When a gas is heated, its internal energy increases by 600 J, while it has done work of 200 J.

When a gas is heated, its internal energy increases by 600 J, while it has done work of 200 J. What amount of heat has been given to the gas?

These tasks: ΔU (increase in the internal energy of the taken gas) = 600 J; A ‘(gas work) = 200 J.

To calculate the amount of heat imparted to the taken gas, we apply the first law of thermodynamics: ΔU = Q + A, whence Q = ΔU – A (A = -A ‘(Newton’s third law)) and the formula will take the form: Q = ΔU + A’.

Let’s calculate: Q = 600 + 200 = 800 J.

Answer: The taken gas was given 800 J of heat.