An open flask contains air at `27^(@)C` Calculate the temperature at which it should be heated so that
(a) `(1)/(3)` rd of air measured at `27^(@)C` escapes out

Answer

`177^(@)C`

Explanation

Let the initial number of moles of `27^(@)C (300 K)` be `n`
No. of moles of air left when heated to `TK = n - n/3 = (2n)/(3)`
At constant pressure `n_(1)T_(1) = n_(2)T_(2)` or `n xx 300 = (2n)/(3) xx T` or `T = (300 xx 3)/(2) = 450 K = 177^(@)C`