Question

Given $6{{\text{H}}_{\text{2}}}{\text{O}} + {\text{6C}}{{\text{O}}_2} \to {{\text{C}}_{\text{6}}}{{\text{H}}_{{\text{12}}}}{{\text{O}}_{\text{6}}} + 6{{\text{O}}_{\text{2}}}$
How many grams of glucose are made if you start with 88.0 g of ${\text{C}}{{\text{O}}_{\text{2}}}$?

Answer 1

Here, first we have to calculate the moles of carbon dioxide produced. Then, we have to identify the moles of carbon dioxide needed to produce one mole of glucose $\left( {{{\text{C}}_{\text{6}}}{{\text{H}}_{{\text{12}}}}{{\text{O}}_{\text{6}}}} \right)$. After that, we calculate the moles of glucose produced. And at last we have to calculate the mass of glucose produced by the formula, Number of moles=$\dfrac{{{\text{Mass}}}}{{{\text{Molar}}\,{\text{mass}}}}$

Complete step by step answer:
Now, we have to calculate the moles of carbon dioxide produced. The given mass of carbon dioxide is 88.0 g. The molar mass of carbon dioxide is 44 g/mol.
Moles of carbon dioxide=$\dfrac{{{\text{Mass}}}} {{{\text{Molar}}\,{\text{mass}}}}$
$\Rightarrow$ Moles of carbon dioxide=$\dfrac{{88\,{\text{g}}}} {{44\,{\text{g}}\,{\text{mo}}{{\text{l}}^{ - 1}}}} = 2\,{\text{mol}}$
So, 2 moles of carbon dioxide is used in the reaction
The given chemical equation is,
$6{{\text{H}}_{\text{2}}}{\text{O}} + {\text{6C}}{{\text{O}}_2} \to {{\text{C}}_{\text{6}}}{{\text{H}}_{{\text{12}}}}{{\text{O}}_{\text{6}}} + 6{{\text{O}}_{\text{2}}}$
The above balanced chemical equation indicates that 6 moles of carbon dioxide is required to form one mole of glucose.
6 moles of $CO_2$ needed to form= 1 mole of glucose
So, 2 moles of $CO_2$ can produce =$\dfrac{1}{6} \times 2 = \dfrac{1}{3}\,{\text{mol}}$ of glucose
Now, we have to calculate the mass of glucose produced when 88 g of $CO_2$ is used using the below formula.
Number of moles=$\dfrac{{{\text{Mass}}}} {{{\text{Molar}}\,{\text{mass}}}}$
The moles of glucose produced is 1/3 mol and
The molar mass of glucose $\left( {{{\text{C}}_{\text{6}}}{{\text{H}}_{{\text{12}}}}{{\text{O}}_{\text{6}}}} \right)$
=$6 \times 12 + 12 \times 1 + 6 \times 16 = 72 + 12 + 96 = 180\,{\text{g}}\,{\text{mo}}{{\text{l}}^{ - 1}}$.
So, Mass of glucose produced=$\dfrac{1} {3} \times 180 = 60\,{\text{g}}$

Hence, the mass of glucose produced is 60 g.

Note: It is to be remembered that glucose is a monosaccharide that is formed by plants and algae during the process of photosynthesis. Glucose provides energy to all living organisms. Glucose is stored as glycogen in animals and as amylopectin and starch in plants.