What is an example of a stoichiometry practice problem?

Question

What is an example of a stoichiometry practice problem?

1 Answer

Impact of this question

17766 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2014-09-26T06:35:05

A stoichiometry problem would entail using a balanced chemical equation and mole and mass conversion factors in an attempt to
calculate the amounts of substances involved in a chemical reaction.

Let's take a basic example of a mass to mass stoichiometry problem.

Nitrogen gas and hydrogen gas are combined to form ammonia. What mass of ammonia can be produced from a 10.00 gram sample of nitrogen is combined with an excess of oxygen.

First we must write out a balanced chemical reaction for the process.

$N_{2} + 3 H_{2} \to 2 N H_{3}$ $N_2 + 3H_2 -> 2NH_3$

Next we must determine what is known and what we want to find.

10.00 grams $N_{2}$ $N_2$ $\to$ $->$ ? grams of $N H_{3}$ $NH_3$

Now we create a roadmap for the process.

grams $N_{2}$ $N_2$ $\to$ $->$ moles $N_{2}$ $N_2$ $\to$ $->$ moles $N H_{3}$ $NH_3$ $\to$ $->$ grams $N H_{3}$ $NH_3$

Then we find the molar mass of the substances.

$N_{2}$ $N_2$ = 2 x 14.01 = 28.02 g/mol $N_{2}$ $N_2$
$N H_{3}$ $NH_3$ = 1 x 14.01 + 3 x 1.01 = 17.04 g/mol $N H_{3}$ $NH_3$

We follow up with the conversion factors for each change of unit.

10.00 g $N_{2}$ $N_2$ x $\frac{1 m o l N_{2}}{28.02 g N_{2}}$ $(1 mol N_2)/( 28.02 g N_2)$ x $\frac{2 m o l N H_{3}}{1 m o l N_{2}}$ $(2 mol NH_3)/( 1 mol N_2)$ x $\frac{17.04 g N H_{3}}{1 m o l N H_{3}}$ $(17.04 g NH_3)/( 1 mol NH_3)$ =

Calculate the value and cancel the units.

= 12.16 g $N H_{3}$ $NH_3$

SMARTERTEACHER YouTube

Science

Math

Humanities

... and beyond

What is an example of a stoichiometry practice problem?

1 Answer

Related questions

Impact of this question