Chapter 10.2, Problem 23SP

Interpretation Introduction

Interpretation: The density of the krypton gas at STP should be calculated.

Concept Introduction: Factor that uses one set of units to change it to another set of units is said to be a conversion factor.

Answer to Problem 23SP

The density of the krypton gas at STP is $\text{3}\text{.75 g/L}$ .

Explanation of Solution

The molar volume of any compound at STP is 22.4 L for 1 mol of the compound.

Now, using the value of the molar mass of the given compound and molar volume at STP, the density of the compound can be calculated.

The required conversion factor is:

  $\text{density}\left(\frac{\text{g}}{\text{L}}\right)\text{ = }\frac{\text{1 mol}}{\text{22}\text{.4 L}}\text{×molar mass (g/mol)}$

The molar mass of krypton is 84 g/mol.

On substituting the value of molar mass and solving:

  $\text{density}\left(\frac{\text{g}}{\text{L}}\right)\text{ = }\frac{\text{1 mol}}{\text{22}\text{.4 L}}\text{×}\frac{\text{84 g}}{1\text{ mol}}\text{ = 3}\text{.75 g/L}$

Hence, the density of the krypton gas at STP is $\text{3}\text{.75 g/L}$ .