question 4/5?

Question

One mole of an ideal gas is heated for Δ T = 74 K in an isobaric process. During the process the gas absorbed Q = 1,689 J of heat. Calculate the change of its internal energy. Enter your answer in scientific notation with 3 sig. fig.

Answer 1

Please understand that the heat Q absorbed by the gas is for increasing the internal energy as well as doing work on the environment. Once we calculated out the work W done by the system, he change of its internal energy is the difference between Q and W.
W = pf*vf - pi*vi = R(Tf - Ti) = 8.314*74 = 615J
The change of its internal energy is:
Q - W = (1689-615)J = 1.07kJ (answer)