In Joly's differential steam calorimeter, `3g` of an ideal gas is ccontained in a rigid closed sphere at `20^@C`. The sphere is heated by steam at `100^@C` and it is found that an extra `0.095 g` of steam has condensed into water as the temperature of the gas becomes constant. Calculate the specific heat capacity of the gas in `(Jg^(-1) K^(-1).` The latent heat of vaporization of `water = 540 cal g ^(-1)`.

Explanation

In Jolly's differential steam calorimeter,
`Cv=(m_2L)/(m_1(theta_2-theta_1))`
`m_2` = Mass of steam condensed
`=0.095g`
`L=540 cal//g = 540 xx 4.2 J//g.`
`m_1` = Mass of gas present `=3 g`
`theta_1=20^@C`, `theta_2= 100^@C`.
implies `Cv =(0.095 xx 540 xx 42)/(3 xx (100-20))`
`=0.89 =0.9 J//gK`.