Chapter 10, Problem 173A

Interpretation Introduction

Interpretation:

Empirical formula of the compound with 10.52 g Ni, 4.38 g C and 5.10 g N needs to be determined.

Concept introduction:

Empirical formula of a molecule is the smallest unit which is repeated in the molecule.

Answer to Problem 173A

The empirical formula is NiC₂N₂.

Explanation of Solution

Mass of Ni, C and N are 10.52 g, 4.38 g and 5.10 g respectively. The molar mass of Ni, C and N is 59 g/mol, 12 g/mol and 14 g/mol respectively.

The number of moles of each element can be calculated as follows:

Moles of Ni $\text{=}\frac{\text{10}\text{.52}}{59}\text{=0}\text{.178}\text{.}$

Moles of C $\text{=}\frac{\text{4}\text{.38}}{\text{12}}\text{=0}\text{.365}\text{.}$

Moles of N

$=\frac{5.10}{14}=\mathrm{0.364.}$

Smallest mole ratio Ni: C: N $\begin{array}{l}=\frac{0.178}{0.178}:\frac{0.365}{0.178}:\frac{0.364}{0.178}\\ =1:2.05:2.04\approx 1:2:2.\end{array}$

Thus, empirical formula is NiC₂N₂.

Conclusion

Empirical formula of the given compound is NiC₂N₂.