Chemistry 8.2 – The Chemical Earth

8.2.1 – Chemical equations and formulae, % composition, separation techniques, nomenclature
The living and non-living components of the Earth contain mixtures
Readings Knowledge and skills Notes/ Resources/ Activities
Context: p.
CC1: p. 41-43
CC1 4th Ed: p.33-34 8.2.3A1 identify that matter is made of particles that are continuously moving and interacting All matter is made up of particles
In solids – vibrating slightly, packed closely together, causes definite shapes of solids, cannot be compressed much
In liquids – not confined to vibration but also random translation, move more freely/possess more kinetic energy, no definite shape/take shape of container, cannot be compressed much
In gases - rapid random motion, no significant forces in between, causes gases to spread quickly to fill whole volume, easily compressed
Context: p.
CC1: p.5-9, 43-45, 47-48
CC1 4th Ed: p.5-8, 35-36, 38-39 A3 identify the difference between elements, compounds and mixtures in terms of particle theory Elements – a group (≥2) of one type of atom, e.g. a gold flake, a pure substance which cannot be decomposed into simpler substances
Compounds – a substance made of ≥2 elements, a pure substance which can be decomposed into simpler substances, for example into elements.
Mixtures – made of many compounds and elements, an impure substance (one substance contaminated with small amounts of one or more other substances)

Molecules – size of an atom, compound or element (generally small, the smallest particle of a substance that is capable of separate existence. E.g. Water (see picture)

Monatomic molecules – contain one atom, the noble gases helium, neon, argon, krypton, xenon and radon; exist as independent atoms, therefore monatomic.
Diatomic molecule – contain two atoms, all common gaseous elements aside from the noble gases

8.2.3A8 describe molecules as particles which can move independently of each other 8.2.3A9 distinguish between molecules containing one atom (the noble gases) and molecules with more than one atom
Context: p.
CC1: p. 7-8, 21-24
CC1 4th Ed: p.7,20-22, 8.2.5A1 identify differences between physical and chemical properties of elements, compounds and mixtures The properties of a substance (element, compound or mixture) vary according to the electronic structures of the atoms involved. This in turn affects the strength of the bongs within and between the respective molecules.
Physical Properties – how the substance changes its structure or state as a result of it physical surrounding e.g. MP, BP, state, solubility
Chemical properties – how the substance chemically reacts (or decays) changing its chemical makeup. Occurs as a result of chemical reactions, irradiation or nuclear decay. E.g. flammability, heat capacity
Element – distinctive properties for most elements
Compound – has properties that are different from the elements which make it up
Mixture – properties vary with composition 8.2.5B1 perform a first-hand investigation to compare the properties of some common elements in their elemental state with the properties of the compound(s) of these elements (eg magnesium and oxygen) Prac: Comparing properties of elements and compounds
Aim: To compare the properties, specifically mass, of Elements (magnesium) and compounds (magnesium oxide)

Result : After the element magnesium forms the compound magnesium oxide due to heat, there was an increase in mass, demonstrating that the change in physical properties. A8 identify IUPAC names for carbon compounds as they are encountered (integrated throughout the course especially in the Energy Topic)

Name Methane Ethanol
Formula CH4 C2H5OH

A2 gather and present information from first-hand or secondary sources to write equations to represent all chemical reactions encountered in the Preliminary course (integrated throughout the course)
Metals and non-metals (ionic compounds) – name the metal