The molality of a solution containing $15.20 \ g$ of urea (molar mass = $60 \ g \ mol^{-1}$) dissolved in $150 \ g$ of water is:

Calculate the mass of urea $[NH_2CONH_2]$ required in making $2.5 \ kg$ of $0.25 \ m$ aqueous solution. (in $g$)

$A$ sample of drinking water is found to be severely contaminated with chloroform $(CHCl_3)$,which is a suspected carcinogen. The level of contamination is $15 \ ppm$ (by mass). Calculate the molarity of chloroform in the water sample.

Equal volumes of liquid $A$ $(d = 0.8 \ g/mL)$ and liquid $B$ $(d = 1.2 \ g/mL)$ are mixed to form a solution. Calculate the mole fraction of $A$ in the solution $(M_A = 16, M_B = 32)$.

If $100 \ g$ of a $0.2 \ m$ aqueous solution is diluted by adding $200 \ g$ of water,what will be the molality of the resulting solution?

Molality of $0.8 \ M \ H_2SO_4$ solution (density $1.06 \ g \ cm^{-3}$) is . . . . . . $\times 10^{-3} \ m$.