Question

In a given process on an ideal gas dW = 0 and dQ < 0. What happens to the temperature of the gas.

Answer 1

We have 

dQ = du + dW 

We are give that dW = 0 and dQ < 0, so we can conclude that dU < 0 

Further for an ideal gas u T ∝ so that dT < 0. Which implies that the temperature of the gas decreases.