Introductory Chemistry Year 8

Chemical and Physical Changes

Some changes are obvious- growing plants, baking cakes
Some changes are less obvious- paint fading on an outside wall
Some changes are reversible, and others irreversible
All changes can be explained by Particle Theory, which states that all matter is made up of particles. These particles are constantly moving, and attracted to one another.
These particles are arranged in different ways, giving the substance its state of either solid, liquid or gas.

Match

Match the particle arrangement with the state

solid

liquid

gas

• solid

• liquid

• gas

Matter expands upon heating

This is because the heat causes the particles to vibrate more, as they do, they need more space, thus the material made up of the particles expands.
Sometimes the expansion can cause the substance to go into liquid state.
Upon further heating, the attraction between the particles breaks down, and the substance becomes a gas

Drag and Drop

When a solid is heated, the particles​

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more . This means that the solid will​

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to accommodate this extra movement.

Drag these tiles and drop them in the correct blank above

vibrate

expand

shake

contract

grow

Match

Match the change of state with the correct term

• solid --> liquid

• liquid --> gas

• gas --> liquid

• liquid --> solid

• solid --> gas

melting

evaporation

condensation

freezing

sublimation

• melting

• evaporation

• condensation

• freezing

• sublimation

Physical Changes-

-are reversible
-usually involve a change of state
-can involve temperature changes like the addition of heat
-can involve the addition of a solvent, in which case the substance dissolves, becoming a solute in a solution

Labelling

Label the diagram with the terms provided

Drag labels to their correct position on the image

solution

solvent

solute

Chemical Changes

​Produce new substances!!!

A chemical change has taken place IF one or more of the following is produced
-heat -gas -a solid (precipitate)
-light -colour change
-sound -temperature change

Chemical Changes

​Rearrange atoms- the building blocks of matter

All matter is made up of atoms.
When different atoms combine, they become compounds
All known atoms have been arranged into a Periodic Table, first put together by Dmitri Mendeleev

Match

Use the periodic table given to you, to match the element with its symbol

• Sodium

• Hydrogen

• Oxygen

• Carbon

• Iron

Na

H

O

C

Fe

• Na

• H

• O

• C

• Fe

Categorize

Options (16)

copper

aluminum

iron

gold

silver

lead

zinc

platinum

oxygen

nitrogen

sulfur

phosphorus

chlorine

carbon

helium

neon

Use the periodic table to categorize the element as either metal or non-metal

metal

non metal

Reorder

Reorder the following elements in increasing atomic number

• lithium

• beryllium

• boron

• carbon

• nitrogen

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

Reorder

Reorder the following elements in increasing atomic number

• helium

• neon

• argon

• krypton

• xenon

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

Match

Can you name the following familiar compounds/elements from their formula? Use the periodic table to help you

• H₂O

• CO₂

• N₂

• He

• O₂

water

carbon dioxide

nitrogen

helium

oxygen

• water

• carbon dioxide

• nitrogen

• helium

• oxygen

Poll

In today's lesson we looked at

• physical changes

• what makes a chemical change

• particle theory of matter

• elephants

Poll

We learned that

• physical changes are reversible

• chemical changes produce new substances

• the periodic table is made up of elements

• all elements are solids

Poll

We also learned that

• compounds are formed when two or more atoms combine

• krypton is a gas

• some symbols don't make sense

• allotropes are the same element, but different arrangement of atoms