$\begin{aligned}
& \mathrm{V}_1=800 \mathrm{cm}^3 \quad \mathrm{V}_2=200 \mathrm{cm}^3 \
& \mathrm{T}_1=300 \mathrm{~K}
\end{aligned}$
for adiabatic
$\begin{aligned}
& \mathrm{TV}^{\gamma-1}=\text { const. } \
& (300)(800)^{1.5-1}=\mathrm{T}_2(200)^{1.5-1} \
& \mathrm{T}_2=300\left[\frac{800}{200}\right]^{0.5}=300 \times\left(2^2\right)^{1 / 2} \
& \mathrm{T}_2=600 \mathrm{K} \
& \Delta \mathrm{T}=600-300=300 \mathrm{~K}
\end{aligned}$