Question

this image shows the process of photosynthesis. the law of conservation of mass reminds us that matter is neither created nor destroyed, so the atoms present in the reactants of photosynthesis are still present in the products of photosynthesis. which of these equations accurately portrays this fact?
a) \\( \text{co}_2 + \text{h}_2\text{o} + \text{light energy} \
ightarrow \text{c}_6\text{h}_{12}\text{o}_6 + \text{o}_2 \\)
b) \\( 6\\ \text{co}_2 + 6\\ \text{h}_2\text{o} + \text{light energy} \
ightarrow \text{c}_6\text{h}_{12}\text{o}_6 + 6\\ \text{o}_2 \\)
c) \\( 6\\ \text{o}_2 + 6\\ \text{h}_2\text{o} + \text{light energy} \
ightarrow \text{c}_6\text{h}_{12}\text{o}_6 + 6\\ \text{co}_2 \\)
d) \\( 6\\ \text{co}_2 + 6\\ \text{h}_2\text{o} + \text{light energy} \
ightarrow 6\\ \text{c}_6\text{h}_{12}\text{o}_6 + 6\\ \text{o}_2 \\)

Explanation:

1. The process of photosynthesis uses carbon dioxide (\(CO_2\)) and water (\(H_2O\)) in the presence of light energy to produce glucose (\(C_6H_{12}O_6\)) and oxygen (\(O_2\)).
2. According to the Law of Conservation of Mass, the number of atoms of each element must be equal on both sides of the chemical equation.

• For option B:
• On the reactant side:
• Carbon (C): \(6\times1 = 6\) (from \(6\ CO_2\)).
• Hydrogen (H): \(6\times2=12\) (from \(6\ H_2O\)).
• Oxygen (O): \(6\times2 + 6\times1=12 + 6 = 18\) (from \(6\ CO_2\) and \(6\ H_2O\)).
• On the product side:
• Carbon (C): \(6\) (from \(C_6H_{12}O_6\)).
• Hydrogen (H): \(12\) (from \(C_6H_{12}O_6\)).
• Oxygen (O): \(6 + 6\times2=6 + 12 = 18\) (from \(C_6H_{12}O_6\) and \(6\ O_2\)).
• Option A has an incorrect number of atoms (e.g., H and O are not balanced). Option C has incorrect reactants (uses \(O_2\) instead of \(CO_2\) as a main reactant for photosynthesis). Option D has an incorrect product (produces \(6\ C_6H_{12}O_6\) which is not the correct stoichiometry for photosynthesis).

Answer:

B. \( 6\ CO_2 + 6\ H_2O + \text{light energy}
ightarrow C_6H_{12}O_6 + 6\ O_2 \)