The reaction for the decomposition of ammonia can be written as shown below. If a student starts with 21.7 g of ammonia how many grams of hydrogen gas will be produced by the reactions? Why

2NH3 = N2 + 3H2

A. 1.28g

B. 2.55g

C. 3.85g

D. 32.5g

Option C. 3.85g

Explanation:

2NH3 N2 + 3H2

Molar Mass of NH3 = 14.0067 + (3x1.0078) = 14.0067 + 3.02352 = 17.03022g/mol

Mass of NH3 from the balanced equation = 2 x 17.03022 = 34.06044g

Molar Mass of H2 = 2x1.00784 = 2.01568g/mol

Mass of H2 from the balanced equation = 3 x 2.01568 = 6.04704g

From the equation,

34.06044g of NH3 produced 6.04704g of H2

Therefore, 21.7 of NH3 will produce = (21.7 x 6.04704) / 34.06044 = 3.85g of H2