University:
Felician University
Course:
CHEM-001 | Basic Chemistry
Academic year:

2020
Views:

492

Pages:

1
Author:

Clint W.

CARBON CyCLING Carbon Cycle Organic Conversions CO2 Autotrophs convert atmospheric carbon dioxide into organic compounds via the process of photosynthesis • Equation (balanced): 6CO2 + 6H2O → C6H12O6 + 6O2 Photosynthesis Respiration Heterotrophs obtain organic compounds via feeding Feeding MACHINES ANIMALS PLANTS OCEAN Combustion The breakdown of organic compounds via cell respiration (to produce ATP) releases carbon dioxide as a by-product • Equation (balanced): C6H12O6 + 6O2 → 6CO2 + 6H2O Decomposition FUELS FOSSILS CO2 CO2 CaCO3 CARBON COMPOUNDS Fossil Fuels PHOTOSYNTHESIS In aerobic conditions, saprotrophic bacteria will break down organic material and return it to the soil (i.e. decomposition) In anaerobic conditions, decomposition is prevented as the saprotrophic bacteria cannot function effectively • Anaerobic respiration will produce organic acids (⬇ ph) Peat / Coal • Organic matter that is not fully decomposed in anoxic or acidic soils will become peat • When peat is compressed under layers of sediment, heat and pressure remove moisture to transform it into coal Oil / Natural Gas • When marine organisms are buried under sediment on the ocean floor, compaction and anaerobic conditions transform the organic matter into oil and natural gas Combustion Hydrocarbons undergo combustion in the presence of O2 • The reaction is exergonic and CO2 and H2O is produced Sources of hydrocarbons include: • Fossilised organic matter (i.e. coal, oil and gas) • Biomass (e.g. bioethanol and biofuels) The energy produced by combustion reactions is typically used to power industrial processes • The combustion of fossil fuels is responsible for a significant increase in atmospheric CO2 concentrations CELL RESPIRATION Aquatic Conversions In aquatic ecosystems, carbon dioxide may remain dissolved in water or alternatively form hydrogen carbonate ions Animals may combine the carbonate ions with calcium to form hard shells (e.g. mollusca) and exoskeletons (e.g. coral) Carbonate ions may also interact with rock and sediment to form limestone Methane Production Methane (CH4) is produced from organic compounds by methanogenic archaeans This requires anaerobic conditions (commonly found in wetlands, marine sediments or digestive tract of ruminants) Methane diffuses into the air or forms deposits underground • In the air, methane is oxidised to form CO2 and H2O H H C O H OXYGEN C H O Methane Carbon Dioxide H H O Water (vapor)