## Work

$\Delta U=q+w$

sas_budge_1l
Posts: 10
Joined: Wed Sep 21, 2016 2:55 pm

### Work

If ΔT=0 and w=100J. ΔU = q+w =0 which means q= -w= -1000J.
Why does q=-1000 not q=0? because if ΔT=0 and you use the equation q=nCΔT wouldn't q=0 not q=-1000J?

Sunny Chera 1N
Posts: 20
Joined: Wed Sep 21, 2016 2:56 pm

### Re: Work

When delta U=0, in the case of isothermal expansion, the internal energy lost as work is replaced by heat. If heat were to be zero (q=0), then this would not be isothermal expansion. If a piston does 1000 J of work, then 1000 J of energy is replaced in the form of heat.