Four moles of a perfect gas heated to increases its temperature by `2^(@)C` absorbes heat of 40 cal at constant volume. If the same gas is heated at constant pressure the amount of heat supplied is, `(R=2" cal/mol K")`

Explanation

Number of moles `n = 4`
Change in temperature`Deltat=2`
Heat energy absorbed dQ = 40 cal.
Gas constant `R= 2 "cal/mole" K`
Heat energy absorbed at constant pressure
`dQ=dU+dW` per mole per kelvin.
But `dU=C_(v) dT` and dW=PdV
`C_(p)=C_(v)+R` Multiply with n.dT
`nC_(p)dT=nC_(v)dt+nRdT`
`nC_(p)dT`= Heat energy absorbed at constant pressure by n moles of gas.