Question 1.TE.21: The following data were obtained when dinitrogen and dioxyge......

(a) Fixing the mass of dinitrogen as 14 g, the masses of dioxygen combined will be

16     :        32       :      16       :        40

or                  2     :          4       :      2        :         5

This is a simple whole number ratio and hence, the data illustrate the law of multiple proportions. The law of multiple proportions states that when two elements combine to form two or more than two compounds, then the mass of one of the elements which combine with a fixed mass of the other bear a simple whole number ratio.

(b) (i)

1 km = 1\ \text{km} \times \frac{1000\ \text{m}}{1\ \text{km}} \times \frac{100\ \text{cm}}{1\ \text{m}} \times \frac{10\ \text{mm}}{1\ \text{cm}} = 10^6 \text{mm}

1 km = 1 km \times\ \frac{1000\ \text{m}}{1\ \text{km}} \times \frac{1\ \text{pm}}{10^{-12}\ \text{m}} = 10^{15}\ \text{pm}

Correct answer : 10^6, 10^{15}

(ii) 1mg = 1mg \times\ \frac{1\ \text{g}}{1000\ \text{mg}} \times \frac{1\ \text{kg}}{1000\ \text{g}} = 10^{-6}\ \text{kg}

1 mg = 1 mg \times\ \frac{1\ \text{g}}{1000\ \text{mg}} \times \frac{1\ \text{ng}}{10^{-9}\ \text{g}} = 10^6\ \text{ng}

Correct answer : 10^{-6}, 10^{6}

(iii) 1 mL = 1mL \times\ \frac{1\ \text{L}}{1000\ \text{mL}} = 10^{-3}\ \text{L}

1 mL = 1 cm³ \times \left\lgroup \frac{1\ \text{dm}}{10\ \text{cm}} \right\rgroup^3 = 10^{-3}\ \text{dm}^3

Correct answer : 10^{-3}, 10^{-3}