A gas is confined to a cylinder under constant atmospheric pressure, as illustrated in the following figure. When 0.490kJ kJ of heat is added to the gas, it expands and does 213J J of work on the surroundings.
a) What is the value of ΔH for this process?
ANSWER: 0.49 kJ
B) What is the value of ΔE for this process? (Express your answer using two decimal places)
ANSWER: I subtract 0.49 – 213 = 212.51 kJ but It’s says that is wrong!! Can someone help me please??
Thank you
2 Answers

B) It is because of the difference in units; one is kJ, the other in J. Noting that kJ=1000J
ΔE = 0.49kJ – 213J
= 0.49*1000  213 = 490  213 = 277
Answer: 277 Joule

How did you find the ΔH?