4.1 CYL - Chemistry (OpenStax)

Question

Write a balanced equation for the decomposition of ammonium nitrate to form molecular nitrogen, molecular oxygen and water. (Hint Balance oxygen last, since it is present in more than one molecule on the right side of the equation)

Step-by-Step Solution

Answer

The balanced equation will be \(2N{H_4}N{O_3} \to 2{N_2} + {O_2} + 4{H_2}O.\)

Writing unbalanced equation with unknown constants

\(wN{H_4}N{O_3} \to x{N_2} + y{O_2} + z{H_2}O,\) where w, x, y, and z, are unknown constants.

Determine the balanced equation

Count the number of times each element appears on either side of the reaction.

Reactants N= 2w, H= 4w, O= 3w.

Products N=2x, O= 2y+z, H= 2z.

2w = 2x………………………..(i)

4w = 2z………..……………….(ii)

3w = 2y+z…………...………….(iii)

Now, from equation (i):

w = x

From equation (ii):

2w = z

And putting value of “z” in (iii), we get:

3w = 2y + 2w

  w = 2y

Let y=1 then,

w = 2 x 1

    = 2.

x = 2

z = 2 x 2

  = 4.

Therefore, the balanced equation is \(2N{H_4}N{O_3} \to 2{N_2} + {O_2} + 4{H_2}O.\)