1 `cm^(3)` of waterr at its boiling point absorbs 540 calories of heat to become steam with a volume of 1671 `cm^(3)`. If the atmospheric pressure ` = 1.013 xx 10^(5) N//m^(2)` and the mechanical equivalent of heat ` = 4.19` J/calorie, the energy spent in this process in overcoming inter molecular forces is

Options

A. `540 cal`
B. `40 cal`
C. `500 cal`
D. Zero

Answer

C

Explanation

c. Energy spent in overcoming inter-molecular forecs.
`Delta U = Delta Q - Delta W`
`Delta Q - P(V_(2) - V_(1))`
`= 540 - (1.013 xx 10^(5) (1671 - 1) xx 10^(-6))/(4.2)`
`implies 500 cal`