Four students provide their teacher with an explanation of why photosynthesis is considered a chemical change. Luke: Photosynthesis is considered a chemical change because the CO2 molecules disappear and the O2 molecules reappear. Jackie: I know that photosynthesis is a chemical change because all of the reactants undergo a state of matter change and are all present as a product. Tara: Through photosynthesis, the CO2 and water are changed into new substance, glucose, therefore it is considered a chemical change. Skyler: Photosynthesis is a chemical change because solar energy is required. Which student provides the best explanation of why photosynthesis is a chemical change

The best explanation was provided by the student Tara who said: "Through photosynthesis, the CO2 and water are changed into new substance, glucose, therefore it is considered a chemical change".

Explanation:

A chemical change is one which is not easily reversible and which results in the formation of new subsatances.

For example, in photosynthesis,a new substance, glucose is formed from the original substansubstances, carbon dioxide and water. Also, the reverse process of the formation of carbon dioxide and water from glucose is not easily obtained in plants.

From explanations provided by the students :

Luke does not give any explanation of the process but only an observation

Jackie's explanation does not state the main reason why a chemical change differs from a physical one.

Tara, gives the best explanation as the reason why a change that occcured is a chemical change is clearly stated.

Skyler does not state the main reason why photosynthesismis a chemical change as well, because even physical changes like evaporation of water involves solar energy.