A chemist makes a solution of K2SO4 by dissolving 21.7 g K2SO4 in water to make 100.0 mL of solution. What is the concentration of SO42− ions in the solution? Assume that K2SO4 is the only solute in the solution. The molar mass of K2SO4 is 174.27 g/mol.

Answer 1

mols K2SO4 = grams/molar mass = ?
mols [SO4]^2- = mols K2SO4 since there is 1 mols SO4 in 1 mol K2SO4.
L = 100 mL = 0.100 L
Then M = mols/L