Question

If `10^(-4) dm^(3)` of water is introduced into a `1.0 dm^(3)` flask to `300K` how many moles of water are in the vapour phase when equilibrium is established ? (Given vapour pressure of `H_(2)O` at `300K` is `3170Pa R =8.314 JK^(-1) mol^(-1))` .
A. `1.27 xx 10^(-3) mol`
B. `5.56 xx 10^(-3)` mol
C. `1.53 xx 10^(-2)` mol
D. `4.46 xx 10^(-2)` mol

Answer 1

Correct Answer - A
`PV = nRT`
`3170 xx 10^(-3)= n xx 8.314 xx 300`
`n=(3170 xx 10^(-3))/(8.314 xx 300), V =1 Lt = 1dm^(2) = 10^(-3) m^(3)`
`n = 1.27 xx 10^(-3) mol`.