Compounds and Mixtures

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Compounds and Mixtures
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Elements and compounds.

• Learning Objectives
• To be able to identify the differences between
  elements and compounds.
• To be able to give name to compounds that are
  formed.

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Elements
If a solid, liquid or gas is made up of only one
type of atom we say it is an element. For
example, consider a tripod made up of iron
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Compounds
Compounds are different to elements. They
contain different atoms. Here are some examples
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Some simple compounds
Carbon dioxide, CO2
Water, H2O
Ethyne, C2H2
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Making compounds

• Compounds are made when two or more elements (or
  compounds) go through a chemical reaction.
• For example
• When carbon reacts with oxygen it usually forms
  ____ _________
• When oxygen reacts with hydrogen it could form
  ______
• When iron reacts with oxygen it could form ______
  ______
• There are usually tell-tale signs to show when
  a compound is being made, such as bubbling, heat
  given off, colour changes, fizzing etc.

Water, iron oxide or carbon dioxide?
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Naming compounds
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Naming compounds
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Naming compounds
Rule 3 If two identical elements combine then
the name doesnt change
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Mixtures
Before
After
100 g
105 g
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Element, mixture or compound?
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Air
Air is a mixture
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18
79
79
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Separating air
Air can be separated into the different gases
that make it up. To do this you first have to
cool air down to -2000C and turn it into a liquid