Question

1. in the carbon cycle, list at least 3 ways co₂ gets into of the atmosphere:

a. how does co₂ get out of the atmosphere?

Explanation:

For how \( \text{CO}_2 \) gets into the atmosphere:

1. Respiration: Living organisms (plants, animals, fungi, etc.) perform cellular respiration, where glucose is broken down, and \( \text{CO}_2 \) is released as a by - product. The chemical equation for aerobic respiration is \( \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2

ightarrow6\text{CO}_2+6\text{H}_2\text{O}+\text{Energy} \).

1. Combustion: The burning of fossil fuels (coal, oil, natural gas) for energy production, transportation, and heating releases large amounts of \( \text{CO}_2 \). For example, when coal (mostly carbon, \( \text{C} \)) burns, the reaction is \( \text{C}+\text{O}_2

ightarrow\text{CO}_2 \) (in complete combustion). Also, the burning of biomass (like wood) in wildfires or for fuel also releases \( \text{CO}_2 \).

1. Decomposition: When organic matter (dead plants, animals, waste) decomposes, decomposers (bacteria, fungi) break down the organic compounds, and \( \text{CO}_2 \) is released back into the atmosphere.

For part (a) (how \( \text{CO}_2 \) gets out of the atmosphere):

1. Photosynthesis: Plants, algae, and some bacteria use light energy to convert \( \text{CO}_2 \) and water into glucose and oxygen. The chemical equation is \( 6\text{CO}_2 + 6\text{H}_2\text{O}\xrightarrow{\text{Light Energy}}\text{C}_6\text{H}_{12}\text{O}_6+6\text{O}_2 \).
2. Ocean Uptake: The ocean acts as a carbon sink. \( \text{CO}_2 \) dissolves in the ocean water, forming carbonic acid (\( \text{H}_2\text{CO}_3 \)) and related ions (bicarbonate, \( \text{HCO}_3^- \); carbonate, \( \text{CO}_3^{2 - } \)). Some of the dissolved \( \text{CO}_2 \) is also used by marine organisms (like corals and shell - forming organisms) to build their calcium carbonate shells and skeletons.

Answer:

• Ways \( \text{CO}_2 \) gets into the atmosphere: Respiration, Combustion (of fossil fuels and biomass), Decomposition.
• (a) Ways \( \text{CO}_2 \) gets out of the atmosphere: Photosynthesis, Ocean Uptake (dissolution and use by marine organisms).