Preliminary stuff:

Equations:

c=fλ
E=hf
n=m/M

n=CV
PV=nRT
(P1V1)/T1=(P2V2)/T2

Q=mcΔT
% atom economy=(molar mass of desired product)/(molar mass of all reactants)×100

ΔH⦵=Σ(ΔHf⦵products)−Σ(ΔHf⦵reactants)

ΔH⦵=Σ(ΔHc⦵reactants)−Σ(ΔHc⦵products)

ΔG⦵=ΔH⦵−TΔS⦵
ΔG=ΔG⦵+RTlnQ
ΔG⦵=−RTlnK
ΔG⦵=−nFE⦵
k=Ae^(−Ea/RT)

lnk=(−Ea)/(RT)+lnA

pH=−log10[H3O+] or pH=−log10[H+]

Kw=[H+][OH–]
pOH=−log10[OH–]

Physical constants:

e: Elementary charge. 1.602177×10^−19 C

me: Electron rest mass: 9.109384×10^−31 kg

mp: Proton rest mass. 1.672622×10^−27 kg

mn: Neutron rest mass. 1.674927×10−27 kg
c: Speed of light in a vacuum. 3.00×108 ms^−1
h: Planck constant. 6.63×10^−34 J s
NA: Avogadro’s constant. 6.02×10^23 mol−1
R: Gas constant. 8.31 J K^−1 mol^−1
VM: Molar volume of an ideal gas at STP. 2.27×10^−2 m^3 mol^−1=22.7 dm^3 mol^−1

cW: Specific heat capacity of water. 4.18 kJ kg^−1 K^−1=4.18 J g^−1 K^−1
KW: Ionic product constant for water at 298.15 K. 1.00×10^−14 mol^2 dm^−6
F: Faraday constant. 9.65×104 C mol^−1

Metric (SI) multipliers:

Unit conversions:

Temperature (K) = temperature (°C) + 273.15

1 dm^3 = 1 litre = 1 × 10^−3 m3 = 1 × 10^3 cm3

STP conditions: 273.15 K and 100 kPa

SATP conditions: 298.15 K and 100 kPa

Electromagnetic spectrum:

Elements, compounds, and mixtures:

Vocabulary:

Pure substances: made up of one type of substance and have a fixed composition.

Mixtures: made by combining two or more pure substances together, so they do not have a fixed composition

Elements: The building blocks of matter. Simplest forms of matter and consist of only one type of atom.

Allotropes: different forms of an element in the same physical state.

Compounds: Composed of two or more different elements chemically combined in fixed ratios.

Homogeneous mixtures: Do not have visible phases or boundaries, and they have a uniform composition, making the composition the same throughout the mixture.

Heterogeneous mixtures: Has visible phases or boundaries and is non-uniform, meaning that different parts of the mixture have a different composition.

Notes:

Mixtures:

• One or more elements or compounds in no fixed ratio.

• Contain pure substances that are not chemically bonded so they can be separated by physical means.

• Components of this retain their individual properties.

Homogenous mixture:

• Can be considered homogenous when all substances are in the same state and the same amount.

Separation techniques:

Vocabulary:

Filtration: The separation of an insoluble solid from a liquid or solution

Filtrate: A substance that has passed through a filter.

Residue: The insoluble component, usually a solid, of a mixture that remains after filtration.

Solvation: The process where the solvent particles surround and interact with the particles of the solute.

Solubility: The ability of a substance to dissolve into a solvent to form a solution.

Evaporation: Used to separate a mixture which has a solute dissolved in a solvent which is usually water.

Distillation: The separation of a liquid mixture based on the difference in volatility or boiling points between the components of the mixture

Volatility: The tendency of a substance to undergo evaporation.

Miscible: Capable of being mixed in any ratio without separation.

Paper chromatography: Used to separate a mixture of solutes in a solvent.

Recrystallisation: Used to remove impurities that are mixed in with a solid.

Residue: The insoluble component, usually a solid, of a mixture that remains after filtration.

Condenser: A piece of laboratory glassware used to condense a gas into a liquid using cold water.

Chromatogram: The output from chromatography. In liquid chromatography this is the paper containing the separating mixture.

Synthetic: A substance which is artificially made or produced, usually through chemical reactions in a laboratory or factory.

Dyes: Synthetically made and are typically small, polar molecules. Will dissolve in a polar solvent such as water and produce a transparent solution.

Pigments: Naturally derived from plants and are typically large, non-polar molecules. When mixed with a solvent will remain suspended and create an opaque solution.

Solvent front: The distance from the pencil line to where the solvent (the mobile phase) reached on the chromatography paper at the time it was removed from the solvent.

Notes:

Solvation:

• Can separate a heterogenous mixture of solids through differing solubility

• When one substance is soluble and the other isn’t, the insoluble solid can be separated with filtration.

Distillation:

• Each liquid has a different boiling point.

• One evaporates first and rise up the distillation column through the condenser.

Paper chromatography:

• The mixture is first dissolved in a solvent. Known as the mobile phase

• A piece of chromatography paper is then placed in the solution. Known as the stationary phase.

• Components of the mixture move through the stationary phase at different rates due to differences in solvation

Recrystallisation:

• The impure mixture is first dissolved in a small volume of hot solvent. Any insoluble impurities can be filtered off.

• The solution is then cooled which causes the solubility of the dissolved solids to decrease.

• The desired product forms crystals leaving the soluble impurities in the solution

• Impurities are then filtered to obtain the pure product.

States of matter and changes of states:

Vocabulary:

Kinetic energy:

Density: Mass per unit volume

Heat energy: A form of energy that is transferred between objects of different temperatures.

Physical change: A reversible change that does not change the chemical properties of a substance.

Sublimation: The change of state from a solid to a gas with no liquid state.

Deposition: The change of state from gas to solid with no liquid state.

Vaporisation: The change of state from a liquid to a vapour (or gas).

Evaporation: a change of state from liquid to gas and takes place only at the surface of the liquid. Can occur at temperatures below the boiling point of the liquid.

Boiling: occurs at a specific temperature and is a change of state from liquid to gas throughout the liquid. Bubbles of gas are formed within the liquid, not only at the surface.

Notes:

Kinetic molecular theory:

• All matter is made up of small particles

• Particles all have kinetic energy

• The amount of kinetic energy is proportional to temperature

• Collisions between particles are elastic, meaning no energy is lost.

Solid:

• Cannot be compressed because molecules are already packed

• Fixed shape and fixed volume due to strong forces of attraction

• Solids cannot flow.

Liquid:

• There are weaker forces of attraction.

• Do not have a fixed shape and usually take the shape of the bottom of its container

• Still cannot be compressed

Gas:

• Do not have a fixed shape or volume

• Takes the same shape as the container

• Volume depends on the temperature and the pressure of the gas itself

• Very weak attraction

• Can be compressed

Temperature and kinetic energy:

Formula:

Ek: 1/2mv^2

Vocabulary:

Celcius: Based on the freezing point of water (0 °C) and the boiling point of water (100 °C).

Kelvin: An absolute temperature scale where the lowest possible value is 0 K, known as absolute zero.

Absolute zero: 0 K. Particles have zero kinetic energy.

Heating curve: Shows how the state of matter changes as heat is added. Opposite is cooling curve

Intermolecular force: Attractive (or repulsive) forces that exist between the molecules of a substance.

Notes:

Celcius and Kelvin:

• To get Kelvin from Celcius, add 273, and vice versa.

Heating:

• The temperature remains constant during change of state because all the added/removed heat is being used to overcome the intermolecular forces that act between the particles.

• The relationship between the temperature in Kelvin and the kinetic energy of the particles is directly proportional.

Atomic structure:

Vocabulary:

Nucleus: The region at the centre of the atom where the protons and neutrons are located.

Electrons: The subatomic particles with a relative mass of 1/2000 and a charge of −1.

Protons: The subatomic particle with a relative mass of 1 and a charge of +1.

Neutrons: The subatomic particle with a relative mass of 1 and no charge.

Nucleons: A collective term for protons and neutrons.

Atomic number: The number of protons in the nucleus of an atom. Symbol Z.

Mass number: Also known as the nucleon number. The number of protons and neutrons in the nucleus of an atom. Symbol A.

Ions: A charged particle. It has a charge as the number of protons do not equal the number of electrons.

Notes:

Isotopes:

Vocabulary:

Isotopes: atoms of the same element that have different numbers of neutrons.

Relative atomic mass: Atoms of the same element that have different numbers of neutrons.

Percent abundance: The percent of an isotope in a naturally occurring sample of an element

Notes:

Isotopes:

• Different physical properties due to mass (boiling point, melting point, density)

Mass spectra of elements:

Vocabulary:

Mass spectrometer: An analytical device used to determine the m/z ratio of the isotopes in a naturally occurring sample of an element.

m/z ratio: The ratio of the mass of an ion divided by its charge.

Molecular ions: A positively charged ion produced in a mass spectrometer.

Relative intensity: The size of a peak in a mass spectrum relative to the most abundant ion which is shown as the tallest peak in the spectrum.

Base peak: In mass spectrometry, the peak associated to the most abundant ion. It is used to calculate the relative intensity of other ions.

Notes:

Mass spectrometry:

• Vaporisation: The substance is vaporised to produce gaseous molecules.

• Ionisation: High-energy electrons are fired at the said gaseous molecules, which causes them to be ionised, forming gaseous ions.

• Acceleration: The gaseous ions are accelerated in an electric field.

• Deflection: The gaseous ions are deflected by an electromagnet. The degree of deflection they undergo depends on their m/z ratio. Ions with lower m/z ratios are deflected the most and ions with higher m/z ratios are deflected the least.

• Detection: the gaseous ions are detected and a mass spectrum is produced.

Mass spectrum graph:

Line spectra:

Vocabulary:

Electromagnetic spectrum: The range of frequencies or wavelengths of electromagnetic radiation.

Visible light: The segment of the electromagnetic spectrum that the human eye can see, typically between 380 to 700 nanometers.

White light: Light that is composed of all the frequencies or wavelengths of visible light.

Spectroscopy: The study of the interaction between electromagnetic radiation and matter.

Emission spectra: The range of frequencies or wavelengths of electromagnetic radiation emitted during an electron transition from a higher to a lower energy level.

Electron transitions: The movement of an electron between the energy levels in an atom, accompanied by the absorption or emission of energy

Frequency v: The number of complete waves passing a point each second. This is measured in hertz (Hz).

Wavelength λ,: The distance from a point on one wave to the equivalent point on the adjacent wave. This is measured in metres (m).

Oscillate: Move or swing back and forth at a regular speed.

Spectroscope: A device for viewing the emission spectra of elements in the visible region.

Emission line spectrum: The range of frequencies or wavelengths of electromagnetic radiation emitted during an electron transition from a higher to a lower energy level.

Bohr model of the atom: An atomic model that shows energy levels at fixed distances from the nucleus.

Principal quantum number: The main energy levels occupied by electrons, assigned the letter n.

Ground state: The lowest energy state of an atom when all its electrons occupy their lowest energy levels.

Photons: An elementary particle of discrete amounts of electromagnetic radiation.

Excited state: A higher energy state than the ground state when electron(s) gain energy and move to higher energy levels.

Notes:

Electromagnetic spectrum:

• All regions of the electromagnetic travel at the speed of light - 3*10^8 m/s

Continuous spectrum:

• All wavelengths and frequencies of visible from red to violet.

• 
  

Emission line spectrum:

• Only shows specific wavelengths or frequencies of light

• Shown as coloured lines on a black background.

• Converge at higher energies due to higher frequnecy and shorter wavelength, v.v.

• 

Bohr model of the atom:

• Electrons orbit the nucelus

• Electrons can only exist in certain shells, not in between.

• Electrons could move between levels by emitting/absorbing energy.

• Converge at higher energy levels

Electron transition:

• If an electron absorb a discrete amount of energy, it will transition from a lower to a higher energy level

• The unstable electron emits the same amount of energy and transitions back

• Transitioning through more levels require/generate more energy, which is indicated by the colour.

Hydrogen emission spectrum:

• From higher energy levels to n = 1 emit energy corresponds to UV radiation. Highest energy transitions.

• From higher energy levels to n = 2 emit energy corresponds to visible light.

• From higher energy levels to n = 3 emit energy corresponds to infrared radiation. Lowest energy transitions.

Main energy levels and sub-levels:

Vocabulary:

Heisenberg uncertainty principle: A scientific principle that states we cannot know both exact location and velocity of an electron at the same time.

Sub-levels: The smaller division of the main energy levels, assigned the letters s, p, d or f.

Notes:

Main and sub levels:

Electron configuration:

Vocabulary:

Electron configuration: Electronic configuration shows the arrangement of electrons in their different levels around the nucleus of an atom.

Aufbau principle: A scientific principle that states that electrons fill the atomic orbital of the lowest energy levels first.

Pauli exclusion principle: An atomic orbital can only hold two electrons and they must have opposite spins.

Hund’s rule: when we have degenerate orbitals then each orbital is filled with a single electron before being doubly occupied.

Degenerate orbitals: Atomic orbitals that have equal energy levels. For example, the three 3p orbitals are degenerate orbitals.

D-block elements: Elements located in groups 3–12 of the periodic table which have their valence electrons in the d-orbitals.

Orbital diagrams (Arrow-in-box diagrams): Diagrams that represent how electrons occupy the atomic orbitals of an atom. Drawn as square boxes with headed arrows to show spin directions.

Notes:

Sub-levels order:

Condensed electron configuration:

• Write full configuration

• Write the symbol of the previous noble gas.

• Write for each sub-level (s, p, d, f) their largest variant.

• E.g. Carbon = 1s^2, 2s^2, 2p^2 = He 2s^2. 2p^2
  

Exceptions of Aufbau principle:

• Cr (Chromium) = Ar 4s^1, 3d^5

• Cu (Copper) = Ar 4s^2, 3d^10
  
  

Orbital diagrams:

• Only two arrows in one box.

• Must have opposite spins

• Must form all singles first before forming doubles

Calculating ionisation energies:

Formula:

E = hf

• E: energy. Joules (J)

• h: Planck’s constant, 6.63*10^-34. Joule seconds (J s)

• f: frequency: seconds (s^-1)

c = λf:

• c: Speed of light, 3.00*10^8. Meters per second (m/s)

• λ: wavelength. Meters (m)

Vocabulary:

Strong nuclear force: The force that attracts subatomic particles, such as protons and neutrons, toward each other.

Ionisation energy: The energy required with remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous 1+ ions.

Convergence line: The point at which the spectral lines converge. Can be used to calculate the ionisation energy.

Avogadro’s number: The number of particles in one mole of substance. Equal to 6.02 × 1023

Notes:

Ionisation:

• Removing an electron in its ground state. E.g. Hydrogen, from n=1 to n=∞

• The energy required is dependent on the nuclear charge (# of protons) and the distance between the nucleus and the outer electrons.

Trends in ionisation:

Beryllium and Boron:

• Beryllium has the electron configuration 1s^2 2s^2

• Boron has the electron configuration 1s^2 2s^2 2p^1

• Electrons of the p-energy levels are further from the nucleus than s-energy levels and thus are easier to remove.

• The same goes of Magnesium (Mg) and Aluminium (Al)
  

Nitrogen (N) and Oxygen (O):

• Nitrogen has the electron configuration 1s^2 2s^2 2p^3

• Oxygen has the electron configuration 1s^2 2s^2 2p^4

• The first doubly occupied electron is repulsed by the second doubly occupied electron and requries less energy to remove.

Successive ionisation energies:

Vocabulary:

Successive ionisation energies: The energies required to remove more and more electrons from an ion that is becoming increasing positive.

Notes:

Successive ionisation energies:

• Progressively need more energy because the ion is becoming increasinly more positive.

• This leads to an increase in the electrostatic attraction between the nucleus and the remaining electrons.

• There is a sharp increase in energy whenever it switches to a different energy level, which can be used to determine the number of valence electrons.

The mole and Avogadro’s constant:

Formula:

Molar mass: n = m/M

• n is “moles”

• m is “mass”

• M is “molar mass”

Vocabulary:

Mole: The number of particles present in exactly 12 g of the carbon-12 isotope. This is equal to the Avagadro constant: 6.02 × 1023 particles.

Elementary entities: Any chemical particle such as atoms, molecules, ions or electrons.

Formula unit: The empirical formula for an ionic compound that represents the simplest ratio of ions making up the compound.

Relative atomic mass: The weighted average mass of an atom compared to 1/12 the mass of an atom of carbon-12.

Relative formula mass: The mass of a compound relative to 1/12 the mass of an atom of carbon-12. Does not have any units.

Molar mass: The mass of one mole of a substance, expressed in units of g mol-1.

Empirical formula:

Law of Definite Proportions: For any given compound, the ratio of constituent elements is fixed. Also known as law of definite composition or Proust's law.

Empirical formula: a chemical formula showing the simplest ratio of elements in a compound rather than the total number of atoms in the molecule.

Molar concentration:

Formulas:

One litre (L) = One cubic decimeter (dm³)

Concentration: C = m/V

• C: Concentration (g/dm³)

• m: Mass of solute (g)

• V: Total volume of solution (dm³)

Molarity: M = mol/V

• M: Molarity

• mol: Moles of solute

• V: Total volume of solution (dm³)

Vocabulary:

Concentration: The number of particles or moles in a given volume, mol dm-3.

Mass balance: Laboratory apparatus used to accurately measure the mass of a substance.

Volumetric flash: A piece of laboratory glassware used to prepare a standard solution with a precise volume.

Notes:

[]:

• Square brackets [] is often used to express molar concentration:

• e.g, [NaCl] = 1.00 mol/dm³

Preparing a standard solution:

Avogadro’s law of combining volumes:

Vocabulary:

Pressure: A measure of the force which the particles in a container exert on the surface as the particles collide with it.

Avogadro’s Law: Equal volumes of gases at the same temperature and pressure will contain the same number of gas particles.

Notes:

Factors affecting gases:

• Volume of the container

• Temperature of the gas

• Pressure of the gas

Ideal gas:

Vocabulary:

Ideal gas: Gases that are assumed to consist of particles that have negligible volume and negligible attractive forces.

Real gas: nonideal gases whose molecules occupy space and have interactions. do not adhere to ideal gas law

Notes:

Ideal gas model:

• Particles are in constant, random, and straight-line motion.

• Negligible intermolecular forces

• Gas volume is negligible; distance between particles is greater than size of particles.

• Kinetic energy is directly proportional to absolute temperature (Kelvin).

• Any collisions made by particles are elastic, meaning that they just bounce off without losing energy.

• Requires high temperature and low pressure

Measurements

• Volume:

  • mL or cm³

  • L or dm³

• Temperature:

  • Kelvin (K)

• Pressure

  • How frequently particles hit the walls of the container

  • Pascals (Pa or kPa)