Question

The molality of a urea solution in which ` 0.0100 g ` of urea, ` [(NH_(2))_(2)CO] ` is added to ` 0.3000 dm^(3) `of water at STP is
A. 0.555 m
B. `5.55 xx 10^(-4)m`
C. 33.3
D. `3.33 xx 10^(-2)m`

Answer 1

Correct Answer - B
Molar mass of urea, `(NH_(2))_(2)CO=32 + 12 + 16 = 60 g "mol"^(-1)`
`"Molality"=((0.01//60)"mole")/(0.300dm^(3))`
`= 5.55 xx 10^(-4) "mol dm"^(-3)`
`= 5.55 xx 10^(-4) m.`