1. Which compound contains the highest percentage of magnesium by mass?
6. Which of the following is a weak electrolyte in aqueous solution?
4. What is the molarity of sodium ions in a solution prepared by diluting 250. mL of 0.550 M Na2SO4 to 1.25 L?
(A) 0.110 M
(B) 0.138 M
(C) 0.220 M
(D) 0.275 M