Question

Calculate the molality of potassium carbonate solution formed by dissolving 2.5 gram of it in 1 litre of solution density of solution is equal to 0.85 gram per litre

Answer 1

Answer:

Explanation:

Molality or Molal concentration is a measure of the concentration of a solute in a solution given as a ratio of the amount of substance (in moles) in a specified amount of mass of the solvent. 

Formula for Molality is a s follows:

molality = moles of solute / mass of solvent (kg)

Find moles of Potassium carbonate 

molar mass = 138, mass = 2.5

moles  = mass / molar mass 

          = 2.5 / 138

          =  0.01812   

Find mass of the solvent

0.85 g/ml is 0.85kg/liter (conversion factor is 1000)

Therefore 1 liter will have 850g of the solution or 0.85kg

The molality will be:

m = moles of solute/ mass of solvent

          0.01812/ 0.85

       = 0.02132 mol/kg

Answer 2

Explanation:

the molality of potassium carbonate solution formed by dissolving 2.5 gram of it in 1 litre of solution density of solution is equal to 0.85 gram per litre