What formula can be used to calculate [h30+]

Chemistry worksheet - i am not sure what they are asking for exactly?

Iron (fe) reacts with copper sulfate (cuso4) to form iron (ii) sulfate. in this reaction, cu2+ gains electrons to form cu. which statement is true about this reaction? fe(s) + cuso4(aq) → feso4(aq) + cu(s)

Magnesium is the limiting reactant in this experiment. calculate the theoretical yield of mgo for each trial. trial 1: trial 2: data mass of empty crucible with lid trial 1: 26.688 trial 2: 26.681 mass of mg metal, crucible, and lid trial 1: 26.994 trial: 2 26.985 mass of mgo, crucible, and lid trial 1: 27.188 trial 2: 27.180