Posted by Mary on .
Three moles of an ideal monatomic gas are at a temperature of 345 K. Then, 2531 J of heat are added to the gas, and 1101 J of work are done on it. What is the final temperature of the gas?
delta U= 3/2nR(T final T initial)
(2531J  1101J) = 3/2(3.0mol)(8.31)(T final  345K)
1430J = 37.395(T final  345K)
1430J/ 37.395 = T final  345K
38.24 + 345K = T final
383.2404K = T final
This answer is incorrect. Please explain to me where I went wrong.

Physics 
Cale,
Delta U would be 2531J + 1101J instead of 2531J  1101J, because the system is doing work instead of having work done to it.
(2531J + 1101J)= 3632J
3632J = 3/2(3.0mol)(8.31)(T final  345K)
3632J = 37.395(T final  345K)
3632J/ 37.395 = T final  345K
97.12 + 345K = T final
442.125K = T final