Mixtures

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Mixtures

Compounds
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What is a Compound?
A compound is a substance consisting of two or
more elements chemically combined together.
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Some Examples of Compounds (Textbook pg 78)
SodiumChlorine
HydrogenOxygen
CopperSulphur Oxygen
CarbonOxygen
Their constituent elements
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Characteristics of Compounds
(Textbook pg 81-83)

1. A compound has properties that are different from
   the properties of its constituent elements.

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Characteristics of Compounds

1. When a compound is formed, there is usually an
   exchange of energy (in the form of heat energy or
   light energy or both) with the surroundings.

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Characteristics of Compounds

• A compound can only be broken down into simpler
  substances by chemical methods, such as
  decomposition by heat energy, exposure to light
  or passing an electric current through it.)

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Characteristics of Compounds

1. The different elements in a compound always join
   together in a fixed proportion by mass.

For example, 1 g of hydrogen combines with only 8
g of oxygen to form 9 g of water.
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Test Yourself
Explain why water is a compound?
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What is a Mixture? A mixture consists of two or
more substances not chemically combined together.
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Some Examples of Mixtures

• air
• soil
• blood
• sea water
• aerated water

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Characteristics of Mixtures

1. A mixture has the properties of its components.

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Characteristics of Mixtures

1. When a mixture is produced, little or no energy
   in the form of heat energy or light energy is
   given out or taken in.

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Characteristics of Mixtures

1. A mixture can be separated into its components by
   physical means such as using a magnet,
   evaporation, filtration and distillation.

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Characteristics of Mixtures

1. The components in a mixture can be mixed in any
   proportion by mass.

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Test Yourself
Explain why air is a mixture?
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Difference between Elements, Compounds and
Mixtures
Elements Compounds Mixtures
Made up of only one kind of atom Different elements in a compound combine in a fixed proportion by mass. The components in a mixture are not mixed in any fixed proportion.
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Elements Compounds Mixtures
An element is the simplest pure substances A chemical change takes place when a compound is formed. No chemical reaction occurs. There is little or no light or heat taken in or given out.
Elements have properties similar to those of their atoms. A compound has properties which are different from the properties of its constituent elements. A mixture has the properties of the substances of which it is made.
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Elements Compounds Mixtures
Elements cannot be broken down. A compound can only be broken down, by chemical methods, for example. Heating (decomposition) or by passing electricity through it. A mixture can be separated easily by physical methods, for example, filtration, distillation, evaporation.
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Word Equations are commonly used for representing
chemical reactions.
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Word Equations are commonly used for representing
chemical reactions.
3. oxygen hydrogen
4. iron hydrochloric acid