How many grams H2 are needed to react with 2.80 g of N2?

10.80g

Explanation:

N2 +3 H2 → 2 NH3

so we have 2180 g of N2

or 2.80 g ÷ 28.02 g/mol = 0.100 mol

1 mol of N2 react with 3 moles of H2

Therefore 0.100 mol of N2 react with 0.3 moles of H2

0.300 mol X Molar mass (2.00 g/mol) = 0.600 g