Common Chemicals and their place in everyday life

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Common Chemicals and their place in everyday life

• Lesson 9

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• Breathe in a lungful of air, think about the
  billions of molecules that you are inhaling. Air
  is mostly nitrogen and oxygen, but you are
  breathing in a mixture that contains other gases
  as well.

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Nitrogen (N2)

• Two atoms of the element nitrogen combine to form
  a molecule of the gas nitrogen. Nitrogen makes up
  approximately 78 of the atmosphere. It is not
  very reactive, which means we can breathe it in
  safely without causing chemical changes in our
  lungs.

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• However, under certain conditions, such as in a
  car engine, nitrogen gas reacts with oxygen to
  produce nitrogen dioxide (NO2), a very toxic
  red-brown gas. Nitrogen dioxide in low
  concentrations causes the yellow haze of air
  pollution that can be seen in some cities.

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Argon (Ar)

• Argon atoms do not combine with other atoms to
  form molecules. As a result, argon gas is
  composed of single atoms of argon. Almost all of
  the argon in the atmosphere has leaked out from
  inside the Earth. The gas is completely harmless
  and quite useful, especially for filling electric
  light bulbs and fluorescent tubes.

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Oxygen (O2 and O3)

• Atoms of the element oxygen can combine to form
  two different molecules. The more common of these
  of these contains two atoms of oxygen. This is
  the form that takes up about 21 of the air that
  you breathe and is what we commonly call oxygen
  gas. Almost all organisms need oxygen to
  survive, as it is used in cellular respiration.

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• The less common oxygen molecule, called ozone
  (O3), contains three atoms of oxygen. Ozone
  absorbs most of the Ultraviolet radiation from
  the Sun.

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Carbon dioxide (CO2) and Carbon monoxide (CO)

• Two atmospheric gases contain only atoms of
  carbon and oxygen.
• Carbon dioxide is necessary for life on earth.
  Carbon monoxide is extremely dangerous poisonous
  to animals.

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• When fossil fuels burn, the two gases produced
  are CO2 and water (H2O). When there is not
  enough oxygen present CO is also produced. Since
  CO is very similar to O2 in its shape it is
  incredibly dangerous as it takes O2 place when it
  enters the lungs.

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Combining capacities of atoms

• Bond- a connection between atoms.

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Carbon 4 bonds Hydrogen 1 bond
Nitrogen 3 bonds Halogens 1 bond
Oxygen 2 bonds Sulfur 2 bonds
Phosphorous 3 bonds
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• Lab Activity Building Molecules