How much heat energy in joules must be supplied to 14gms of nitrogen at room temperature to rise its temperature by `40^(@)C` at constant pressure? (Mol. Wt. of `N_(2)=28gm`, R=constant)

Options

A. 50 R
B. 60 R
C. 70 R
D. 80 R

Answer

C

Explanation

`Here, " " DeltaT=40^(@)C`
`C_(p)=(7)/(2)R` (for diatomic gases)
Number of moles, `mu=(14)/(28)=(1)/(2)`
Heat supplied at constant pressure , `Q=muC_(p)DeltaT`
`rArr " " Q=(1)/(2)xx(7)/(2)Rxx40=70R`