Chapter 10, Problem 130A

Interpretation Introduction

Interpretation:

The molecular formula of the compound should be determined along with its molar mass.

Concept introduction:

The number of moles of a compound is defined as the ratio of the given mass of the compound to the molar or molecular mass of the compound.

The mathematical expression is given by:

Number of moles = $\frac{\text{given mass of the compound}}{\text{molar mass of the compound}}$

The one mole of any substance is equal to the Avogadro number i.e. $6.022\times {10}^{23}$ atoms.

Answer to Problem 130A

The molecular formula of the compound = $\text{Ca}{\left({\text{C}}_2{\text{H}}_3{\text{O}}_2\right)}_2$

The molar mass of $\text{Ca}{\left({\text{C}}_2{\text{H}}_3{\text{O}}_2\right)}_2$ = $158.164\text{ g/mole}$

Explanation of Solution

Given graph:

According to the given graph, one atom of calcium, four atoms of carbon, six atoms of hydrogen and four atoms of oxygen are present. Thus, the molecular formula of the compound is ${\text{CaC}}_{\text{4}}{\text{H}}_{\text{6}}{\text{O}}_{\text{4}}$ or $\text{Ca}{\left({\text{C}}_2{\text{H}}_3{\text{O}}_2\right)}_2$.

Molar mass of calcium = 40.078 g/mole

Molar mass of carbon = 12.0107 g/mole

Molar mass of hydrogen = 1.00784 g/mole

Molar mass of oxygen = 15.999 g/mole

Molar mass of $\text{Ca}{\left({\text{C}}_2{\text{H}}_3{\text{O}}_2\right)}_2$

= $\text{1}\times \text{40}\text{.078 g/mole +4}\left(12.0107\text{ g/mole}\right)+6\left(1.00784\text{ g/mole}\right)+4\left(15.999\text{ g/mole}\right)$

= $158.164\text{ g/mole}$