The Total solution for NCERT class 6-12
The following data are obtained when dinitrogen anddioxygen react together to form different compounds:
Mass of dinitrogen Mass ofdioxygen
(i) 14g 16 g
(ii) 14g 32 g
(iii) 28 g 32 g
(iv) 28g 80 g
(a) Which law of chemical combination is obeyed by theabove 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
(a)
If we fix the mass of dinitrogen at 28 g, then the massesof dioxygen that will combine with the fixed mass of dinitrogen are 32 g, 64 g,32 g, and 80 g.
The masses of dioxygen bear a whole number ratio of1:2:2:5. Hence, the given experimental data obeys the law of multipleproportions. The law states that if two elements combine to form more than onecompound, then the masses of one element that combines with the fixed mass ofanother element are in the ratio of small whole numbers.
(b)
1 km = 106 mm
Hence, 1 km = 106 mm = 1015 pm
⇒ 1 mg = 10–6 kg
⇒ 1 mg = 106 ng
1 mg = 10–6 kg= 106 ng
⇒ 1 mL = 10–3 L
⇒ 1 mL = 10–3 dm3
1 mL = 10–3 L= 10–3 dm3