Question

When a system is taken from A to C through path ABC, 10 J of heat flows to the system and 4 J of work is done by the system.How much heat flows into the system in path ADC, if the work done by the system is 3 J?

Answer 1

$\frac{A\to B\to C}{△E_{AC}=q+\omega }=(+10)+(-4)=+6J$
$\frac{A\to D\to C}{\omega =-3J}$
$\therefore △E_{AC}=q-3$
Since E is a state function, both $△E$ must be same.
$\therefore 6=q-3$
$\therefore q=+9J$
Hence, 9 J flows into system.