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Please feel free to comment on sections or message us with any additional information or questions or if you would like a diagram added or something else.

Based off the course outline but please let us know if there's a topic that has been missed or needs beefing up

thanks :) – Eashal and Holly

Still doing:
- bonding (have notes on)
- chemical reactions

enthalpy

moles (see section)

- fossil fuels (don't know what notes to do for this)
- aqueous solutions and acidity (have notes on)

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Scientist's contribution to the discovery of the atom

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Scientist's contribution to the discovery of the atom

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Dalton
- proposed atomic theory
- everything is composed of extremely small particles called atoms
- all atoms of a given element are identical having the same size, mass and chemical properties
- law of conservation
J.J. Thompson
- plum pudding model
- demonstrated that cathode rays were streams of negatively charged particles
- discovered electrons
Rutherford
- planetary model
- dense, positive nucleus and orbiting electrons
- gold foil experiment
- if plum pudding model was correct then particles would pass through with little to no deflection
Chadwick
- identified neutrons after;
- Geiger and Marsden concluded that protons accounted for half the weight of the nucleus, so, there must be neutral particles present
- identified as product of alpha bombardment of Beryllium
Bohr
- previous model did not explain emission/absorption spectra
- limitations of planetary model –> electrons loosing energy
- quantised electron shells

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Electronegativity
- ability of an atom to attract electrons
- group 18 is excluded (octet rule)
- increases across a period because core charge increases and number of shells occupied remains constant
- decreases down a group because the number of shells increases so more shielding and more distance between charges
Atomic radius
- regarded as distance from nucleus to outermost shell
- atoms do not have defined boundaries so it is not possible to measure radii directly
- increases down a group because more shells are occupied
- decreases across a period because core charge increases so valence electrons are held more strongly to atom
First ionisation energy
- energy required to remove a valence electron from an atom in a gaseous state
- decreases down a group because there is grater distance and shielding so electrons are held less strongly and thus less energy required to remove them
- increases across a period because number of shells remains constant and core charge increases so valence electrons are more strongly attracted to the nucleus
Successive ionisation energy
- 1st ionisation energy is smallest because it experiences the least attraction due to shielding and being in the valence shell
- gradual increases within a shell because the core charge is shared amongst less electrons (increasing electrostatic attraction) and number of shells remains the same and core charge doesn't actually increase
- big jump across a shell as core charge increases across shells as there is less shielding
Electrostatic attraction
- between opposite charges
- strength dependent on magnitude of particles involved and distance between them
Core charge/nuclear charge
- measure of the attractive force felt by valence electrons towards the nucleus
- helps to explain trends in the periodic table
- positive charge minus number of electron in inner shell/s

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Absorption and emission spectra
- each element has a unique emission/absorption spectra
- electrons absorb and release energy as they move between energy levels
- energy absorbed and released corresponds to a specific wavelength and frequency of a colour of light
- Bohr's model says that electrons can only exist  at certain discrete levels which accounts for this
- each line in emission/absorption spectra corresponds to specific electrons transition between two energy levels
Mass spectrometer
- isotopic abundances can be measured by mass spectrometry
- what it does:

separates individual isotopes in sample of element

determines mass of each isotope relative to carbon-12 standard

calculates relative abundance of the isotope in the sample

- how it works:

sample is vaporised (gas) and then ionised using high-energy electrons

ions are accelerated and separated according to their m/z ratio

ions that are a particular m/z are detected by a device that counts the number of ions that strike it

- mass spectra

number of peaks indicates number of isotopes

position on horizontal axis indicates Ar

relative heights of peaks corresponds to the relative abundance –> sometimes scale does not add up to 100% and will need to adjust

Flame Test
- based on ability of electrons to release and absorb energy as they move between energy levels
- inserting samples into a non-luminous bunsen burner flame
- can detect presence of only small number of metal elements
- depends on person's perception of colour
- cannot separate colours from different elements so mixtures like allows cannot be tested
AAS
- based on ability of electrons to release and absorb energy as they move between energy levels
- atomic absorption spectroscopy
- can detect large range of elements even in mixtures and with low concentration
- hollow cathode lamp as light source (matching target metal)
- flame atomises sample so metal atoms are free to absorb light
- wavelength filter selects desired wavelength/frequency of light and detector determine to what extent the sample has absorbed
- absorbance is proportional to concentration of target metal atoms

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From EC 2.10: Atomic absorption spectrometer schematic.
In this example of the AAS, a hollow cathode lamp is used as the light source. The metal of the cathode is chosen to match the target metal being analysed from the test solution. In this way the light it produces is of the precise wavelengths that can be absorbed by target metal atoms alone.
Th test sample is aspirated (sucked up) into the gas/air stream supplying the flame of the AAS. This suitably hot flame ensures the sample is decomposed and atomised. Any metal atoms originally present in the test sample are now present as free atoms in the flame. In this form the target metal atoms freely absorb light from the light beam directed through it.
A wavelength filter selects the desired wavelength of light from the exiting beam and the amplifier/signal detector determines the extent to which it has been absorbed, called the absorbance. Absorbance is proportional to the concentration of the target metal atoms present in the flame. It is used, along with a calibration curve, the determine the metals concentration in the test solution.

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Separation by particles
- sieving

passing through mesh

- filtration

separates solid particle from liquid or gas

pool filters and industrial chimneys

- gravitional filtration

filtration paper and funnel

- vacuum filtration

Büchner funnel

faster than gravitational as vacuum sucks mixture in so it occurs faster (see diagram

Separation by density
- sedimentation

denser particles settle at bottom of container

- decantation

process of pouring liquid off from the sediment

- centrifuge

spinning mixture rapidly speeds up separation process

denser particle are pushed to the outside of the container by centrifugal force

Separation by boiling point
- distillation

both liquids (components) are conserved – unlike evaporation

condensor

- fractional distillation

condensor

fractional column (w/ beads) allows increased contact between rising vapour and falling condensate

separates liquids that are mixed with only slightly different boiling points

more volatile component existing as a vapour at the top and less volatile condensing back

volatile means easily evaporated

- evaporation

solvent is boiled off to leave solute

solute is what dissolves in liquid

solvent is the liquid

Separation by electric charge
- electrostatic separation

opposite charges (like magnets)

can work with gases to separate solid particle from it

- chromatography

see intermolecular forces and gases

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Nanoscale
- refers to structures that are between 1 and nanometers (nm)
- one billionth of a metre (10^-9m)
Nanomaterials
- substances, natural and synthetic, that have at least one unit in the nanoscale
- fullerenes

three-dimensional structures formed by networks of carbon atoms

like carbon nanotube

nanotube are formed from flat two-dimensional layers of carbon atoms arranged like hexagons called graphene

Top-down fabrication
- starts with material of larger scale than desired and material is either selectively removed or size is progressively reduced by grinding
- Disadvantage- limited to relatively simple structures
- Advantage- large quantities can be produced relatively cheap and product demonstrates good level of uniformity
Bottom-up fabrication
- Individually selected atoms or molecules are successively built up until the required shape and size of material is formed
- Advantage- can be used for more complicated structures due to ability to manipulate individual atoms or molecules on nanoscale

- Disadvantage- do not scale up to commercial levels efficiently so only economical for research
Nanoparticles
- usually spherical particles with 1-100nm diameter
in nanoscale range, properties of materials begin to change from bulk materials (due to surface area)
- zinc oxide in sunscreen is white when applied to skin but zinc nanoparticles interact with light differently and appear clear
Diamond
- allotrope of carbon
- each carbon atom bonded to 4 neighbouring atoms
- 3d tetrahedron
- bond angle = 109.5°
- hard and brittle, high mp and bp

strong covalent bonding so large amounts of energy needed to break apart

- non-conductors of electricity

no free moving electrons

Graphite
- carbon allotrope
- each carbon bonded to 3 neighbouring atoms
- form flat 2D sheets (graphene)  of interlocking hexagonal rings
- bond angle = 120°
- graphite is layers of graphene stacked with weak dispersion forces
- delocalised electrons move between layers and are not involved in bonding
- soft and weak

weak dispersion forces between layers can be easily broken

- high mp and bp

bonds within graphene layers are strong covalent bonds

- conduct electricity

delocalised electrons

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Types of fuels?

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Law of conservation of matter
- in a chemical reaction, matter is neither created nor destroyed, only rearranged
- conserved –> same w/energy
- know definition of system and surroundings because energy can be released from system to the surroundings
Chemical energy
- attraction between electrons and protons in atoms
repulsion between nuclei (protons–positive charge)
- repulsion between electrons
- vibrations and rotations around bonds
Endothermic
- total chemical energy of the products is greater than the total energy of the reactants, energy is absorbed from the surroundings
Exothermic
- total chemical energy of the products is less than the total energy of the reactants, energy is released into the surroundings
Enthalpy

-

Moles
- convenient quantity for counting particles
- amount of a substance
- Avogadro

one mole is defined as the amount of a substance that contains the same number of specific particle as there are atoms of C-12 in 12g

6.022*1023 mol-1

n = N/NA

n is number of moles and N is number of particle in substance

- molar mass

mass (g) of 1 mol of a particular element

g/mol

C-12 has a molar mass of 12g/mol exactly

C has molar mass of 12.01g/mol because isotopes

- different things for moles like relative and formula mass and 🤬 help......

Stoichiometry
- n(unknown) = coefficient(unknown)/coefficient (known) * n(known)
- why? because ratio
Percentage composition
- percentage composition of a given compound tells you the proportion by mass, of different elements in the compound
- mass of element in 1 mol of the compound/molar mass of the compound * 100

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Saturation
Solubility
Arrhenius model
Acid and base reactions
Acid rain

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Collision theory + rate of reaction
- states that for a reaction to occur, particles must collide with the correct orientation and with sufficient energy, equal to or greater than the activation energy, for a chemical reaction to occur.
- when explaining collision theory refer to rate of reaction and how the frequency of collisions and number of successful collisions are affected by changing factors
- rate of reaction is defined as the change in concentration of a reactant or product per unit time
Temperature
- higher temperature means the more rapidly a reaction occurs
- particles have more kinetic energy which means increased frequency of collisions and increased energy of particles so increased number of successful collisions
Surface area
- smaller particles have larger surface area than the same mass of large particles
- small particles react much faster
- smaller particles also means higher frequency of collisions as more particles (compared to large particles of same mass)
Concentration
- higher concentrations usually lead to increased reaction rates because there is a higher concentration of reactant particles –> so increased frequency of collisions
Gas pressure
- increasing pressure on a reaction increases the rate at which the reaction takes place
increasing the pressure at constant temperature will result in the reactant particles becoming closer together and thus increases the chance and frequency of collisions
Catalysts
- catalysts allow the reaction to follow a more energetically favourable pathway
- catalysts lower the activation energy by providing an alternative reaction pathway for the reaction and thus increase the number of successful collisions (as energy required is less)
- homogenous catalysts are in the same physical state as the reactants and products of the reaction
- heterogenous catalysts are in a different physical state from the reactants and products of the reaction
- catalysis is the increase in the rate of a chemical reaction due to the presence of a catalyst
- adsorption is the attraction and binding of molecules or particles of one substance to the surface of another (same as chromatography)
How can you measure the rate of a reaction
- measure following during specific time intervals:

mass loss

volume of gas produced

colour change

concentration changes

pH change

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Shapes and Polarity

- Valence shell electron pair repulsion theory (VSEPR)

electron pairs in a molecule will repel each other so they are as far apart as possible

- Shapes

pyramidal, bent/V-shaped, linear shape, trigonal planar

- Polarity

When there is a large difference between electronegativity, there is greater polarity

Dipoles: occurs when there is a separation of positive and negative charges

- Non polar molecules

Symmetrical so dipoles cancel outs

if a molecule is symmetrical but has lone electron pair then it is polar

- Polar molecules

Asymmetrical so dipoles don’t cancel out

Types of Intermolecular Forces

- Dipole-dipole forces

Only in polar molecules

The partially positive end of a polar molecule is attracted to the partially negative end of another molecule

Higher the dipole-dipole forces, higher the melting & boiling points

- Hydrogen bonding

A form of dipole-dipole force

Occurs when Hydrogen is bonded to the lone pairs on an oxygen, nitrogen or fluorine atom

- Dispersion forces

Can occur between non polar and polar molecules

These forces are caused by temporary dipoles caused by random movement of electrons

Electrons occasionally gather at one end thus forming temporary dipoles which induce dipoles in neighbouring molecules

Chromatography

- Adsorption

how well a component of the mixture sticks to the stationary phase

depends on polarity

the attraction and binding of molecules or particles of one substance to the surface of another

- Solubility

how well a component of the mixture dissolves in the mobile phase

- Retention factor

distance component travelled from origin ÷ distanced solvent front travelled from origin

Gases

-volume of the particles in a gas is very small compared with the distance between particles

-average kinetic energy proportional to temperature

-particles are in rapid, random motion colliding with each other and containment wall

-forces between particles in a gas is negligible

-low density, easily compressed

Pressure

- Force exerted by a gas due to collisions of gas particles against walls of container
equation

PV=nRT

P= pressure in kPa

V= volume in L

n= total number of moles of gas present

R= 8.31 J K mol or 0.082 atm K mol

T=temp in K

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Hydrocarbons
- compounds containing only carbon and hydrogen atoms
- fossil fuels, such as coal, oil and natural gas, come from the remains of plants and animals (are hydrocarbons)
- crude oil is source of many hydrocarbons

crude oil has low density so it can migrate upwards through crust

hydrocarbons are only separated by fractional distillation

components undergo process called fracking which breaks down larger molecules into smaller ones using heat and catalyst

meth- 1
eth-2
prop-3
but-4
pent-5
hex-6
hept7-
oct-8
non-9
dec-10

Alkanes
- hydrocarbon that contains only single bonds
- methane is simplest hydrocarbon (and alkane)
- a series of molecules in which each member differs by CH2 from the previous member – a homologous series

compounds that are members of the same homologous series have similar structure, a pattern to their physical properties, similar chemical properties, same general formula

- end is -ane
- same general formula of CnH2n+2
- weak forces between molecules because they are non-polar
- naming

1. identify the longest unbranched carbon chain and count the number of carbon atoms in that chain. this gives the molecule it's stem name

2. if there are branches to be added to the name, number the carbon atoms in the chain from the end of the chain that will give the smallest numbers to branching groups

3. Identify the type and number of the alkyl groups attached to the chain

4. Place the number and position of each alkyl groups at the beginning of the compound's name .

5. If two identical side chains are present, use 'di-' as a prefix; for three use 'tri-'

6. If there are different alkyl side chains, list them in alphabetical order at the start of the name, with their numbers to indicate their respective positions

7. Carefully check that you have identified the longest unbranched carbon chain. Sometimes the longest carbon chain is not drawn in a straight line

Alkenes
- homologous series of hydrocarbons with at least one carbon-carbon double bond
- simplest alkene is ethene then propene
- end is -ene
- same general formula of CnH2n
- Cis-trans (geometric) isomers of alkenes

placement of hydrogens around double bond

trans is diagonal

cis is same side

- naming

1. identify the longest unbranched carbon chain. the chain must include the double bond

2. number the carbon atoms in the chain from the end of the chain that will give the smallest number to the double-bonded carbon atoms

3. name the alkyl groups after the alkane from which they are derived

4. Identify the position of the double bond by the number of the first carbon atom involved in the bond. Use the suffix '-ene' to indicate the presence of a double bond, e.g. hex-2-ene.

5. List the number and position of each of the alkyl groups at the beginning of the compounds name in alphabetical order

6. If two identical side chains are present, use di- as a prefix; for three use tri-

7. Identify whether the structure exhibits geometric isomerism and if so, whether it is a cis or trans isomer

Benzene

- Benzene has the formula C6H6
- consists of a six-sided carbon ring, with six delocalised electrons contained within the ring
- all c-c bonds are the same length
- alternate between double and single c-c bond (for the model we're learning this year)

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Metallic
- metal ions in 3D lattice
- delocalised electrons and fixed cations
- metallic strength

greater number of e- released to sea = stronger attraction

greater charge = stronger attraction

smaller cation size = stronger attraction

Properties of metals
- high densities and tensile strength

strong electrostatic forces of attraction between cations & electrons

- high melting point and boiling point

large energy needed to overcome electrostatic forces of attraction between particles

- good conductors of heat

free to move electrons transmit heat energy as they vibrate and transfer heat energy to other electrons and cations rapidly

- good conductors of electricity

free to move electrons move towards positive electrode in electric circuit and carry charge (thus conduct electricity)

- malleable and ductile

when forces cause ions to move past each other, ion layers still held together by delocalised electrons

- lustrous

electrons reflect light of all wavelengths and appear shiny whilst moving

Reactivity series
- reactivity is determined by attraction of valence electrons to the nucleus
K
Na
Ca
Mg
Al
Zn
Fe
Pb
Cu
Ag
Au
Pt

Ionic
- metals and non-metals (except ammonium)
- form 3D lattice (crystal)
- strong electrostatic attraction between ions
- ions occupy fixed positions
- non-directional forces
Properties of ionic substances
- solids at room temperature w/ high melting point and boiling point

the electrostatic attraction between cations and anions is strong therefore greater energy required to break bonds

- hard but brittle

when strong force applied to lattice, the ion layers move relative to each other

like ions end up aligned next to one another

results in repulsion and cause crystal lattice to shatter apart

- non-conductors of electricity in solid state

solid form ions have fixed positions (are not free to move and carry charge–conduct electricity)

- conducts electricity in liquid and aqueous state

in water ionic bonds are broken and the ions move freely

when current applied cations move towards negative electrode and anions towards the positive

ions are free to move and so can conduct

- different solubilities in water

when soluble, ionic compounds added to water, ions break away from ionic lattice and mix with water molecules (dissociation)

when insoluble, ionic compounds are added and the ions remain bonded

solubility depends on attraction between cations and anions, and, water molecules and ions

Covalent
- non-metals
- share valence electrons
- directional bonding
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cis-trans (geometric) isomers of alkenes

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cis-trans (geometric) isomers of alkenes

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A. is cis
B. is trans
C and D are classified as neither because they are both