Question

The density of a solution prepared by dissolving 120g urea

Answer 1

Explanation:

the density of a solution prepared by dissolving 120g of urea in 1000g of water is 1.15g/ml .

Answer 2

Explanation:

We know that

Density of solution = Mass of solution / Volume of solution

therefore , volume of solution = Mass / density = 120+1000 g/ 1.15 g ml-1 = 1120 *100 / 115 = 973.91 ml = 974 * 10 -3 litres

Now ,

n (no. of moles of solute) = 120 g / 60.05 g = 2 mol [since, molecular mass of urea is 60.05 g]

Now ,M(Molarity) = n (no. of moles of solute)/ Volume of solution in litres

Molarity = 2 / 974 * 10 ^ (-3)

Molarity = 2000/974 = 2.05 M