Question

Assume that a 2 kg of a certain gas with R=0.4305 kJ/kg-K undergoes a process that results in these changes: ΔU=1458.01 kJ, ΔH=2189.13 kJ. What is the value of cv?

Answer 1

$\triangle H= C_P\triangle T$

$\triangle U= C_V\triangle T$

Specific heat ratio, $k = \frac{C_p}{C_v} =\frac {\triangle H}{\triangle U}= \frac {2189.13}{1458.01}=1.49$

$C_p-C_v = R$ ​...(1)

$k = \frac{C_p}{C_v}$ ​...(2)

From 1 and 2

$R = 1.49C_v-C_v = 0.49C_v$

$C_v = \frac{0.4305}{0.49}=0.8785$ $\frac {kJ} {kg K}$