Question

Ammonia is produced by the reaction of nitrogen gas with hydrogen gas. The balanced reaction is: N2 + 3H2 --> 2NH3. If you start with 19.64 g of H2, how many grams of NH3 can be produced?

Answer 1

Convert the mass of reactant given to moles and use the stoichiometric coefficients to find moles product made. Set up a ratio using the species of interest, like so:

e.g. for a general reaction:

\(\color{red}{a}A + \color{blue}{b}B\) \(\rightleftharpoons\) \( \color{green}{c}C\)

where upper case are the species (A,B,C), and lower case (a,b,c) are the coefficients ,

\(\dfrac{n_A}{\color{red}{a}}=\dfrac{n_B}{\color{blue}{b}}=\dfrac{n_C}{\color{green}{c}}\)

From here you can isolate what you need.
For example: if you have 2 moles of B, how many moles of C can you produce?

solve algebraically: \(\dfrac{2}{\color{blue}{b}}=\dfrac{n_C}{\color{green}{c}}\rightarrow n_C=\dfrac{2*\color{green}{c}}{\color{blue}{b}}\)
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To convert mass to moles, use the relationship:

\(n=\dfrac{m}{M}\)

where, M=molar mass, m=mass, and n= moles.

Answer 2

How do I convert the reactants mass to moles and then use the equation for general reaction you provided.

Answer 3

use the equation at the very bottom, it works to convert mass to moles or moles to mass.