The Balanced Chemical Equation for Photosynthesis

Photosynthesis is the process in plants and certain other organisms that uses the energy from the sun to convert carbon dioxide and water into glucose (a sugar) and oxygen.

Equation

Here is the balanced equation for the overall reaction:

6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂ 

Where:
CO₂ = carbon dioxide 
H₂O = water
light is required
C₆H₁₂O₆ = glucose
O₂ = oxygen

Explanation

In words, the equation may be stated as: Six carbon dioxide molecules and six water molecules react to produce one glucose molecule and six oxygen molecules.

The reaction requires energy in the form of light to overcome the activation energy needed for the reaction to proceed. Carbon dioxide and water don't spontaneously convert into glucose and oxygen.