This is an oxidation-reduction (redox) reaction:

2 NV + 4 e- → 2 NIII (reduction)

2 O-II - 4 e- → 2 O0 (oxidation)

Ca(NO3)2 is an oxidizing agent, Ca(NO3)2 is a reducing agent.

### Word equation

calcium nitrate → calcium nitrite + oxygen

### Input interpretation

Ca(NO3)2 → Ca(NO2)2 + O2

calcium nitrate calcium nitrite oxygen

### Balanced equation

Balance the chemical equation algebraically:

Ca(NO3)2 → Ca(NO2)2 + O2

Add stoichiometric coefficients, c;, to the reactants and products:

c1Ca(NO3)2 → c2Ca(NO2)2 + c3O2

Set the number of atoms in the reactants equal to the number of atoms in the products for Ca, N and O:

Ca: c1 = c2

N: 2c1 = 2c2

O: 6c1= 4c2+2c3

Since the coefficients are relative quantities and underdetermined, choose a coefficient to set arbitrarily. To keep the coefficients small, the arbitrary value is ordinarily one. For instance, set c1 = 1 and solve the system of equations for the remaining coefficients:

c1 = 1 c2 = 1

c3=1

Substitute the coefficients into the chemical reaction to obtain the balanced equation: