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

Number of molecules in 14 grams of nitrogen
`n=("mass of nitrogen")/("molecules wt")=(14)/(28)=1/2`
Since nitrogen is diatomic
`therefore C_(p)=(7)/(2)R`
Therefore the amount of heat energy supplied
`=nxxC_(p)xxdT`