Question

How do you balance `NH_3 + H_2SO_4 -> (NH_4)_2SO_4`?

Answer 1

`color(red)(2)NH_3+H_2SO_4->(NH_4)_2SO_4`

Explanation:

The balanced equation is the following:

`color(red)(2)NH_3+H_2SO_4->(NH_4)_2SO_4`

Explanation:
First start by looking at the sulfate group `SO_4`, you will need to leave this group intact.

Second, we have two nitrogen atoms in the product side, and only one in the reactants side, therefore, we can multiply `NH_3` by `color(red)(2)`.

Third, look at the hydrogen atoms, you will find `color(blue)(8)` in each side of the reaction, and therefore, your reaction is balanced.

In some cases, I prefer to balance equations using groups (or polyatomic ions) rather than atoms.

Answer 2

`2NH_3 + H_2SO_4 → (NH_4)_2SO_4`

Explanation:

You need to make sure that all the elements are equal on both sides.

The first step is write down what you have

`NH_3 + H_2SO_4 → (NH_4)_2SO_4`

N: 1 the side in front of the arrow, 2 on the side after the arrow
H: 5 on the side before the arrow, 8 on the side after the arrow
`SO_4`: 1 on each side

Now you can see that you need to change the amount of N and H on the side in front of the arrow, to match the amount of N and H after the arrow.

Step two add a number in front of the elements to make both side match:

`2NH_3 + H_2SO_4 → (NH_4)_2SO_4`

Step three, check again, make changes if necessary:
N: 2 on both sides
H: 8 on both sides
`SO_4`: 1 on each side

As you can see, the reaction is now balanced :)