Answer:
21.2 g
Explanation:
From the coefficients of the equation, we know that for every mole of nitrogen produced, 3 moles of CuO are consumed.
CuO has a formula mass of 79.545 g/mol, so 181 g is equal to 181/79.545 = 2.275 mol.
This means we need 2.275/3 = 0.758 mol of nitrogen.
Nitrogen has an atomic mass of 28.014 g/mol, so the answer is (28.014)(0.758) = 21.2 g to 3 sf
