How much energy would be required to heat two moles of methane by one degree if the gas is kept at constant volume?

1. 6.5 calories

2. 8.5 calories

3. 11 calories

4. 13 calories

 Moles of Methane = n = 2

Molar specific heat of methane at constant volume, Cv = 3R J/K/mol

Thus heat required to heat methane by 1 deg C is = nCv dT = 2*3R*1 = 6R J = 6 * 8.314 J =49.9 J

or heat =49.9/4.2 cal = 11.88 Cal

 use the formula q= ncdt.......now here process is carried out at constant volume so ...q=nc (v) dt

...that is 1 . 2 . 3R ....put the value of r u will get the answer......here n=2.......dt=1............and for a polyatomic gas c(v) is 3R!! .......R=8.314 J/mol K