Calculate the mass and the amount of salt formed if 0.2 mol of magnesium and 0.2 mol of formic acid are used for the reaction.

1. We write down the reaction equation:
2HCOOH + Mg → (HCOO) 2Mg + H2 ↑;
2.the lack of formic acid is taken, based on its data, we determine the amount of magnesium formate:
n ((HCOO) 2Mg) = n (2HCOOH): 2 = 0.2: 2 = 0.1 mol;
3.Calculate the mass of the formed salt:
m ((HCOO) 2Mg) = n ((HCOO) 2Mg) * M ((HCOO) 2Mg);
M ((HCOO) 2Mg) = 2 + 24 + 64 + 24 = 114 g / mol;
m ((HCOO) 2Mg) = 0.1 * 114 = 11.4 g.
Answer: 11.4 g, 0.1 mol.