Question

the reactants and products of photosynthesis are made of the same amounts of hydrogen, carbon, and oxygen atoms. when 6 molecules of carbon dioxide gas (co2) react with 6 molecules of water (h2o), the atoms in those molecules are rearranged to produce 1 molecule of glucose (c6h12o6) and 6 molecules of oxygen gas (o2). which chemical equation is balanced and represents the overall process of photosynthesis? co2 + h2o → c6h12o6 + 6o2 co2 + 6h2o → 6c6h12o6 + o2 6co2 + 6h2o → 6c6h12o6 + 6o2 6co2 + 6h2o → c6h12o6 + 6o2

Explanation:

Step1: Count carbon atoms

In the reactants, for every 6 molecules of $CO_2$, there are 6 carbon atoms. In the product glucose ($C_6H_{12}O_6$), there are 6 carbon atoms.

Step2: Count hydrogen atoms

In 6 molecules of $H_2O$, there are $6\times2 = 12$ hydrogen atoms. In 1 molecule of $C_6H_{12}O_6$, there are 12 hydrogen atoms.

Step3: Count oxygen atoms

In 6 molecules of $CO_2$, there are $6\times2=12$ oxygen atoms and in 6 molecules of $H_2O$, there are 6 oxygen atoms, so a total of $12 + 6=18$ oxygen atoms in reactants. In 1 molecule of $C_6H_{12}O_6$ there are 6 oxygen atoms and in 6 molecules of $O_2$ there are $6\times2 = 12$ oxygen atoms, a total of $6+12 = 18$ oxygen atoms in products.

Answer:

$6CO_2 + 6H_2O\longrightarrow C_6H_{12}O_6+6O_2$ (the fourth option)