Question

Calculate the amount of solute needed to make each of the solution.
225g of a 10% (m/m) K2CO3 solution

.50kg of a 18% (m/m) KOH solution

please show work thanks

Answer 1

% m/m (w/w) = grams solute/100 g solution.
225g of 10% means you want 225 g of a 10g solute/100 g solution.

For 225g you will need how much solute?
10 x 225/100 = 22.5 g solute.

You can do it another way if that makes it any clearer.
% w/w is (grams solute/g solution)*100 = %
(g solute/225)*100 = 10
Solve for g solute. You should get the same answer either way.
(g solute) = 10*225/100 = 22.5 g solute.