When 1 mol of gas is heated at constant volume temperature is raised from 298 to 308 K. Heat supplied to the gas is 500 J. Then which statement is correct ?
- q = w = 500 J, E = 0
- q = E = 500 J, w = 0
- q = -w = 500 J, E = 0
- E = 0, q = w = -500 J
Answer
(2) q = E = 500 J, w = 0
Solution
At constant volume, V = 0 ⇒ w = -pext V = 0
First law: E = q + w
⇒ E = q + 0 = q
∴ q = E = 500 J, w = 0
Answer: (2)