Calculate the amount of the substance and the mass of the formed lithium oxide Li2O

Calculate the amount of the substance and the mass of the formed lithium oxide Li2O, if 2 mol of lithium entered into a reaction with oxygen.

Decision:
1. Let us write the equation for the reaction of lithium with oxygen with spaced coefficients:
4Li + O2 = 2Li2O;
2. The coefficient of lithium oxide is 2 times less than that of lithium. This means that the amount of substance in the oxide will be 2 times less, that is, 1 mol.
3. Find the molecular weight of lithium oxide:
2 * 7 + 16 = 30 g / mol;
4. The mass of lithium oxide is:
30 * 1 = 30 grams.
Answer: the amount of substance in lithium oxide is 1 mol, the mass of lithium oxide is 30 grams.