Question

calculate the molarity of each of the following solutions

1.30 g of Ca(NO3)2.6H2O in 4.3 litre of solution

2.30 ml of 0.3 M H2SO4 diluted to 500 ml

Answer 1

1.Assuming the compound given in your question is Co(NO3)2.6H2O which has molar mass equal to 291 g.

Number of moles in 30 g of Co(NO3)2.6H2O = 30/291 = 0.103

Volume of solution = 4.3 L

Molarity =

number of moles of solute/ volume of solution in liter = 0.103/4.3 =0.024 M.

2.

Number of moles of 0.3 M H₂SO₄solution in 30 ml of solution = (0.3/1000) X 30 =0.009

Volume of diluted solution = 500 ml = 0.5 L

Molarity = 0.009/0.5 = 0.018 M