Question

Calculate the molarity (M) of a 23% (w/v) copper sulfate solution (m.w. = 160.0 g/mol).

Answer 1

Answer: Molarity (M) of a 23% (w/v) copper sulfate solution:

Molarity = number of moles of solute / litres of solution

23% means 23g of Copper sulfate in 100mL of solution

Molecular weight of Copper sulfate is 160.0 g/mol

This means

160g = 1 mole of copper sulfate molecules

23g in 100mL solution = 23/160 moles = 0.144 moles of copper sulfate molecules in 100 mL solution

Molarity is no. of moles per L of solution.

So, converting the units, we get

Molarity = 0.144 moles/100mL = 1.44 moles/L (Answer)