Question

Question #9aec7

Answer 1

We will explore this stoichiometry problem of comparison of grams of A to grams of B using a sample problem.

How many grams of ammonia can be produced from 5.00 grams of hydrogen gas?

First we begin with a balanced chemical equation.

`N_2 + 3H_2 -> 2NH_3`

Next we determine what we have and what we want.
We have 5.00 grams of Hydrogen and we want grams of ammonia.

We set up a roadmap to solve the problem

`grams H_2 -> mol H_2 -> mol NH_3 -> grams NH_3`

We need the molar mass (`gfm`) of `H_2` and `NH_3`.
`H_2` = 2.02 g/mol and `NH_3` = 17.04 g/mol.

We need the mole ratio between `H_2` and `NH_3` 2:3 or 3:2

Now we set up conversion factors following the roadmap from above.
Unit we want in the numerator, unit to cancel in the denominator.

`5.00 g H_2 x (1 mol H_2)/(2.02 g H_2) x (2 mol NH_3)/(3 mol H_2) x(17.04 g NH_3)/(1 mol NH_3) =`

Multiply the numerators, and divide the denominators.

`28.2 g NH_3`

I hope this was helpful.
SMARTERTEACHER