The reaction is thus: 6H2O + 6CO2 –> C6H12O6 + 6O2

In non-chemical terms this says: six molecules of water plus six molecules of carbon dioxide react to produce one molecule of glucose and six molecules of oxygen.

There is a nice description of this reaction and more information about photosynthesis at Maricopa Community College here. They add, “The conversion of unusable sunlight energy into usable chemical energy, is associated with the actions of the green pigment chlorophyll. Most of the time, the photosynthetic process uses water and releases the oxygen that we absolutely must have to stay alive.”