Question

A sealed glass jar has a small amount of water on the bottom. The rest of the volume in the jar is taken up by helium gas at a partial pressure of 526 mmHg, and water vapor. If the total pressure inside the jar is 760. mmHg, what is the temperature of the water?

Answer 1

Answer:

The temperature of the water is 70°C

Explanation:

Partial pressure of helium gas = 526 mmHg

Total pressure inside the jar= 760 mmHg

Suppose partial pressure of helium gas is $P_H_e$ and partial pressure of water is$P_H__2O$

And total pressure is $P_T$

As we know

$\mathrm{P}_{\mathrm{T}}=\mathrm{P}_{\mathrm{HE}}+\mathrm{P}_{\mathrm{H} 2 \mathrm{O}}$

Hence

Putting the values  

$760=526+\mathrm{P}_{\mathrm{H} 2 \mathrm{O}}$

$\mathrm{P}_{\mathrm{H} 2 \mathrm{O}}=760-526$

$\mathrm{P}_{\mathrm{H} 20}=234 \mathrm{mm} \mathrm{Hg}$

In bar,

$\mathrm{P}_{\mathrm{H} 2 \mathrm{O}}=234 \mathrm{mm} \mathrm{Hg} \times \frac{1.01325 \mathrm{bar}}{760 \mathrm{mm} \mathrm{Hg}}$

= 0.312 bar

 Now according to the steam table  

With the vapour pressure of water as 0.312 bar the temperature corresponds to 70°C