Besides the difference in the number of oxygen molecules in carbon dioxide (CO2) and carbon monoxide (CO), what else can you say about the comparison of CO2 Vs CO?
These two compounds are the most common and recognized oxides carbon forms with oxygen. Carbon dioxide and carbon monoxide are important atmospheric gases that are essential contributors to the carbon cycle. However, they have different purposes in and outside of the laboratory.
This article is a comparison of CO2 vs CO. I’ll be highlighting the differences between these two compounds. You will also get to learn about the applications of these compounds and their similarities.
What is CO2?
CO2 is a covalent compound made of one carbon atom and two oxygen atoms. Carbon, a tetravalent atom, completes its valency by sharing covalent double bonds with the two oxygen atoms.
It is a stable gas at room temperature but is colorless and has a mildly sharp odor. CO2 is a universal source of carbon to the carbon cycle and life processes on Earth.
Although it is found in trace amounts (3 volumes in 10,000), CO2 is always present in the atmosphere and on the Earth.
There is a continuous addition and removal of CO2 in the atmosphere by biological processes such as photosynthesis and cellular respiration.
The Earth’s atmosphere used to contain 281 parts per million (ppm) CO2 but subsequent activities such as burning fossil fuels increased this amount to 421 ppm.
Additionally, CO2 is a key greenhouse gas and is responsible for global climate change. It creates the greenhouse effect in combination with methane, water vapor, and other gases.
What is CO?
CO is a flammable, toxic gas. It contains one carbon atom and one oxygen atom. The carbon shares a triple covalent bond with oxygen to complete its valency. CO is colorless and odorless gas but hazardous to living things and the environment.
This gas is a product of incomplete combustion of fuels and some gases. An accumulation of CO in the body depletes oxygen levels and causes poisoning.
Symptoms of CO poisoning include:
- Flu
- Headache
- Weakness and dizziness
- Nausea, sometimes accompanied by vomiting
- Shortness of breath
- Confusion
- Problems with the locomotor system
- Blurred vision
- Loss of muscle control
- Loss of consciousness
- Memory loss
Similarities between CO2 vs CO
- Both contain carbon and oxygen atoms
- Both gases are tasteless and colorless
- CO2 and CO are products of combustion and can become toxic but on different levels
- Also, they are both present in the atmosphere and we inhale them but in different concentrations
- CO2 and CO are linear molecules with a bond angle of 180° each
- In addition, they both have the same hybridization type
Differences between CO2 vs CO
Properties
In CO2, the carbon-to-oxygen ratio is 1:2. The central carbon atom shares two double covalent bonds with the oxygen atoms. This way, each atom has a complete valency with two sets of lone pair electrons on each oxygen atom.
CO has a carbon-to-oxygen ratio of 1:1. The carbon atom shares a triple covalent bond with the oxygen atom to complete its valency. Both atoms have one lone pair of electrons.
Furthermore, although both molecules have similar molecular geometry, bond angle, and hybridization, they have different bond lengths. CO2 has a bond length of 116.3 pm while CO has a bond length of 112.8 pm.
In addition, CO2 has a density of 1.977 kg/m3 when it is a gas at 1 atm and 32°F (0°C), 1,101 kg/m3 when it is a liquid at saturation -35°F (-37°C), and 1,562 kg/m3 when it is a solid at 1 atm and -109.3°F (-78.5°C).
It has a melting point of −69.9°F (-56.6°C) and a boiling point of -109.3°F (-78.5°C).
On the other hand, CO has a density of 1.145 kg/m3 at 1 atm and 77°F (25°C) when it is a gas and 1.250 kg/m3 at 0°C and 1 atm when in the liquid state. It has a melting point of -337.04°F (-205.02°C) and a boiling point of -312.7°F (-191.5°C).
Sources
CO2 is present in nature, but it can also be produced as an implication of certain activities and processes.
Some of the sources of CO2 include aerobic cellular respiration, breathing, volcanic eruption, combustion of organic matter, wood and fossil burning, oceanic release, and decomposition.
Other processes such as industrial fermentation, cement production, and increased deforestation can also increase the amount of CO2 in the atmosphere.
CO is not a product of natural processes. It is a man-made gas produced from gas combustion, smoke from cigarettes, burning of wood and fossil fuels, volcanoes, water heaters, broken heating systems, cookers, and gas fires.
Chemical reactions
CO has a high affinity for oxidation and undergoes oxidation reactions, unlike CO2 which has a low affinity for oxygen and does not undergo oxidation reactions.
Applications
CO2 is not toxic, which is why it finds various applications in the food and beverage industry. It is put to good use in the production of effervescent drinks and the preservation of fruits and vegetables.
Non-food uses are the production of fire extinguishers, dry ice, urea, and fertilizers. It is also useful in welding, pharmaceutical industries, and the promotion of plant growth in greenhouses.
CO is a toxic gas that finds more industrial uses such as the manufacture of other chemicals. It is used in the extraction of pure metals from metal ores, iron and steel manufacture, hydrogen production, petrochemical, and automotive industries.
However, CO is often used in food processing. Some industries use it in the preservation of fresh meat.
Detection
CO detectors are not the same as CO2 detectors. That is, a CO gas detector will not detect CO2. CO gas detectors use electrochemical sensors, gel sensors, and metal oxide semiconductors. CO2 detectors, on the other hand, use infrared sensors.
Also, CO is a less dense gas. The detectors are placed at high levels to detect the gas as it rises. Conversely, CO2 is a dense gas and will sink to the ground. Therefore, the detectors should be placed on the ground.
Hazards
CO is known as the more toxic gas. However, both gases can be hazardous when they are present in high concentrations.
CO2 causes the greenhouse effect which has a positive impact on the environment. However, high concentrations of CO2 increase the greenhouse effect and causes climate change which disturbs the ecosystem.
People who are exposed to high concentrations of CO2 experience suffocation, and anaphylaxis. CO has worse effects on human health. It displaces oxygen in the blood and results in CO poisoning.
Furthermore, the environmental impact of CO also affects human health indirectly. Although it does not contribute to global warming, it contributes to the amount of ground-level ozone which negatively impacts vegetation and human health.
FAQs
Can CO2 be converted to CO?
CO2 is converted into CO in a reduction reaction. This reaction uses a metal catalyst to reduce carbon dioxide to carbon monoxide. The catalyst is usually a heavy metal like zinc or iron.
Do cars emit CO or CO2?
CO and CO2 are two different emissions cars produce. CO is an air pollutant emission that is very toxic to the environment and living things. It causes smog and heart and lung diseases.
On the other hand, CO2 is a greenhouse gas emission responsible for the greenhouse effect and climate change.
Why is CO combustible and CO2 is not?
CO supports combustion and is flammable but CO2 does not support combustion and is not flammable because while the former supports oxidation reaction, the latter does not.
In addition, CO burns in oxygen in an exothermic reaction to form CO2. CO2, on the other hand, has a poor affinity for oxygen. It is a non-combustible gas and is very useful in the production of fire extinguishers.
Conclusion
CO2 and CO are two different compounds beyond the difference in the number of oxygen atoms in each. In terms of reactivity, CO2 is non-reactive while CO is highly reactive. Also, CO2 is a non-polar molecule. CO, on the other hand, is polar.
Furthermore, while CO2 is a naturally occurring gas that is essential for plant and animal life, CO is a toxic gas that is a by-product of incomplete combustion. CO2 finds application in the food and drinks industry while CO is only good for industrial processes.
You can also learn about the molecular geometry, hybridization, and polarity of CO2.
Thanks for reading.