Question

Calculate the molality of 1 litre solution of 93 h2so4

Answer 1

m = n/msolvent 

So we need to find the number of moles of solute, and the mass of solvent that contains them: 

mass of solute in 100 mL of solution = 93g H2S04 

divide by the molar mass of H2SO4 to get the number of moles of solute: 

93 g H2SO4 / 98.08 = 0.948 moles of H2SO4. This is "n" in the original equation when referring to 100 mL of solution. 

Now we need to find the weight of the *solvent* (note this is not the weight of the solution). 

The weight of 100 mL of solution is 1.84 g/mL x 100 mL = 184 g of solution. 

This is made up of solute + solvent. So 93g solute + Ygrams solvent = 184g solution. 

Y = 184 - 93 = 91. So in 100 mL of solution there are 93g of solute, and 91g of solvent. 

Now you are ready to calculate the molality: 

Molality = n/msolvent = 0.948 / 91 = 0.01 mol/g = 10 mol/kg