Question

Calculate the internal energy change for the process in which $1.0kcal$ of heat is added to $1.2$ litre of $O_2$ gas in a cylinder at constant pressure of $1.0atm$ and the volume changes to $1.5litre$.

• A. $0.993kcal$
• B. $2.993kcal$
• C. $1.993kcal$
• D. $99.3kcal$

Answer 1

The correct option is A $0.993kcal$

In internal energy change,we have

$\Delta U=\Delta q-PdV$

$dV=1.5-1.2=0.3litre$

$\Delta U=1000-1\ast 0.3litre-atm$

$\Delta =1000-0.3\ast 24.2$

since, 1 litre-atm = 24.22cal

$\Delta U=-992.7calor-0.992kcal$