Sodium carbonate (Na2CO3) has a molar weight of 105.9885 g/mol. A solution contains 50. mM sodium ions and 25 mM carbonate ions. What is the concentration of sodium carbonate in the solutions as expressed as mass/volume percentage?

Answer 1

grams Na^+ = mols Na^+ x molar atomic mass Na^+.
Then % Na^+ = (g Na^+/100 mL) = ?

Carbonate is done similarly.