Question

Photosynthesis produces glucose, c6h12o6, and oxygen from carbon dioxide and water: 6CO2​+6H2​O→C6​H12​O6​+6O2​ ag how would you determine the δrh° value for this reaction experimentally?

(a) Measure the temperature change during the reaction and calculate ΔrH∘Δr​H∘ using the formula ΔrH∘=q/molΔr​H∘=q/mol.
(b) Perform a titration to determine the concentration of each reactant and product, then use the concentrations in the enthalpy change formula.
(c) Use a calorimeter to measure the heat evolved or absorbed during the reaction and calculate ΔrH∘Δr​H∘ based on the calorimeter readings.
(d) Apply Hess's law by combining known reactions to derive the enthalpy change for the given photosynthesis reaction.

Answer 1

The enthalpy change (ΔrH°) for the photosynthesis reaction can be determined experimentally by using a calorimeter, the most suitable option, to measure the heat exchanged during the reaction.

Step-by-step explanation:

To determine the ΔrH° value for the photosynthesis reaction 6CO2 + 6H2O → C6H12O6 + 6O2 experimentally, option (c) using a calorimeter to measure the heat evolved or absorbed during the reaction is the most appropriate method. By placing the reaction mixture in a calorimeter and measuring the temperature change, you can calculate the enthalpy change ΔrH° for the photosynthesis reaction based on the calorimeter readings and the known heat capacities of the substances involved. This method directly measures the heat exchanged during the reaction and, therefore, is suitable for calculating the reaction enthalpy.

Options (a) and (b) are less suitable. Option (a) involves measuring temperature change without the controlled environment of a calorimeter and may lead to inaccurate results. Option (b), titration, is typically used for reactions in solution and for determining concentrations, not for measuring heat change or enthalpy directly. Option (d), applying Hess's law, is theoretically possible but may not be practical for photosynthesis because it requires finding a series of known reactions that when combined will equal the photosynthesis reaction, and those reactions might not be readily available or may introduce additional complexities.