Question

The production capacity for acrylonitrile (C₃H₃N) in the United States is over 2 billion pounds per year. Acrylonitrile, the building block for polyacrylonitrile fibers and a variety of plastics, is produced from gaseous propylene, ammonia, and oxygen:

2C₃H₆(g) + 2NH₃(g) + 3O₂(g) → 2C₃H₃N(g) + 6H₂O(g)

Assuming 100% yield, determine the mass of acrylonitrile which can be produced from the mixture below:

Mass	Reactant
5.88×102 g	propylene
5.00 x 102 g	ammonia
1.00 x 103 g	oxygen

g = mass of acrylonitrile produced

What mass of water is formed from your mixture?

mass of water formed =  g

Calculate the mass (in grams) of each reactant after the reaction is complete:

Reactant	Mass remaining
propylene	g
ammonia	g
oxygen	g

Answer 1

Let us write the balanced equation

Balanced equation:
2 C₃H₆(g) + 2 NH₃(g) + 3 O₂(g) ====> 2 C₃H₃N(g) + 6 H₂O(g)

Mass of propylene = 5.88 x 10² g = 588 gm

Molar mass of propylene = 42.079 g/mol

Moles of propylene = 588 gm / 42.079 g/mol = 13.973 mol

Mass of ammonia = 5.00 x 10² g = 500 gm

Molar mass of ammonia = 17.03 g/mol

Moles of ammonia = 500 gm / 17.03 g/mol = 29.359 mol

Mass of oxygen = 1.0 x 10³ g = 1000 gm

Molar mass of oxygen = 32 g/mol

Moles of oxygen = 1000 gm / 32 g/mol = 31.25 mol

Among all reagent, propylene is the limiting reagent.

Hence moles of acetonitrile produced is equal to moles of propylene reacted

moles of acetonitrile produced = 13.973 Moles

Mass of  acetonitrile produced = 13.973 Moles x 53.06 g/mol = 741.46 gm

Moles of water produced = 41.920 Moles

Mass of water produced = 41.92 mol x 18 g/mol =  755.207 gm

Remaining reactants

Mass of propylene reacted = 588 gm (It is limiting reagent)

Hence no propylene will remain.

Moles of ammonia reacted is equal to moles of propylene reacted

Moles of ammonia reacted = 13.973 moles

Mass of ammonia reacted = 13.973 x 17.03 = 237.97 gm

Mass of ammonia left = 500 gm - 237.97 gm = 262.03 gm

Moles of oxygen reacted is equal to 1.5 times of propylene (in moles) reacted

Moles of oxygen reacted = 20.960 moles

Mass of oxygen reacted = 20.960 x 32 = 670.70 gm

Mass of oxygen left = 1000 gm - 670.70 gm =  329.3 gm

Reaction stoichiometry Limiting reagent Compound Coefficient Molar Mass Moles Weight C3H6(g) 2 42.07974 13.97347036 588 NH3(g) 17.03052 13.97347036 237.9754665 02(g) 31.9988 20.96020555 670.7014254 СЗНЗN(g) 53.06262 13.97347036 741.4689482 H2O(g) 18.01528 41.920411105 755.2079437 Units: molar mass - g/mol, weight - g.