Calculate the mass of MNO2 needed to produce 25.0 g of Cl2

I will solve this question assuming the reaction equation look like this:

MnO2 + 4 HCl - - - > MnCl2 + Cl2 + 2 H2O.

For every one molecule of MnO2 used, there will be one molecule of Cl2 formed. If the molecular mass of MnO2 is 87g/mol and molecular mass of Cl2 is 73.0 g/mol, the mass of MnO2 needed would be:

Cl mass/Cl molecular mass * MnO2 molecular mass=

25g / (73g/mol) * (87g/mol) * 1/1 = 29.8 grams