How many moles of ammonia (NH3) would be produced if 2.5 moles of nitrogen (N2) reacted with excess hydrogen (H2).

Question

This is the balanced chemical equation for the reaction that produces ammonia (NH₃) from nitrogen (N₂) and hydrogen (H₂).

N₂ (g)+3 H₂ (g) → 2 NH₃ (g)

A. Using the mole ratio from the chemical equation, calculate how many moles of ammonia (NH₃) would be produced if 2.5 moles of nitrogen (N₂) reacted with excess hydrogen (H₂).

Answer 1

Since there is excess hydrogen, that means that the concentration of hydrogen is not limiting. The equation is balanced so we also don't have to worry about balancing.

When we have a balanced chemical equation/reaction, we basically have a conversion tool. Using the proportions of the amount of the molecules, we can convert from any reagent or product to any other reagent or product. In the context of this reaction, for every mole of N2 and every 3 moles of H2 we obtain 2 moles of NH3. Since we have the amount of N2 and excess of hydrogen, we only need to work with the amount of N2. As we said before, for every mole of N2 we get 2 moles of NH3 and using this proportions we can make a conversion tool and calculate how many moles of NH3 we obtain from 2.5 moles of N2.

2.5 moles of N2 * (2 moles of NH3/ 1 mole of N2) = moles of NH3

We place the N2 on the bottom of the fraction in order to cancel out the units and obtain moles of NH3.

2.5 moles of N2 * (2 moles of NH3/ 1 mole of N2) = 5 moles of NH3

We end up with 5 moles of NH3.

Answer 2

Use the coefficients in the balanced chemical equation. create an unit factor with the 2 substances in question.

2.5 mols N2 ( 2 mols NH3 / 1 mol N2 ) = 5 mols of NH3 produced from 2.5 mols of N2

Yours in Chemistry Success!

Dale Swanson