Five moles of hydrogen gas are heated from `30^(@)C` to `60^(@)C` at constant pressure. Heat given to the gas is (given `R = 2 cal//mol` degrees)

Options

A. `750 cal`
B. `630 cal`
C. `1050 cal`
D. `1470 cal`

Answer

C

Explanation

c. `(Delta Q)_(P) = mu C_(P) Delta T = mu ((gamma)/(gamma - 1)) R Delta T`
`:. (Delta Q)_(P) = 5 xx (((7)/(5))/((7)/(5) - 1)) xx 2 xx 30`
`= 5 xx 2 xx (7)/(5) xx (5)/(2) xx 30 = 1050 cal`
(as `mu = 5` mol and `gamma = 7//5` for `H_(2))`