1.20 understand the term molar volume of a gas and use its values (24 dm3 and 24,000 cm3) at room temperature and pressure (rtp) in calculations.

1 dm³ = 1000cm³

The best way to do these calculations is by using this triangle:

Molar Volume = 24dm³

Volume = moles x 24

moles = volume ÷ 24

24 = volume ÷moles

1.19 carry out mole calculations using relative atomic mass (Ar) and relative formula mass (Mr)

The simplest way to remember how to do these calculations is using this triangle:

Mass = Mr x Moles

Mr = Mass ÷ Moles

Moles = Mass ÷ Mr

1.18 understand the term mole as the Avogadro number of particles (atoms, molecules, formulae, ions or electrons) in a substance

A mole is 6.022 x 10²³ atoms of any element. This is Avogadro's number.

1.17 understand the use of the term mole to represent the amount of substance

A mole is a number just how a million is equal to 1,000,000 a mole is equal to 6.022 x 10²³

(This is also known as Avogadro's number)

1 mole of any element is equal to its RAM

e.g. water has a RAM of 18 and one mole of H2O weighs 18g

1.16 calculate relative formula masses (Mr) from relative atomic masses (Ar)

The Mr of a molecule or compound is calculated using this formula:

(Ar x number of that atom in molecule/compound) + (Ar x number of the other atom(s) if there are any)

e.g. Mr of HCL is (1 x 1) + (1 x 35.5) = 36.5

       Mr of H2O2 is (2 x 1) + (2 x 16) = 34 

1.15 deduce the number of outer electrons in a main group element from its position in the Periodic Table

The group in which the element is in on the periodic table shows how many electrons it has got in its outer most shell

e.g. Magnesium (Mg) is in group II and hence has 2 electrons in its outer most shell

1.14 deduce the electronic configurations of the first 20 elements from their positions in the Periodic Table

The first shell always has 2 electrons, and then on the shells can contain a maximum of 8 electrons.

In the periodic table, the row that an element is in corresponds to the amount of shells it has etc. row 3 has three orbiting shells.

Also the group that the element is in corresponds to the amount of electrons in its outer shells etc. group 3 has three electrons in its outer most shell.

An example:

Sulfur is in Group 6 Row 3 and hence it has two shells and six electrons in its outer most shell, making its electronic configuration 2.8.6

1.13 understand that the Periodic Table is an arrangement of elements in order of atomic number

As shown in the periodic table below, the atoms are arranged so that they are in increasing atomic mass. e.g. Hydrogen (1) → Helium (2) → Lithium (3) etc.

1.12 calculate the relative atomic mass of an element from the relative abundances of its isotopes

Relative atomic mass of an atom is the average of all the weights of its different isotopes.

It is measured using this formula:

(% of isotope 1 x its mass) + (% of isotope 2 x its mass) + (% of isotope 3 x its mass) etc. ÷ 100

e.g. Hydrogen has 3 isotopes: Protium, Deuterium and Tritium

                        Percentage                         RAM

Protium =         99.98%                                1

Deuterium =     0.018%                                2

Tritium =          0.002%                                3

(99.98 x 1) + (0.018 x 2) +  (0.002 x 3) = 0.99842 ≈ 1

1.11 understand the terms atomic number, mass number, isotopes and relative atomic mass (Ar)

Atomic Number:

Number of protons

Mass Number:

Number of protons + number of neutrons

Isotopes:

Isotopes are atoms with the same number of protons and electrons, however, they have a different number of neutrons. As shown in the diagram, the only difference between the isotopes is that there is a different amount of neutrons.

Relative Atomic Mass (Ar):

The mass of one atom is far too small to write out, so they are weighed in relativity to one hydrogen atom. e.g. an atom of Nitrogen (Ar of 14) is 14 times heavier than an atom of Hydrogen (Ar of 1)

1.10 recall the relative mass and relative charge of a proton, neutron and electron

Relative Charge:

Proton: +1

Neutron: 0

Electron: -1

Relative Mass:

Proton: 1

Neutron: 1

Electron: 1/1836 or 1/2000

1.9 understand that atoms consist of a central nucleus, composed of protons and neutrons, surrounded by electrons, orbiting in shells

The nucleus composes of protons and neutrons. While the orbiting shells around the nucleus contain electrons. Since electrons are ve- and the nucleus' overall charge is ve+ they attract each other, and that is what keeps an atom together.

1.8 explain how information from chromatograms can be used to identify the composition of a mixture.

The main way is through a chromatogram. The chromatogram is compared to a chromatogram of known substances. Where there are substances at the same height (assuming the same solvent has been used) they are the same substance.

1.7 describe experimental techniques for the separation of mixtures, including simple distillation, fractional distillation, filtration, crystallisation and paper chromatography

Simple Distillation:

The separation of a dissolved solid from a liquid. This is done by evaporating the liquid and the solid will remain.

Fractional Distillation:

The separation of a mixture of gases and/or liquids. This is done using a fractional column. The mixture is heated until everything is in the gaseous state. The gases then rise up the column where the temperature constantly decreases; as the gases have different boiling points, they will condense at different heights in the tube and are then collected.

e.g. mixture of hydrocarbons in crude oil are separated:

Filtration:

Usually used to separate liquids from non-dissolved solids. Filtration is where there is a barrier preventing the non-dissolved solids from passing while the liquid can.

e.g. a mixture of sand and water through filter paper. The sand gets caught in the filter paper while the water passes through.

Crystallisation:

A solution is heated allowing some of the solvent to evaporate. The solution is then left to cool; during this time crystals will begins to form.

Paper Chromatography:

Usually used to separate the different types of ink. Using a pencil (as it doesn't dissolve) draw a base line on the chromatography paper. Then draw a dot using the ink you want to separate. The chromatography paper is then placed in a solvent. The solvent will climb up the paper carrying with it the ink. The different types of ink will stop at different heights on the paper due to their different sizes.

1.6 understand the differences between elements, compounds and mixtures

Elements:

Elements are atoms which all contain the same amount of protons

Compounds:

Compounds are where two or more different types of elements are bonded together

Mixtures:

Mixtures are where two or more different types of elements are physically mixed, however not bonded.

1.5 understand the terms atom and molecule

Atom:

An atom is made up of a nucleus and orbital shells. The nucleus contains protons and neutrons while the orbital shells contain electrons.

Molecule:

A molecule is two or more atoms bonded together.

1.4 describe and explain experiments to investigate the small size of particles and their movement including: i dilution of coloured solutions ii diffusion experiments

Key definitions:

Dilution is the effect of placing a substance into a solvent and decreasing its concentration, e.g. adding 10cm³ of water to 10cm³ of 1 mol/dm³ hydrochloric acid, will turn the acid's concentration to 0.5 mol/dm³

Diffusion is the movement of particles from an area of high concentration to an area of low concentration. This only occurs in a fluid (gas or liquid)

Experiment 1 (dilution):

Take a beaker with 10cm³ of water containing any colour of food colouring. Then add another 10cm³ of non-coloured water to the beaker. The coloured water will dilute and hence the colour of the water will become lighter.

Experiment 2 (diffusion):

A piece of cotton soaked with HCL is placed at one end of a tube while another piece of cotton is soaked with ammonia (NH3) and is placed on the other side of the tube. The tube is then sealed. You will observe a white ring (ammonium chloride) form near the end of the cotton soaked in HCL. This is because the NH3 molecules have a relative atomic mass of 17 while the molecules of HCL have a relative atomic mass of 36.5; i.e. the molecules of ammonia are lighter than those of HCL.

1.3 explain the changes in arrangement, movement and energy of particles during these interconversions

Solid: Little energy, particles vibrating on spot, all particles are touching

                                           ↓ Add heat / Remove heat ↑

Liquid: More energy, particles move to fit container, particles all touching

                                           ↓ Add heat / Remove heat ↑

Gas: Lots of energy, particles fill entire container, particles aren't touching

1.2 understand how the interconversions of solids, liquids and gases are achieved and recall the names used for these interconversions

• Solid to Liquid = Melting

• Liquid to Solid = Freezing

• Liquid to Gas =Evaporation

• Solid to Gas = Sublimation

1.1 understand the arrangement, movement and energy of the particles in each of the three states of matter: solid, liquid and gas

Solid:
 As shown in the diagram, the particles in the solid are vibrating on a fixed spot. They have the least energy in comparison to the liquids and gases. Solids are held together by strong inter-molecular forces of attraction and are all touching each other

Liquid:

As with solids, all the particles in a liquid are touching each other. However, they can flow and will take the shape of their container. The inter-molecular forces of attraction are weaker than in a solid. The particles in a liquid have more energy than the molecules in a solid.

Gas:

Gas' have no inter-molecular forces of attraction meaning they aren't touching and will fill up the entire container. They have the most energy and can be compressed while solids and liquids can't.