (iv), 28 g of dinitrogen reacts with 80 g of dioxygen, which means 14 g of dinitrogen reacts with 40 g of dioxygen. The masses of dioxygen combining with a fixed mass (14 g) of dinitrogen are 16 g, 32 g, 16 g, and 40 g. These masses bear a simple ratio of 16:32:16:40, which simplifies to 2:4:2:5, confirming the Law of Multiple Proportions. For the unit conversions, standard metric prefixes are applied.