8.2 The Chemical Earth

The Three States of MatterMatter can be in one of three “states”. The three states of matter are SOLIDS,

LIQUIDS and GASES.

What are their properties?

Solid Liquid Gas

Very difficult to squash, can’t be poured

Difficult to squash, can be poured

Easy to squash, can be poured

Particle theoryParticle theory is all about explaining the properties of solids, liquids and gases by looking at what the particles do.

In a solid the particles ______ around a _____ position. There is a ______ force of attraction between each particle and they are very _____ together

SOLIDS

Words to use – strong, close, vibrate, fixed

LIQUIDS

GASES

In a liquid the particles are _____ together but can move in ____ direction. They won’t keep a _____ shape like _____ do.

In a gas the particles are ____ far apart and move _____ in all directions. They often ______ with each other and because they are far apart they can be easily _______.

Words – fixed, collide, any, quickly, close, very, solids

Changes of StateChanges of state occur when one state of matter (i.e. solid, liquid or gas) is changed into another…

1) If enough energy is supplied to a solid the particles will break free from their fixed positions and the solid will become a…

2) If even more energy is supplied to the liquid the bonds will be completely broken and the liquid will turn into a…

3) A gas can be turned straight back into a solid, but this is very rare

Changes of StateWhat are these processes called? Choose from freezing, evaporating, melting, condensing

Match up these definitions:Freezing

Melting

Evaporating

Condensing

Diffusion

A change of state – liquid to gas

A change of state – gas to liquid

This is when a smell “spreads out” across a room

A change of state – solid to liquid

A change of state – liquid to solid

AtomsAtoms are the “building blocks” of all matter and are the simplest form of molecule. They are all made up of protons, neutrons and electrons. They look something like this:

The Nucleus – this contains neutrons and protons

Electrons – these orbit around the nucleus

Classifying Matter

Matter

Pure Substances Mixtures

Elements Compounds Homogenous Heterogeneous

metals nonmetals ionic covalent

Na Cl2 NaCl NO2

NaCl(aq) granite

tea pineapple juice

Au I2 NH4Cl C12H22O11

ElementsIf 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:

These atoms are ALL iron – there’s nothing else in here

CompoundsCompounds are different to elements. They contain different atoms. Here are some examples:

Glucose

MethaneSodium chloride (salt)

Making compoundsCompounds are made when two or more elements (or compounds) go through

a chemical reaction.

For example:

1) When carbon reacts with oxygen it usually forms ____ _________

2) When oxygen reacts with hydrogen it could form ______

3) When iron reacts with oxygen it could form ______ ______

Water, iron oxide or carbon dioxide?

Some simple compounds…

Methane, CH4Water, H2O

Carbon dioxide, CO2

Ethyne, C2H2

Sulphuric acid, H2SO4

Key

Hydrogen

Oxygen

Carbon

Sulphur

Naming compoundsRule 1 – When two elements join the end is usually _______ide.

e.g. Magnesium + oxygen magnesium oxide

1) Sodium + chlorine

2) Magnesium + fluorine

3) Lithium + iodine

4) Chlorine + copper

5) Oxygen + iron

6) KBr

7) LiCl

8) CaO

9) MgO2

10) KF

Naming compoundsRule 2 – When three or more elements combine and one of them is oxygen the

ending is _____ate

e.g. Copper + sulphur + oxygen Copper sulphate

1) Calcium + carbon + oxygen

2) Potassium + carbon + oxygen

3) Calcium + sulphur + oxygen

4) Magnesium + chlorine + oxygen

5) Calcium + oxygen + nitrogen

6) AgNO3

7) H2SO4

8) K2CO3

Naming compoundsRule 3 – If two identical elements combine then the name doesn’t change

This happens with the following elements:

1) H2

2) N2

3) O2

4) F2

5) Cl2

6) Br2

These elements always go around in pairs. For example, hydrogen looks like this:

MixturesA mixture is a “collection” of different elements and compounds. For example, consider salt dissolving in water:

Before After

The Earth

Read section 1.3 to end of 1.5 of conquering chemistry and:1.Draw a diagram of the layers of the Earth (and describe the spheres: Lithosphere, Hydrosphere, Atmosphere)2.Draw a table the describe the layers mentioned above and examples of mixtures found in each.