How many molecules(not moles) of NH3 are produced from 8.69x10 ^-4g of H2? Express your answer numerically as the number of molecules.

Question

How many molecules(not moles) of NH3 are produced from 8.69x10 ^-4g of H2?

Express your answer numerically as the number of molecules.

Answer 1

First, let's look at the balanced equation for the synthesis of NH₃ from H₂ and N₂:

3H₂(g) + N₂(g) ==> 2NH₃(g)

We are given 8.69x10^-4 g of H₂, and we must first convert this to moles of H₂. Then from that, we use the stoichiometry of the balanced equation to find moles of NH₃ and finally, we use Avogadro's number to convert moles of NH₃ to molecules of NH₃. All of this assumes that N₂ is not limiting.

moles H₂ present = 8.69x10^-4 g H₂ x 1 mol H₂/2.02 g = 4.30x10^-4 moles H2

moles NH₃ formed = 4.30x10^-4 moles H₂ x 2 moles NH₃/3 moles H₂ = 2.87x10^-4 moles NH₃

molecules NH₃ = 2.87x10^-4 moles x 6.02x10²³ molecules/mole = 1.73x10²⁰ molecules of NH₃