Arrange the following in the order of increasing mass (atomic mass: O = 16, Cu = 63, N = 14)
I. one atom of oxygen
II. one atom of nitrogen
III. 1 × 10–10 mole of oxygen
IV. 1 × 10–10 mole of copper
(a) II < I < III < IV
(b) I < II < III < IV
(c) III < II < IV < I
(d) IV < II < III < I
Correct answer: (a) II < I < III < IV
Explanation:
Mass of 6.023 × 1023 atoms of oxygen = 16 g
Mass of one atom of oxygen
= \(\frac{16}{6.023 \times 10^{23}}\) = 2.66 x 10–23g
Mass of 6.023 × 1023 atoms of nitrogen
= 14 g
Mass of one atom of nitrogen
= \(\frac{14}{6.023 \times 10^{23}}\) = 2.32 x 10–23g
Mass of 1 mole of oxygen = 16 g
Mass of 1 × 10–10 mole of oxygen = 16 × 10–10
Mass of 1 mole of copper = 63 g
Mass of 1 × 10–10 mole of copper = 63 × 1 × 10–10
= 63 × 10–10
So, the order of increasing mass is II < I < III < IV