Kinetic Theory Of Gases Question 83
Question: Two moles of ideal helium gas are in a rubber balloon at $ 30{}^\circ C. $ The balloon is fully expandable and can be assumed to require no energy in its expansion. The temperature of the gas in the balloon is slowly changed to $ 35{}^\circ C. $ The amount of heat required in raising the temperature is nearly (take R = 8.31 J/mol. K)
Options:
A) 62 J
B) 104 J
C) 124 J
D) 208 J
Show Answer
Answer:
Correct Answer: D
Solution:
[d] The heat is supplied at constant pressure.
Therefore, $ Q=nC _{p}\Delta t $
$ =2[ \frac{5}{2}R ]\times \Delta t=2\times \frac{5}{2}\times 8.31\times 5=208J $
$ ( \
Therefore C _{p}=\frac{5}{2}R\text{ for mono-atomic gas} ) $