Question

How much carbon dioxide is exhaled if an animal inhales 32.0 g ${{\text{O}}_{2}}$?

Answer 1

During the respiration process, oxygen is inhaled from the air and after going inside our body the cells use this oxygen to breakdown the glucose to release energy and the reaction involved is as follows –

& {{\text{C}}_{6}}{{\text{H}}_{12}}{{\text{O}}_{6}}+6{{\text{O}}_{2}}\to 6\text{C}{{\text{O}}_{2}}+6{{\text{H}}_{2}}\text{O}+\text{Energy} \\\ & \text{GLUCOSE}+\text{OXYGEN}\to \text{CARBON}\text{ DIOXIDE}+\text{WATER}+\text{ENERGY} \\\ \end{aligned}$$ The side product of this reaction is carbon dioxide which is then exhaled by our body. The amount of $\text{C}{{\text{O}}_{2}}$ exhaled can be calculated by the stoichiometry of this reaction. **Complete step by step answer:** Breathing is the sign that we are alive and it involves the process of inhaling oxygen from the air and exhaling carbon dioxide back into the air. To find out the amount of $\text{C}{{\text{O}}_{2}}$ exhaled we first need to know how this carbon dioxide forms in our body to be exhaled out. During breathing, we inhale oxygen from the atmosphere. This inhaled air reaches the lungs and enters alveoli (tiny air sacs at the end of the lungs). Here, oxygen diffuses out from alveoli into the blood. In the blood, cells use this oxygen to breakdown large molecules such as carbohydrates and glucose to produce ATP molecules which are the source of energy for the body cells to execute various body functions. The reaction involved in the process is given below – $$\begin{aligned} & {{\text{C}}_{6}}{{\text{H}}_{12}}{{\text{O}}_{6}}+6{{\text{O}}_{2}}\to 6\text{C}{{\text{O}}_{2}}+6{{\text{H}}_{2}}\text{O}+\text{Energy} \\\ & \text{GLUCOSE}+\text{OXYGEN}\to \text{CARBON DIOXIDE}+\text{WATER}+\text{ENERGY} \\\ \end{aligned}$$ The side product of this reaction is carbon dioxide. Now, the carbon dioxide rich blood will return to the heart and then be pumped into the lungs. Then, in the lungs, carbon dioxide will be exhaled while we breathe. This cycle of inhaling oxygen and exhaling carbon dioxide repeats itself every time we breathe. \- Calculation to find the amount of $\text{C}{{\text{O}}_{2}}$ produced when 32 g of ${{\text{O}}_{2}}$ is inhaled: From the above reaction, we can see that 6 moles of oxygen are used up by a glucose molecule to produce 6 moles of carbon dioxide. $\therefore $ 1 mole of oxygen will produce 1 mole $\text{C}{{\text{O}}_{2}}$. Now, 1 mole ${{\text{O}}_{2}}=32.0\text{ g}$ and, 1 mole $\text{C}{{\text{O}}_{2}}=44.0\text{ g}$ Thus, oxygen will produce 44.0 g carbon dioxide. Hence, if an animal inhales 32.0 g oxygen then it will exhale 44.0 g carbon dioxide. **Note:** The process of breathing and respiration are two different things. Breathing is a physical phenomenon that involves inhaling oxygen and exhaling carbon dioxide gas with the help of our lungs. While respiration is a chemical process that takes place inside our cells through which energy is being produced with the help of inhaled air for performing various life functions and the carbon dioxide forms as a side product in this process.