Limiting Reagents

A Limiting Reagent is the reagent that limits the amount of products that can be formed.

For example, nitrogen gas is prepared by passing ammonia gas over solid copper(II) oxide at high temperatures. The other products are solid copper and water vapor.

2 NH₃(g) + 3 CuO(s) → N₂(g) + 3 Cu(s) + 3 H₂O(g)

If 18.1 g of NH₃ are reacted with 90.4 g of CuO, which is the limiting reagent? How many grams of N₂ will be formed?

First we compute the number of moles of NH₃ (M.W. = 17.031 g/mole) and the number of moles of CuO (M.W. = 79.5 g/mole).

To determine which reagent is limiting we use the mole ratio from the chemical equation to convert moles NH₃ to moles CuO.

So, only 1.14 moles of CuO is available, therefore CuO is the limiting reagent. That is, CuO will run out before the NH₃ does.

The mass of N₂ produced will be

Limiting Reagents:

Homework from Chemisty, The Central Science, 10th Ed.

3.1, 3.7, 3.9, 3.11, 3.55, 3.57, 3.59, 3.61, 3.63, 3.65, 3.67, 3.69, 3.71, 3.73, 3.75, 3.77, 3.79

If you find these tutorials helpful, please consider making a

donation

to support our research and teaching efforts

These tutorials are sponsored by PhySy, the maker of PhySyCalc on iPhone, iPad, or Mac OS, and RMN on Mac OS.
PhySyCalc is the only calculator app that let's you use units directly in calculations.
RMN is an intuitive multi-dimensional signal processing app on MacOS.

Feel free to contact us if you have questions about the material on this page.

You are here

Search form

Homework from Chemisty, The Central Science, 10th Ed.