Answer :
Explanation
Given:
Mass of N2 = 42 g
Balanced chemical reaction: N2 + 3H2 → 2NH3
We know the molar mass of N2 = 28.0134 g/mol
the molar mass of NH3 = 17,031 g/mol
Required: Mass of NH3 that will be produced
Solution:
Step 1: Calculate the moles of N2
n = m/M where n is the moles, m is the mass and M is the molar mass
n = 42g/28.0134 g/mol
n = 1.499 mol
Step 2: Use the stoichiometry to calculate the moles of NH3
The molar ratio between N2 and NH3 is 1:2
Therefore the moles of NH3 = 1.499 mol x 2 = 2.998 mol
Step 3: Use the moles to calculate the mass of NH3
m = n x M
m = 2.998 mol x 17,031 g/mol
m = 51 g
Answer
B. 51 g