Question

How many grams of H2 are required to produce 18.5 g of NH3

Answer 1

Explanation:

We are given: mass of NH3 = 18.5 g

We know: molar mass of NH3 = 17.031 g/mol

: molar mass of H2 = 2.016 g/mol

We first determine the number of moles of NH3:

$\begin{gathered} n\text{ = }\frac{m}{M} \\ \\ \text{ = }\frac{18.5}{17.031} \\ \\ \text{ = 1.086 mol} \end{gathered}$

We then determine the number of moles of H2 from the number of moles of NH3:

$\begin{gathered} n(H2)\text{ = }\frac{3}{2}\times n(NH3) \\ \\ \text{ = }\frac{3}{2}\times1.086 \\ \\ \text{ = 1.629 mol} \end{gathered}$

We then determine mass of H2 required:

$\begin{gathered} n\text{ = }\frac{m}{M} \\ \\ \therefore\text{ m = nM } \\ \\ \text{ = 1.629}\times2.016 \\ \\ \text{ = 3.28 g} \end{gathered}$

Answer:

grams of H2 required = 3.28 g