Chemistry in uni

Question

Hey!

I have: 15g of NH₃ in NH₃ --> N₂ + H₂

How much H₂ (in grams) can i maximum make?

Thanks for helping me out :)

Answer 1

Hello!

Firstly, you will need to balance the original equation to the following:

2(NH3) = (2)N2 + (3)H2

I would find the total number of grams that NH3 contains before making our ratio table:

(NH3) = 14 + 1(3) = 17g/ mol

Since you were given only 15g of NH3, we will need to set up our fraction which will be (15g NH3 / 17g/ mol NH3) which will equal 0.882 mol of NH3 (considering the use of 3 sig figs)

Next, lets find out the total number of grams of H2 = 1.008(2) = 2.016g/ mol H2

To find the maximum amount of H2 that can be produced we will need to multiply our mole ratio (0.882 mol NH3) by the fraction (3 mol H2 / 2 mol NH3) to remain with 1.32 mol of H2.

With 1.32 mol of H2, we can easily find the total number of grams by multiplying (1.32 mol H2) x (2.016g / mol H2) to give us a final answer of 2.67 g of H2 being produced.