Is Carbon Dioxide a Pure Substance?

By Staff WriterLast Updated Apr 4, 2020 3:51:40 PM ET
Carbon Dioxide
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Carbon dioxide is a compound that consists of two atoms of oxygen and an atom of carbon. Pure substances don’t have to be mixed and cannot be broken down without complex processes. Because carbon dioxide is natural and can’t be broken down easily, it’s a pure substance.

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The Air We Breathe

We take in oxygen from the air when we breathe, and we also release carbon dioxide. The air we breathe is made up of several substances. We tend to think of oxygen as being the main component of air because our bodies need it to live, but oxygen is just a small part of the makeup of air. Actually, 78 percent of the air that we breathe is nitrogen, while another 21 percent is oxygen.

Other gases make up what’s left of the chemical composition of air. Argon, methane, helium, krypton, hydrogen, xenon, and iodine are present in small amounts. You can find small amounts of compounds in air as well. Carbon dioxide is in the air we breathe, along with ozone, nitrogen dioxide, and a trace amount of carbon monoxide. There are also small amounts of water vapor in the air we breathe.

The Exchange of Oxygen and Carbon Dioxide

When we breathe, we’re getting the oxygen we need from the air to survive. The cells in our body use oxygen to create energy. As we take air into our lungs, millions of tiny sacs called alveoli take the oxygen in. The walls of the alveoli are thin enough to release the oxygen into our bloodstream, and our blood carries oxygen throughout our body.

The energy that our bodies expend creates carbon dioxide, so the breathing process works in reverse to remove the carbon dioxide from our bodies. Our blood carries carbon dioxide back to the lungs, where we release it as we exhale.

How Plants and Trees Help Us Breathe

Plants and trees help us with the exchange between carbon dioxide and oxygen during the day by doing the reverse of what humans do. Plants don’t exactly breathe like we do because they don’t have lungs, but what they do is a process called photosynthesis and respiration.

At night, plants take in oxygen and release carbon dioxide just like we do. During the day, plants use the light of the sun to take in carbon dioxide to create nutrients. They release oxygen back into the atmosphere. This process is why plants are so important for human survival because they produce so much of the oxygen we need to survive.

Carbon Dioxide and Pollution

Even though carbon dioxide occurs naturally and is an important part of the life of plants, there’s a definite relationship between carbon dioxide and pollution. Much of the pollution in our atmosphere occurs because of too much carbon dioxide that factories and fossil fuel burning transportation creates.

Proponents of climate change believe that eliminating carbon dioxide from the atmosphere will prevent warming of the planet. Environmentalists believe that changing the fuels we use will help cut down on the carbon dioxide that we release into the atmosphere.

Other Forms of Carbon Dioxide

Carbon dioxide is a gas, and we can’t see or taste it when we breathe air. But we can witness carbon dioxide in other forms. The fizz in soft drinks, sparkling wine, and some types of beer comes from carbon dioxide. The bubbles and fizz are the effects of the carbon dioxide as it’s released back into the air, and it’s why we refer to these type of drinks as carbonated beverages.

If you’ve seen dry ice, you’ve witnessed another form of carbon dioxide. Dry ice is frozen carbon dioxide, and it’s so cold that the air that hits it condenses and creates fog, which is why we see it used to create fog and haze for plays and concerts. At the coldest temperature of all time in Antarctica in 1983, carbon dioxide turned into snow, and space scientists have made a note of carbon dioxide snow on Mars as well.