8.2 The Chemical Earth

The Three States of Matter Matter can be in one of three “states”. The three states of matter are SOLIDS, LIQUIDS and GASES. What are their properties? SolidLiquidGas Very difficult to squash, can’t be poured Difficult to squash, can be poured Easy to squash, can be poured

Particle theory Particle 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 State Changes 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 State What 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

Atoms Atoms 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 SubstancesMixtures Elements CompoundsHomogenousHeterogeneous metalsnonmetalsioniccovalent NaCl 2 NaClNO 2 NaCl (aq) granite teapineapple juice AuI2I2 NH 4 ClC 12 H 22 O 11

Elements If 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

Compounds Compounds are different to elements. They contain different atoms. Here are some examples: Glucose Methane Sodium chloride (salt)

Making compounds Compounds 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, CH 4 Water, H 2 O Carbon dioxide, CO 2 Ethyne, C 2 H 2 Sulphuric acid, H 2 SO 4 Key Hydrogen Oxygen Carbon Sulphur

Naming compounds Rule 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)MgO 2 10)KF

Naming compounds Rule 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)AgNO 3 7)H 2 SO 4 8)K 2 CO 3

Naming compounds Rule 3 – If two identical elements combine then the name doesn’t change This happens with the following elements: 1)H 2 2)N 2 3)O 2 4)F 2 5)Cl 2 6)Br 2 These elements always go around in pairs. For example, hydrogen looks like this:

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

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.