Q. 8.34

Calculate the final pressure, in atmospheres, for each of the following, if $V$ and $n$ do not change:

a. A gas with an initial pressure of $1.20 a t m$ at $75 ° C$ is cooled to $- 32 ° C .$

b. A sample of $N$ , with an initial pressure of $780 . m m H g$ at $- 75 ° C$ is heated to $28 ° C .$

Verified

Answer

The final pressure, in atmospheres, for each of the following :

a. $0.512 a t m$

b. $291.2 m m H g$

1Part(a) Step 1: Given information

We need to find that the final pressure, in atmospheres, if $V$ and $n$ do not change .

2Part(a) Step 2: Explanation

Here , we will use Gay-Lussac's law which says ;

We are given with , $P_{1} = 1.20 a t m, T_{2} = 32 ° C, T_{1} = 75 ° C$

$\frac{P_{1}}{T_{1}} = \frac{P_{2}}{T_{2}} \Rightarrow P_{2} = \frac{P_{1} \times T_{2}}{T_{1}} = \frac{1.20 \times (- 32)}{75} = 0.512 a t m$

3Part (b) Step 1: Given information

The final pressure, in atmospheres, if $V$ and $n$ do not change .

4Part(b) Step 2: Explanation

By using gay-lussac's law ;

We are given that ; $P_{1} = 780 m m H g, T_{2} = 28 ° C, T_{1} = - 75 ° C$

Substituting these values in given formula ;

$\frac{P_{1}}{T_{1}} = \frac{P_{2}}{T_{2}} \Rightarrow P_{2} = \frac{P_{1} \times T_{2}}{T_{1}} = \frac{780 \times (28)}{(- 75)} = 291.2 a t m$