Substances

Expected Learning : to recognise that there are many different types of substances that

are in use and to group substances into different categories

Substances

• There are many different types of materials and substances that we use in our everyday lives.

• For example;• glass in windows• rubber in car tyres• detergents for washing up

Groups of substances

• Substances can be placed into groups depending on a number of characteristics or properties. Some of the groups that we can use to place substances into are:

• elements• metals• non-metals• compounds• naturally occurring substances• synthetic substances

Small Group activity

• Write down the names of 15 different substances.

• Try to group these substances into some of the above groups.

• Can you think of any other groups that you could have used?

Grouping Substances

• Substances can be grouped into many different groups based on Chemical and Physical properties.

Physical properties of substances

• Physical properties of a substances include the texture, shape, size, color, odor, volume, mass, weight, and density

• Physical change reactions occur when substance changes its property but still stays the same substance.

Physical Change reaction

Chemical properties

• Chemical properties of a substance describes its "potential" to undergo some chemical change or reaction .

• Whenever a chemical change has occurred a new chemical substance has been formed. A chemical reaction has occurred. In chemical reactions atoms are not created or destroyed but are rearranged to form the new substances.

If you add two substances together sometimes you get a chemical reaction. This is when a new substance is made.

It is very difficult to reverse the reaction and get the original substances back.

Signs that a chemical reaction has taken place include a change in colour, heat being given off or bubbles of gas being made.

Fireworks -Chemical change reaction

• A chemical change occurs when fireworks are used. Fireworks are made of metals such as magnesium and copper. These change chemically as they light up the sky.

Adding acid to alkali

Fireworks Driving a car

Ice cream melting

Boiling the kettle frying an egg

Burning a candle Melting candle wax

Dissolving sugar in tea

Lighting a matchMaking ice cubes

Ironing clothes

Printing Baking a cake Launching a space rocket

Discuss in pairs which of these are chemical reactions

x x

x x

xx

x

The changes that are not chemical changes are called physical changes

Double Bubble!

Chemical

Reactions

Physical Reaction

s

KEY WORDSIrreversibleReversible

Product

Chemical

Reactions

Physical Reaction

s

Is it a chemical or physical change?

• Sugar dissolving in tea

•Chemical Change

•Physical Change

OOPS!

Did it change size, color, shape (Physical Change)?

orDid it become different matter (Chemical

Change)?

Correct!

Is it a chemical or physical change?

• Logs burning

•Chemical Change

•Physical Change

OOPS!

Did it change size, color, shape (Physical Change)?

orDid it become different matter (Chemical

Change)?

Correct!

Is it a chemical or physical change?

• Breaking water up by separating it into hydrogen and oxygen

•Chemical Change

•Physical Change

OOPS!

Did it change size, color, shape (Physical Change)?

orDid it become different matter (Chemical

Change)?

Correct!

Is it a chemical or physical change?

• Cutting paper

•Chemical Change

•Physical Change

OOPS!

Did it change size, color, shape (Physical Change)?

orDid it become different matter (Chemical

Change)?

Correct!

Is it a chemical or physical change?

• Crushing an aspirin

•Chemical Change

•Physical Change

OOPS!

Did it change size, color, shape (Physical Change)?

orDid it become different matter (Chemical

Change)?

Correct!

Is it a chemical or physical change?

• Metal rusting

•Chemical Change

•Physical Change

OOPS!

Did it change size, color, shape (Physical Change)?

orDid it become different matter (Chemical

Change)?

Correct!

Is it a chemical or physical change?

• Lighter fluid burining

•Chemical Change

•Physical Change

OOPS!

Did it change size, color, shape (Physical Change)?

orDid it become different matter (Chemical

Change)?

Correct!

Is it a chemical or physical change?

• An egg rotting

•Chemical Change

•Physical Change

OOPS!

Did it change size, color, shape (Physical Change)?

orDid it become different matter (Chemical

Change)?

Correct!

Is it a chemical or physical change?

• An egg breaking

•Chemical Change

•Physical Change

OOPS!

Did it change size, color, shape (Physical Change)?

orDid it become different matter (Chemical

Change)?

Correct!