chemistry help?

Question

1)If 14.40 grams of RbCl are dissolved in water to make a solution of 0.224 L, the density is found to be 1.047 g/cm3. Calculate the molality of the solute.
2)10 mg of a certain protein was dissolved in water to make a solution of 4.00 mL at 22C. If the osmotic pressure is 1.35 torr, what is the molecular mass of the protein?

Answer 1

the molar mass of Rb CL is 35.5+85.5 = 121g

the mass of the solution is 224*1.047 =234.5g so inwater
234.5-14.4 = 220.2g of water

molality= nomber of mole/kgwater

m = 14.4/(121*0.2202) =0.54 mole/kg

2) the mass in one liter is 0.01/0.004=2.5g/L

OP = RTc/M

M= RTc/OP= 8.31*295*2.5/1.35*136 =33.8kg=33800