substances expected learning : to recognise that there are many different types of substances that...
TRANSCRIPT
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!