question_answer 62)

  Which of the following pairs have the same number of atoms? (a) \[16g\]of \[{{O}_{2}}(g)\]and \[4\,g\]of \[{{H}_{2}}(g)\] (b) \[16g\]of \[{{\text{O}}_{2}}\]and \[44\,g\]of \[C{{O}_{2}}\] (c) 28 g of \[{{N}_{2}}\] and 32 g of \[{{O}_{2}}\] (d) 12 g of C(s) and 23 g of Na(s)

Answer:

  (c, d) (c) Number of atoms of Nitrogen \[=\frac{\text{Mass}\,}{\text{Atomic}\,\text{mass}}\times 6.023\times {{10}^{23}}\] \[=\frac{28}{14}\times 6.023\times {{10}^{23}}\] \[=2\times 6.023\times {{10}^{23}}\] Number of atoms of Oxygen \[=\frac{32}{16}\times 6.023\times {{10}^{23}}\] \[=2\times 6.023\times {{10}^{23}}\] (d) Number of atoms of Carbon \[=\frac{12}{12}\times 6.023\times {{10}^{23}}\] \[=6.023\times {{10}^{23}}\] Number of atoms of Sodium \[=\frac{23}{23}\times 6.023\times {{10}^{23}}\]                 \[=6.023\times {{10}^{23}}\]