Q16.21 P - Chemistry: Molecular Nature Of Matter And Change

Question

The formation of ammonia is one of the most important processes in the chemical industry: 

 

${\mathbf{N}}_{2\left(g\right)}\mathbf{+}\mathbf{3}{\mathbf{H}}_{\mathbf{2}\left(g\right)}\mathbf{\to }\mathbf{2}{\mathbf{NH}}_{3\left(g\right)}$

Express the rate in terms of changes in $\left[N_2\right]$, $\left[H_2\right]$, and $\left[{\mathrm{NH}}_3\right]$.

Step-by-Step Solution

Answer

The rate of reaction can be expressed as the disappearance of the reactant or the emergence of the product as 

$\begin{array}{rcl}\text{Reaction rate}& =& -\frac{∆\left[\text{N2}\right]}{∆\text{t}}\\ & =& -\frac{1}{3}\frac{∆\left[\text{H2}\right]}{∆\text{t}}\\ & =& \frac{1}{2}\frac{∆\left[\text{NH3}\right]}{∆\text{t}}\end{array}$

Why is industrial ammonia production so important?

Ammonia is used to cleanse water and as a component in the production of a wide range of goods, including plastics, explosives, textiles, insecticides, and colours.

Ammonia production is critical for the global agricultural business since it is used to make all nitrogen fertilisers.

The rate in terms of changes in [ N 2 ] , data-custom-editor="chemistry" [ H 2 ] , and data-custom-editor="chemistry" [ NH 3 ]

The rate of reaction can be represented in terms of reactant disappearance or product appearance as follows:

$\begin{array}{rcl}\text{Reaction rate}& =& -\frac{∆\left[\text{N2}\right]}{∆\text{t}}\\ & =& -\frac{1}{3}\frac{∆\left[\text{H2}\right]}{∆\text{t}}\\ & =& \frac{1}{2}\frac{∆\left[\text{NH3}\right]}{∆\text{t}}\end{array}$

The inverse of the fraction provides the molecules' stoichiometric coefficients