Calculate the density of a sample if the mass is 2.98g and the volume is 2.12l

Asolution contains 225 g of sodium chloride, nacl, dissolved in enough water to make a 0.25 l of solution. what is the molarity of the solution?

The name of the ion, s2-, is: sulfurous ion sulfide ion sulfur ion sulfate ion

Sodium sulfate dissolves as follows: na2so4(s) → 2na+(aq) + so42- (aq). how many moles of na2so4 are required to make 1.0 l of solution in which the na concentration is 0.10 m?