Chapter 3, Problem 143AP

Interpretation Introduction

Interpretation:

The empirical formula of lactic acid is to be determined with given mass of sample, carbon dioxide, and water.

Concept introduction:

Empirical formula is the simplest formula of any compound when written in the least possible whole number without altering the relative number of atoms.

The molecular mass of any compound is the sum of the atomic masses of every element that is present in the molecule of the compound. It is denoted by M. The unit of molecular mass isamu.

When any hydrocarbon has completely reacted with oxygen, then the product formed contains ${\text{CO}}_2$ and ${\text{H}}_2\text{O}$. In these products, the carbon and hydrogen come entirely from the hydrocarbon. The oxygen may come from the hydrocarbon if it contains any oxygen atom, but it primarily comes from the added oxygen.

Molar mass is calculated by adding masses of each and every element multiplied by their number of atoms (given in subscript). Its S.I. unit is $\text{g}/\text{mol}$.

The number of moles is defined as the ratio of mass to the molar mass:

$n=\frac{m}{M}$

Here, $n$ is the number of moles, $m$ is the mass, and $M$ is the molar mass.

The mass of compound can be calculated as $m=n\times M$.

Here, $n$ is the number of moles, $m$ is the mass, and $M$ is the molar mass.