Question

What is the change in entropy of helium gas with total mass 0.135 kg at the normal boiling point of helium when it all condenses isothermally to liquid helium? Assume that the normal boiling point of helium is 4.216 K and the heat of vaporization of helium is 2.09×104 J/kg .

Answer 1

Answer:

-669.2 J/k

Explanation:

We are given that

Mass=m=0.135 kg

Normal boiling point,B.P=4.216 K

Heat f of vaporization=$H_v=-2.09\times 10^4 J/kg$

We have to find the change in entropy of helium gas.

$\Delta S=\frac{mH_v}{T}$

Using the formula then, we get

$\Delta S=\frac{0.135\times (-2.09\times 10^4}{4.216}$

$\Delta S=-669.2 J/K$

Hence, the change in entropy of helium gas=-669.2 J/k