Video Transcript
Which of the following is the correct chemical equation for photosynthesis? (A) C6H12O6 aqueous plus six O2 gas reacts in the presence of light to form six CO2
gas plus six H2O liquid. (B) C6H12O6 aqueous plus six CO2 gas reacts in the presence of light to form six O2
gas plus six H2O liquid. (C) Six H2O liquid plus six O2 gas reacts in the presence of light to form C6H12O6
aqueous plus six CO2 gas. (D) Six CO2 gas plus six H2O liquid reacts in the presence of light to form C6H12O6
aqueous plus six O2 gas. (E) Six CO2 gas plus six H2O liquid reacts while heating to form C6H12O6 aqueous plus
six O2 gas.
Photosynthesis is an example of a photochemical reaction that occurs inside
plants. A photochemical reaction is a type of chemical reaction that is initiated by the
absorption of energy from light. We can see that each reaction has either light or heat above the reaction arrow. This indicates that light or heat is required for the reaction to occur. Since a photochemical reaction is initiated by light and not heat, we can eliminate
answer choice (E).
Now let’s talk about the process of photosynthesis in some more detail. Photosynthesis occurs inside the leaves of a plant inside a structure called
chloroplasts. Chloroplasts contain a molecule called chlorophyll, which can absorb light from the
Sun. The light initiates a reaction between carbon dioxide, which is absorbed from the
atmosphere, and water that enters the plant through its roots. This reaction produces glucose, a simple sugar the plant uses as energy to grow. The other product of this reaction is oxygen gas, which leaves the plant and enters
the atmosphere.
Looking through our answer choices, we can see that answer choice (D) is the only one
that has carbon dioxide and water as a reactant and glucose and oxygen as a
product. So it the correct answer. So the correct chemical equation for photosynthesis is answer choice (D). Six CO2 gas plus six H2O liquid reacts in the presence of light to form C6H12O6
aqueous plus six O2 gas.
