Answer: 29.2
Explanation:
From the coefficients of the equation, we know that for every 3 moles of hydrogen consumed, 1 mole of nitrogen is consumed.
This means we would need 6.25/3 = 2.0833333333333 mol of nitrogen.
Nitrogen has an atomic mass of 14.007 g/mol, so 2.0833333333333 moles of nitrogen have a mass of (14.007)(2.0833333333333) = 29.2 g (to 3 sf)