2 (f.c.a) CO2 in Earth's Atmosphere
Carbon Dioxide makes up less than 1 percent of the Earth’s atmosphere. Carbon dioxide is not an element like oxygen and nitrogen. It is a compound because it is made of a carbon atom and two oxygen atoms. The carbon and oxygen are chemically bonded in a 2-1 ratio. Compounds cannot be separated by physical means. However compounds can by broken down through a chemical change. Photosynthesis is a chemical change where plants break down carbon dioxide. Sugar and oxygen are new substance in this reaction.
Carbon Dioxide Each molecule of carbon dioxide has one atom of carbon and two atoms of oxygen. Carbon dioxide is essential to life. Plants must have carbon dioxide to produce food. When the cells of plants and animals break down food to produce energy, they give off carbon dioxide as a waste product.
When fuels such as coal and gasoline are burned, they release carbon dioxide. Burning these fuels increases the amount of carbon dioxide in the atmosphere.
All matter is made of elements, but most elements in nature are found combined with other elements. A compound is a pure substance made of two or more elements chemically combined in a set ratio. A compound may be represented by a chemical formula, which shows the elements in the compound and the ratio of atoms. For example, part of the gas you exhale is carbon dioxide. Its chemical formula is CO2. The number 2 below the symbol for oxygen tells you that the ratio of carbon to oxygen is 1 to 2. (If there is no number after the element’s symbol, the number 1 is understood.)
When elements are chemically combined, they form compounds having properties that are different from those of the uncombined elements. Table sugar (C12H22O11) is a compound made of the elements carbon, hydrogen, and oxygen. The sugar crystals do not resemble the gases oxygen and hydrogen or the black carbon you see in charcoal.
Carbon Dioxide Each molecule of carbon dioxide has one atom of carbon and two atoms of oxygen. Carbon dioxide is essential to life. Plants must have carbon dioxide to produce food. When the cells of plants and animals break down food to produce energy, they give off carbon dioxide as a waste product.
When fuels such as coal and gasoline are burned, they release carbon dioxide. Burning these fuels increases the amount of carbon dioxide in the atmosphere.
All matter is made of elements, but most elements in nature are found combined with other elements. A compound is a pure substance made of two or more elements chemically combined in a set ratio. A compound may be represented by a chemical formula, which shows the elements in the compound and the ratio of atoms. For example, part of the gas you exhale is carbon dioxide. Its chemical formula is CO2. The number 2 below the symbol for oxygen tells you that the ratio of carbon to oxygen is 1 to 2. (If there is no number after the element’s symbol, the number 1 is understood.)
When elements are chemically combined, they form compounds having properties that are different from those of the uncombined elements. Table sugar (C12H22O11) is a compound made of the elements carbon, hydrogen, and oxygen. The sugar crystals do not resemble the gases oxygen and hydrogen or the black carbon you see in charcoal.
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