Chemistry Weight Volume question

N2 + 3H2 ---> 2NH3
If 4 g of H2 are available along with unlimited N2, how much NH3 (in liters) can be produced?

We studied this a long time ago in my class and i forgot how to do it :(

This is a three-step stoichiometry problem.

In this case the "x" is representing a multiplication sign and the "/" divide sign.
You have 4 g of H2 = 4 grams of Hydrogen.

You need to find how many liters of NH3 you can produce.

You have to first go from grams of hydrogen (H2) to moles of hydrogen.

4 g H2 x 1 mole/ molar mass of H2 (which is 2 g H2) = 4 x 1 = 4/2 = 2. Grams cancel out. You have 2 moles of H2.

Now go from moles of H2 to moles of NH3 (what you are trying to find in liters).

2 mol H2 x (# moles of NH3 = 2) / (# moles of H2 = 3)--refer to original equation..the coefficient in front of the compound.

2 x 2 = 4/3 = 1.33 ----> You have 1.33 moles of NH3.

Last step..convert moles of NH3 to liters of NH3.

1.33 mol NH3 x 22.4 L NH3/1 mol = 1.33 x 22.4 = 29.792

Round.

29.80 L NH3

29.80 liters of NH3 can be produced.

Hope this helps!