How do you balance the chemical equation: `~Ca(OH)_2 + ~(NH_4)_2SO_4 -gt ~CaSO_4 + ~NH_3 + ~H_2O` ?

`~Ca(OH)_2 + ~(NH_4)_2SO_4 -gt ~CaSO_4 + ~NH_3 + ~H_2O`

Step 1: Make a list of the number of each type of atom on the reactant and product sides of the equation.

`~Ca(OH)_2 + ~(NH_4)_2SO_4 -gt ~CaSO_4 + ~NH_3 + ~H_2O`

Reactants              Products

Ca: 1                      Ca: 1

O: 6                        O: 5

H: 10                      H: 5

N: 2                        N: 1

S: 1                        S: 1

Step 2: Pick an unbalanced atom to start with....

`~Ca(OH)_2 + ~(NH_4)_2SO_4 -gt ~CaSO_4 + ~NH_3 + ~H_2O`

Step 1: Make a list of the number of each type of atom on the reactant and product sides of the equation.

`~Ca(OH)_2 + ~(NH_4)_2SO_4 -gt ~CaSO_4 + ~NH_3 + ~H_2O`

Reactants              Products

Ca: 1                      Ca: 1

O: 6                        O: 5

H: 10                      H: 5

N: 2                        N: 1

S: 1                        S: 1

Step 2: Pick an unbalanced atom to start with. Add a coefficient to balance the unbalanced atom.

Let’s start with N. Ask yourself “What number can I multiply with the subscript of N on the product side of the equation that will give me the same number of N atoms as on the reactant side of the equation?” The answer would be 2.

So, place a coefficient of 2 in front of the compound on the product side of the equation that contains N. This changes the number of N atoms on the product side to 2 AND changes the number of H atoms to 8.

 `~Ca(OH)_2 + ~(NH_4)_2SO_4 -gt ~CaSO_4 + ~2NH_3 + ~H_2O`

Reactants              Products

Ca: 1                      Ca: 1

O: 6                        O: 5

H: 10                      H: 8

N: 2                        N: 2

S: 1                        S: 1

Step 3: Choose another unbalanced atom in the equation. Add a coefficient to balance the unbalanced atom.

Let’s balance H next. Notice that H is present in two compounds on the product side of the equation. Ask yourself “What number can I multiply with the subscript of H in one of the H-containing compounds on the product side that, when added to the other H-containing compound, will give me the same number of H atoms as on the reactant side of the equation?"

If we place a coefficient of 2 in front of the compound `~H_2O` , the total number of H atoms on the product side will equal the number of H atoms on the reactant side. Placing a coefficient of 2 in front of the compound `~H_2O` also changes the total number of O atoms on the product side to 6.

`~Ca(OH)_2 + ~(NH_4)_2SO_4 -gt ~CaSO_4 + ~2NH_3 + ~2H_2O`

Reactants              Products

Ca: 1                      Ca: 1

O: 6                        O: 6

H: 10                      H: 10

N: 2                        N: 2

S: 1                        S: 1

The reaction is now balanced.