Differentiate among a chemical formula, a molecular formula, and a
formula unit.

We need 116.1 kg of Li2O

Explanation:

Step 1: Data given

MAss of water = 70 kg = 70000 grams

Molar mass H2O = 18.02 g/mol

Molar mass of Li2O = 29.88 g/mol

Step 2: the balanced equation

Li2O(s)+H2O(g)→2LiOH(s)

Step 3: Calculate moles H2O

Moles H2O = mass H2O / molar mass H2O

Moles H2O = 70000 grams / 18.02 g/mol

Moles H2O = 3884.6 moles

Step 4: Calculate moles Li2O

For 1 mol Li2O we need 1 mol H2O to produce 2 moles LiOH

For 3884.6 moles H2O we need 3884.6 moles Li2O

Step 5: Calculate mass Li2O

MAss Li2O = moles * molar mass

MAss Li2O = 3884.6 moles *29.88g/mol

Mass Li2O = 116071.8 grams = 116.1 kg

We need 116.1 kg of Li2O