Chapter 8, Problem 167IP

Interpretation Introduction

Interpretation:

• The density of a sample of gaseous thorium $\left(\text{IV}\right)$ fluoride has to be calculated.
• Rate of effusion of the gases thorium $\left(\text{IV}\right)$ fluoride and uranium $\left(\text{III}\right)$ fluoride has to be determined.

Concept introduction:

• Density is known as mass per unit volume. That is if the values of volume and mass of a substance is known its density can be calculated.

• The density of a solid sample remains constant whereas in gaseous sample it is not constant since the relative motion of gaseous molecules inside the container is not constant.

• Further gaseous molecules have weaker bond strength that its density is subjective to pressure and temperature.

• The density of a gaseous sample can be calculated by using ideal gas equation if temperature, pressure and number of moles of gaseous sample are known.

• Effusion is defined as the movement of gaseous molecules from the region of high concentration to low concentration.

• Gaseous molecules of low molar mass can effuse quickly.

• Rate of effusion of a gas is determined by Graham’s law of effusion which states

             “Rate of effusion of any gas is inversely proportional to the square root of its mass”

                       It can be expressed as $r\alpha \frac{1}{\sqrt{M}}$

                                where  ‘r’ stands for rate of effusion.

                                           ‘M’ stands for Molar mass.