Chapter 10, Problem 121A

Interpretation Introduction

Interpretation:

The information provided by the formula for potassium chromate ( ${\text{K}}_{\text{2}}{\text{CrO}}_{\text{4}}$ ) should be determined.

Concept introduction:

A formula that represents a certain combination of elements present in a molecule is known as a molecular formula. In a molecular formula, the simpler number of every atom is present in a molecule.

Answer to Problem 121A

The molecular formula represents the number of atoms and the type of atoms present in the formula.

Value of molar mass is calculated by molecular formula of ${\text{K}}_{\text{2}}{\text{CrO}}_{\text{4}}$.

Explanation of Solution

The molecular formula of potassium chromate is ${\text{K}}_{\text{2}}{\text{CrO}}_{\text{4}}$.

Potassium chromate consists of three types of atoms that are potassium ( $\text{K}$ ), chromium ( $\text{Cr}$ ) and oxygen ( $\text{O}$ ).

The number of atoms present in the molecule is denoted by subscript.

According to the formula of potassium chromate that is ${\text{K}}_{\text{2}}{\text{CrO}}_{\text{4}}$, it contains two atoms of potassium, one atom of chromium and four atoms of oxygen.

With the help of the molecular formula of ${\text{K}}_{\text{2}}{\text{CrO}}_{\text{4}}$, the molar mass of the compound can be calculated.

Molar mass of potassium = 39.083 g/mole

Molar mass of chromium = 51.9961 g/mole

Molar mass of oxygen = 15.999 g/mole

Molar mass of ${\text{K}}_{\text{2}}{\text{CrO}}_{\text{4}}$ = $\text{2}\left(39.083\text{ g/mole}\right)+51.9961\text{ g/mole +4}\left(15.999\text{ g/mole}\right)$

= $194.1581\text{ g/mole}$

Thus, the value of molar mass is calculated by the molecular formula of ${\text{K}}_{\text{2}}{\text{CrO}}_{\text{4}}$.