Answer
$28.57J/mol.K$
Work Step by Step
We can find the required $C_v$ for the gas as follows:
$C_v=\frac{\Delta E}{n\Delta T}$
We plug in the known values to obtain:
$C_v=\frac{1892-1492}{0.14\times (200-100)}$
$\implies C_v=28.57J/mol.K$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.