IBDP Chemistry Study Guide and Notes for SL/HL (2022-2023)

• Positive ions (cations) form by metals losing valence electrons.
• Negative ions (anions) form by non-metals gaining electrons.
• The number of electrons lost or gained is determined by the electron configuration of the atom.
• The ionic bond is due to electrostatic attraction between oppositely charged ions.
• Under normal conditions, ionic compounds are usually solids with lattice structures.

• The mole is a fixed number of particles and refers to the amount, n, of substance.
• Masses of atoms are compared on a scale relative to ¹²C and are expressed as relative atomic mass (A_r) and relative formula/molecular mass (M_r).
• Molar mass (M) has the units g mol^-1.
• The empirical formula and molecular formula of a compound give the simplest ratio and the actual number of atoms present in a molecule respectively.

• Reactants can be either limiting or excess.
• The experimental yield can be different from the theoretical yield.
• Avogadro’s law enables the mole ratio of reacting gases to be determined from volumes of the gases.
• The molar volume of an ideal gas is a constant at specified temperature and pressure.
• The molar concentration of a solution is determined by the amount of solute and the volume of solution.
• A standard solution is one of known concentration.

• Atoms contain a positively charged dense nucleus composed of protons and neutrons (nucleons).
• Negatively charged electrons occupy the space outside the nucleus.
• The mass spectrometer is used to determine the relative atomic mass of an element from its isotopic composition.

• Emission spectra are produced when photons are emitted from atoms as excited electrons return to a lower energy level.
• The line emission spectrum of hydrogen provides evidence for the existence of electrons in discrete energy levels, which converge at higher energies.
• The main energy level or shell is given an integer number, n, and can hold a maximum number of electrons, 2n².
• A more detailed model of the atom describes the division of the main energy level into s, p, d and f sub-levels of successively higher energies.
• Sub-levels contain a fixed number of orbitals, regions of space where there is a high probability of finding an electron.
• Each orbital has a defined energy state for a given electronic configuration and chemical environment and can hold two electrons of opposite spin.

• The periodic table is arranged into four blocks associated with the four sublevels— s, p, d, and f.
• The periodic table consists of groups (vertical columns) and periods (horizontal rows).
• The period number (n) is the outer energy level that is occupied by electrons.
• The number of the principal energy level and the number of the valence electrons in an atom can be deduced from its position on the periodic table.
• The periodic table shows the positions of metals, non-metals and metalloids. 

• Vertical and horizontal trends in the periodic table exist for atomic radius, ionic radius, ionization energy, electron affinity and electronegativity.
• Trends in metallic and non-metallic behavior are due to the trends above.
• Oxides change from basic through amphoteric to acidic across a period.“

• Positive ions (cations) form by metals losing valence electrons.
• Negative ions (anions) form by non-metals gaining electrons.
• The number of electrons lost or gained is determined by the electron configuration of the atom.
• The ionic bond is due to electrostatic attraction between oppositely charged ions.
• Under normal conditions, ionic compounds are usually solids with lattice structures.

• A covalent bond is formed by the electrostatic attraction between a shared pair of electrons and the positively charged nuclei.
• Single, double and triple covalent bonds involve one, two and three shared pairs of electrons respectively.
• Bond length decreases and bond strength increases as the number of shared electrons increases.
• Bond polarity results from the difference in electronegativities of the bonded atoms.

• Lewis (electron dot) structures show all the valence electrons in a covalently bonded species.
• The “octet rule” refers to the tendency of atoms to gain a valence shell with a total of 8 electrons.
• Some atoms, like Be and B, might form stable compounds with incomplete octets of electrons.
• Resonance structures occur when there is more than one possible position for a double bond in a molecule.
• Shapes of species are determined by the repulsion of electron pairs according to VSEPR theory.
• Carbon and silicon form giant covalent/network covalent structures

• Intermolecular forces include London (dispersion) forces, dipole-dipole forces and hydrogen bonding.
• The relative strengths of these interactions are London (dispersion) forces < dipole-dipole forces < hydrogen bonds.

Metallic bonding

• A metallic bond is the electrostatic attraction between a lattice of positive ions and delocalized electrons.
• The strength of a metallic bond depends on the charge of the ions and the radius of the metal ion.
• Alloys usually contain more than one metal and have enhanced properties.

• Heat is a form of energy.
• Temperature is a measure of the average kinetic energy of the particles.
• Total energy is conserved in chemical reactions.
• Chemical reactions that involve transfer of heat between the system and the surroundings are described as endothermic or exothermic.
• The enthalpy change (ΔH) for chemical reactions is indicated in kJ mol^-1.
• ΔH values are usually expressed under standard conditions, given by ΔH°, including standard states.

• “The enthalpy change for a reaction that is carried out in a series of steps is equal to the sum of the enthalpy changes for the individual steps.”

• “Bond-forming releases energy and bond-breaking requires energy.”
• “Average bond enthalpy is the energy needed to break one mol of a bond in a gaseous molecule averaged over similar compounds.”

• Species react as a result of collisions of sufficient energy and proper orientation.
• The rate of reaction is expressed as the change in concentration of a particular reactant/product per unit time.
• Concentration changes in a reaction can be followed indirectly by monitoring changes in mass, volume and colour.
• Activation energy (E_a) is the minimum energy that colliding molecules need in order to have successful collisions leading to a reaction.
• By decreasing E_a, a catalyst increases the rate of a chemical reaction, without itself being permanently chemically changed.

• “A state of equilibrium is reached in a closed system when the rates of the forward and reverse reactions are equal.”
• “The equilibrium law describes how the equilibrium constant (Kc) can be determined for a particular chemical reaction.”
• “The magnitude of the equilibrium constant indicates the extent of a reaction at equilibrium and is temperature dependent.”
• “The reaction quotient (Q) measures the relative amount of products and reactants present during a reaction at a particular point in time. Q is the equilibrium expression with non-equilibrium concentrations. The position of the equilibrium changes with changes in concentration, pressure, and temperature.”
• “A catalyst has no effect on the position of equilibrium or the equilibrium constant.”

• “A Brønsted–Lowry acid is a proton/H+ donor and a Brønsted–Lowry base is a proton/H+ acceptor.”
• “Amphiprotic species can act as both Brønsted–Lowry acids and bases.”
• “A pair of species differing by a single proton is called a conjugate acid-base pair.”

• “Most acids have observable characteristic chemical reactions with reactive metals, metal oxides, metal hydroxides, hydrogen carbonates and carbonates.”
• “Salt and water are produced in exothermic neutralization reactions.”

• “pH = − log[H+(aq)] and [H+] = 10−pH.”
• “A change of one pH unit represents a 10-fold change in the hydrogen ion concentration [𝐻𝐻+].”
• “pH values distinguish between acidic, neutral and alkaline solutions.”
• “The ionic product constant, 𝐾𝐾𝑤𝑤 = [H+][OH−] = 10−14 at 298 K.”

• “Strong and weak acids and bases differ in the extent of ionization.”
• “Strong acids and bases of equal concentrations have higher conductivities than weak acids and bases.”
• “A strong acid is a good proton donor and has a weak conjugate base.”
• “A strong base is a good proton acceptor and has a weak conjugate acid.”

• “Rain is naturally acidic because of dissolved CO2 and has a pH of 5.6. Acid deposition has a pH below 5.6.”
• “Acid deposition is formed when nitrogen or sulfur oxides dissolve in water to form HNO3, HNO2, H2SO4 and H2SO3.”
• “Sources of the oxides of sulfur and nitrogen and the effects of acid deposition should be covered.”

• “Oxidation and reduction can be considered in terms of oxygen gain/hydrogen loss, electron transfer or change in oxidation number.”
• “An oxidizing agent is reduced and a reducing agent is oxidized.”
• “Variable oxidation numbers exist for transition metals and for most main-group non-metals.”
• “The activity series ranks metals according to the ease with which they undergo oxidation.”
• “The Winkler Method can be used to measure biochemical oxygen demand (BOD), used as a measure of the degree of pollution in a water sample.”

Voltaic (Galvanic) cells

• “Voltaic cells convert energy from spontaneous, exothermic chemical processes to electrical energy.”
• “Oxidation occurs at the anode (negative electrode) and reduction occurs at the cathode (positive electrode) in a voltaic cell.”

Electrolytic cells

• “Electrolytic cells convert electrical energy to chemical energy, by bringing about non-spontaneous processes.”
• “Oxidation occurs at the anode (positive electrode) and reduction occurs at the cathode (negative electrode) in an electrolytic cell.”

• “A homologous series is a series of compounds of the same family, with the same general formula, which differ from each other by a common structural unit.”
• “Structural formulas can be represented in full and condensed format.”
• “Structural isomers are compounds with the same molecular formula but different arrangements of atoms.”
• “Functional groups are the reactive parts of molecules.”
• “Saturated compounds contain single bonds only and unsaturated compounds contain double or triple bonds.”
• “Benzene is an aromatic, unsaturated hydrocarbon.”

Alkanes:

• “Alkanes have low reactivity and undergo free-radical substitution reactions.”

Alkenes:

• “Alkenes are more reactive than alkanes and undergo addition reactions. Bromine water can be used to distinguish between alkenes and alkanes.”

Alcohols:

• “Alcohols undergo nucleophilic substitution reactions with acids (also called esterification or condensation) and some undergo oxidation reactions.”

Halogenoalkanes:

• “Halogenoalkanes are more reactive than alkanes. They can undergo (nucleophilic) substitution reactions. A nucleophile is an electron-rich species containing a lone pair that it donates to an electron-deficient carbon.”

Polymers:

• “Addition polymers consist of a wide range of monomers and form the basis of the plastics industry.”

Benzene:

• “Benzene does not readily undergo addition reactions but does undergo electrophilic substitution reactions.”

• “Qualitative data includes all non-numerical information obtained from observations not from measurement.”
• “Quantitative data are obtained from measurements, and are always associated with random errors/uncertainties, determined by the apparatus, and by human limitations such as reaction times.”
• “Propagation of random errors in data processing shows the impact of the uncertainties on the final result.”
• “Experimental design and procedure usually lead to systematic errors in measurement, which cause a deviation in a particular direction.”
• “Repeat trials and measurements will reduce random errors but not systematic errors.”

• “Graphical techniques are an effective means of communicating the effect of an independent variable on a dependent variable, and can lead to determination of physical quantities.”
• “Sketched graphs have labeled but unscaled axes, and are used to show qualitative trends, such as variables that are proportional or inversely proportional.”
• “Drawn graphs have labeled and scaled axes, and are used in quantitative measurements.”

• “The degree of unsaturation or index of hydrogen deficiency (IHD) can be used to determine from a molecular formula the number of rings or multiple bonds in a molecule.”
• “Mass spectrometry (MS), proton nuclear magnetic resonance spectroscopy (1H NMR) and infrared spectroscopy (IR) are techniques that can be used to help identify compounds and to determine their structure.”

• “In an emission spectrum, the limit of convergence at higher frequency corresponds to the first ionization energy.”
• “Trends in first ionization energy across periods account for the existence of main energy levels and sub-levels in atoms.”
• “Successive ionization energy data for an element give information that shows relations to electron configurations.”

• “Transition elements have variable oxidation states, form complex ions with ligands, have coloured compounds, and display catalytic and magnetic properties.”
• “Zn is not considered to be a transition element as it does not form ions with incomplete d-orbitals.”
• “Transition elements show an oxidation state of +2 when the s-electrons are removed.”

• “The d sub-level splits into two sets of orbitals of different energy in a complex ion.”
• “Complexes of d-block elements are coloured, as light is absorbed when an electron is excited between the d-orbitals.”
• “The colour absorbed is complementary to the colour observed.”

• “Covalent bonds result from the overlap of atomic orbitals. A sigma bond (σ) is formed by the direct head-on/end-to-end overlap of atomic orbitals, resulting in electron density concentrated between the nuclei of the bonding atoms. A pi bond (π) is formed by the sideways overlap of atomic orbitals, resulting in electron density above and below the plane of the nuclei of the bonding atoms.”
• “Formal charge (FC) can be used to decide which Lewis (electron dot) structure is preferred from several. The FC is the charge an atom would have if all atoms in the molecule had the same electronegativity. FC = (Number of valence electrons)-½(Number of bonding electrons)-(Number of non-bonding electrons). The Lewis (electron dot) structure with the atoms having FC values closest to zero is preferred.”
• “Exceptions to the octet rule include some species having incomplete octets and expanded octets.”
• “Delocalization involves electrons that are shared by/between all atoms in a molecule or ion as opposed to being localized between a pair of atoms.”
• “Resonance involves using two or more Lewis (electron dot) structures to represent a particular molecule or ion. A resonance structure is one of two or more alternative Lewis (electron dot) structures for a molecule or ion that cannot be described fully with one Lewis (electron dot) structure alone.”

• “A hybrid orbital results from the mixing of different types of atomic orbitals on the same atom.”

• “Representative equations (eg M^+(g) → M^+(aq)) can be used for enthalpy/energy of hydration, ionization, atomization, electron affinity, lattice, covalent bond and solution.”
• “Enthalpy of solution, hydration enthalpy and lattice enthalpy are related in an energy cycle.”

• “Entropy (S) refers to the distribution of available energy among the particles. The more ways the energy can be distributed the higher the entropy.”
• “Gibbs free energy (G) relates the energy that can be obtained from a chemical reaction to the change in enthalpy (ΔH), change in entropy (ΔS), and absolute temperature (T).”
• “Entropy of gas>liquid>solid under same conditions.”

• “Reactions may occur by more than one step and the slowest step determines the rate of reaction (rate determining step/RDS).”
• “The molecularity of an elementary step is the number of reactant particles taking part in that step.”
• “The order of a reaction can be either integer or fractional in nature. The order of a reaction can describe, with respect to a reactant, the number of particles taking part in the rate-determining step.”
• “Rate equations can only be determined experimentally.”
• “The value of the rate constant (k) is affected by temperature and its units are determined from the overall order of the reaction.”
• “Catalysts alter a reaction mechanism, introducing a step with lower activation energy.”

Activation energy (HL ONLY)

• “The Arrhenius equation uses the temperature dependence of the rate constant to determine the activation energy.”
• “A graph of 1/T against ln k is a linear plot with gradient – Ea / R and intercept, lnA.”
• “The frequency factor (or pre-exponential factor) (A) takes into account the frequency of collisions with proper orientations.”

• “Le Châtelier’s principle for changes in concentration can be explained by the equilibrium law.”
• “The position of equilibrium corresponds to a maximum value of entropy and a minimum in the value of the Gibbs free energy.”
• “The Gibbs free energy change of a reaction and the equilibrium constant can both be used to measure the position of an equilibrium reaction and are related by the equation, ∆G° = −RT ln(𝐾)”

• “A Lewis acid is a lone pair acceptor and a Lewis base is a lone pair donor.”
• “When a Lewis base reacts with a Lewis acid a coordinate bond is formed.”
• “A nucleophile is a Lewis base and an electrophile is a Lewis acid.”

• “The expression for the dissociation constant of a weak acid (Ka) and a weak base (Kb).”
• “For a conjugate acid base pair, Ka × Kb = Kw.”
• “The relationship between Ka and pKa is (pKa = -log Ka), and between Kb and pKb is (pKb = -log Kb).”

• “The characteristics of the pH curves produced by the different combinations of strong and weak acids and bases.”
• “An acid–base indicator is a weak acid or a weak base where the components of the conjugate acid–base pair have different colours.”
• “The relationship between the pH range of an acid–base indicator, which is a weak acid, and its pKa value.”
• “The buffer region on the pH curve represents the region where small additions of acid or base result in little or no change in pH.”
• “The composition and action of a buffer solution.”

• “A voltaic cell generates an electromotive force (EMF) resulting in the movement of electrons from the anode (negative electrode) to the cathode (positive electrode) via the external circuit. The EMF is termed the cell potential (Eº).”
• “The standard hydrogen electrode (SHE) consists of an inert platinum electrode in contact with 1 mol dm-3 hydrogen ion and hydrogen gas at 100 kPa and 298 K. The standard electrode potential (Eº) is the potential (voltage) of the reduction half-equation under standard conditions measured relative to the SHE. Solute concentration is 1 mol dm-3 or 100 kPa for gases. Eº of the SHE is 0 V.”
• “When aqueous solutions are electrolysed, water can be oxidized to oxygen at the anode and reduced to hydrogen at the cathode.
• “ΔGº = –nFEº. When Eº is positive, ΔGº is negative indicative of a spontaneous process. When Eº is negative, ΔGº is positive indicative of a non-spontaneous process. When Eº is 0, then ΔGº is 0.”
• “Current, duration of electrolysis and charge on the ion affect the amount of product formed at the electrodes during electrolysis.”
• “Electroplating involves the electrolytic coating of an object with a metallic thin layer.”

Nucleophilic Substitution Reactions:

• “SN1 represents a nucleophilic unimolecular substitution reaction and SN2 represents a nucleophilic bimolecular substitution reaction. SN1 involves a carbocation intermediate. SN2 involves a concerted reaction with a transition state.”
• “For tertiary halogenoalkanes the predominant mechanism is SN1 and for primary halogenoalkanes it is SN2. Both mechanisms occur for secondary halogenoalkanes.”
• “The rate determining step (slow step) in an SN1 reaction depends only on the concentration of the halogenoalkane, rate = k[halogenoalkane]. For SN2, rate = k[halogenoalkane][nucleophile]. SN2 is stereospecific with an inversion of configuration at the carbon.”
• “SN2 reactions are best conducted using aprotic, non-polar solvents and SN1 reactions are best conducted using protic, polar solvents.”

Electrophilic Addition Reactions:

• “An electrophile is an electron-deficient species that can accept electron pairs from a nucleophile. Electrophiles are Lewis acids.”
• “Markovnikov’s rule can be applied to predict the major product in electrophilic addition reactions of unsymmetrical alkenes with hydrogen halides and interhalogens. The formation of the major product can be explained in terms of the relative stability of possible carbocations in the reaction mechanism.”

Electrophilic Substitution Reactions:

• “Benzene is the simplest aromatic hydrocarbon compound (or arene) and has a delocalized structure of π bonds around its ring. Each carbon to carbon bond has a bond order of 1.5. Benzene is susceptible to attack by electrophiles.”

Reduction Reactions:

• “Carboxylic acids can be reduced to primary alcohols (via the aldehyde). Ketones can be reduced to secondary alcohols. Typical reducing agents are lithium aluminum hydride (used to reduce carboxylic acids) and sodium borohydride.”

• “The synthesis of an organic compound stems from a readily available starting material via a series of discrete steps. Functional group interconversions are the basis of such synthetic routes.”
• “Retro-synthesis of organic compounds.”

• “Stereoisomers are subdivided into two classes—conformational isomers, which interconvert by rotation about a σ bond and configurational isomers that interconvert only by breaking and reforming a bond. Configurational isomers are further subdivided into cis-trans and E/Z isomers and optical isomers.”

• “Cis-trans isomers can occur in alkenes or cycloalkanes (or heteroanalogues) and differ in the positions of atoms (or groups) relative to a reference plane. According to IUPAC, E/Z isomers refer to alkenes of the form R1R2C=CR3R4 (R1 ≠ R2, R3 ≠ R4) where neither R1 nor R2 need be different from R3 or R4.”
• “A chiral carbon is a carbon joined to four different atoms or groups.”
• “An optically active compound can rotate the plane of polarized light as it passes through a solution of the compound. Optical isomers are enantiomers. Enantiomers are non-superimposeable mirror images of each other. Diastereomers are not mirror images of each other.”
• “A racemic mixture (or racemate) is a mixture of two enantiomers in equal amounts and is optically inactive.”

• “Structural identification of compounds involves several different analytical techniques including IR, 1H NMR and MS.”
• “In a high resolution 1H NMR spectrum, single peaks present in low resolution can split into further clusters of peaks.”
• “The structural technique of single crystal X-ray crystallography can be used to identify the bond lengths and bond angles of crystalline compounds.”

• “Materials are classified based on their uses, properties, or bonding and structure.”
• “The properties of a material based on the degree of covalent, ionic or metallic character in a compound can be deduced from its position on a bonding triangle.”
• “Composites are mixtures in which materials are composed of two distinct phases, a reinforcing phase that is embedded in a matrix phase.”

• “Reduction by coke (carbon), a more reactive metal, or electrolysis are means of obtaining some metals from their ores.”
• “The relationship between charge and the number of moles of electrons is given by Faraday’s constant, F.
• “Alloys are homogeneous mixtures of metals with other metals or non-metals.”
• “Diamagnetic and paramagnetic compounds differ in electron spin pairing and their behaviour in magnetic fields.”
• “Trace amounts of metals can be identified and quantified by ionizing them with argon gas plasma in Inductively Coupled Plasma (ICP) Spectroscopy using Mass Spectroscopy ICP-MS and Optical Emission Spectroscopy ICP-OES.”

• “Reactants adsorb onto heterogeneous catalysts at active sites and the products desorb.”
• “Homogeneous catalysts chemically combine with the reactants to form a temporary activated complex or a reaction intermediate.”
• “Transition metal catalytic properties depend on the adsorption/absorption properties of the metal and the variable oxidation states.”
• “Zeolites act as selective catalysts because of their cage structure.”
• “Catalytic particles are nearly always nanoparticles that have large surface areas per unit mass.”

• “Liquid crystals are fluids that have physical properties (electrical, optical and elasticity) that are dependent on molecular orientation to some fixed axis in the material.”
• “Thermotropic liquid-crystal materials are pure substances that show liquid crystal behaviour over a temperature range.”
• “Lyotropic liquid crystals are solutions that show the liquid-crystal state over a (certain) range of concentrations.”
• “Nematic liquid crystal phase is characterized by rod shaped molecules which are randomly distributed but on average align in the same direction.”

• “Thermoplastics soften when heated and harden when cooled.”
• “A thermosetting polymer is a prepolymer in a soft solid or viscous state that changes irreversibly into a hardened thermoset by curing.”
• “Elastomers are flexible and can be deformed under force but will return to nearly their original shape once the stress is released.”
• “High density polyethene (HDPE) has no branching allowing chains to be packed together.”
• “Low density polyethene (LDPE) has some branching and is more flexible.”
• “Plasticizers added to a polymer increase the flexibility by weakening the intermolecular forces between the polymer chains.”
• “Atom economy is a measure of efficiency applied in green chemistry.”
• “Isotactic addition polymers have substituents on the same side.”
• “Atactic addition polymers have the substituents randomly placed.”

• “Molecular self-assembly is the bottom-up assembly of nanoparticles and can occur by selectively attaching molecules to specific surfaces. Self-assembly can also occur spontaneously in solution.”
• “Possible methods of producing nanotubes are arc discharge, chemical vapour deposition (CVD) and high pressure carbon monoxide (HIPCO).”
• “Arc discharge involves either vaporizing the surface of one of the carbon electrodes, or discharging an arc through metal electrodes submersed in a hydrocarbon solvent, which forms a small rod-shaped deposit on the anode.”

• “Plastics do not degrade easily because of their strong covalent bonds.”
• “Burning of polyvinyl chloride releases dioxins, HCl gas and incomplete hydrocarbon combustion products.”
• “Dioxins contain unsaturated six-member heterocyclic rings with two oxygen atoms, usually in positions 1 and 4.”
• “Chlorinated dioxins are hormone disrupting, leading to cellular and genetic damage.”
• “Plastics require more processing to be recycled than other materials.”
• “Plastics are recycled based on different resin types.”

• “Superconductors are materials that offer no resistance to electric currents below a critical temperature.”
• “The Meissner effect is the ability of a superconductor to create a mirror image magnetic field of an external field, thus expelling it.”
• “Resistance in metallic conductors is caused by collisions between electrons and positive ions of the lattice.”
• “The Bardeen–Cooper–Schrieffer (BCS) theory explains that below the critical temperature electrons in superconductors form Cooper pairs which move freely through the superconductor.”
• “Type 1 superconductors have sharp transitions to superconductivity whereas Type 2 superconductors have more gradual transitions.”
• “X-ray diffraction can be used to analyse structures of metallic and ionic compounds.”
• “Crystal lattices contain simple repeating unit cells.”
• “Atoms on faces and edges of unit cells are shared.”
• “The number of nearest neighbours of an atom/ion is its coordination number.”

• “Condensation polymers require two functional groups on each monomer.”
• “NH3, HCl and H2O are possible products of condensation reactions.”
• “Kevlar® is a polyamide with a strong and ordered structure. The hydrogen bonds between O and N can be broken with the use of concentrated sulfuric acid.”

• “Toxic doses of transition metals can disturb the normal oxidation/reduction balance in cells through various mechanisms.”
• “Some methods of removing heavy metals are precipitation, adsorption, and chelation.”
• “Polydentate ligands form more stable complexes than similar monodentate ligands due to the chelate effect, which can be explained by considering entropy changes.”

• “The diverse functions of biological molecules depend on their structures and shapes.”
• “Metabolic reactions take place in highly controlled aqueous environments.”
• “Reactions of breakdown are called catabolism and reactions of synthesis are called anabolism.”
• “Biopolymers form by condensation reactions and are broken down by hydrolysis reactions.”
• “Photosynthesis is the synthesis of energy-rich molecules from carbon dioxide and water using light energy.”
• “Respiration is a complex set of metabolic processes providing energy for cells.”

• “Proteins are polymers of 2-amino acids, joined by amide links (also known as peptide bonds).”
• “Amino acids are amphoteric and can exist as zwitterions, cations and anions.”
• “Protein structures are diverse and are described at the primary, secondary, tertiary and quaternary levels.”
• “A protein’s three-dimensional shape determines its role in structural components or in metabolic processes.”
• “Most enzymes are proteins that act as catalysts by binding specifically to a substrate at the active site.”
• “As enzyme activity depends on the conformation, it is sensitive to changes in temperature and pH and the presence of heavy metal ions.”
• “Chromatography separation is based on different physical and chemical principles.”

• “Fats are more reduced than carbohydrates and so yield more energy when oxidized.”
• “Triglycerides are produced by condensation of glycerol with three fatty acids and contain ester links. Fatty acids can be saturated, monounsaturated or polyunsaturated.”
• “Phospholipids are derivatives of triglycerides.”
• “Hydrolysis of triglycerides and phospholipids can occur using enzymes or in alkaline or acidic conditions.”
• “Steroids have a characteristic fused ring structure, known as a steroidal backbone.”
• “Lipids act as structural components of cell membranes, in energy storage, thermal and electrical insulation, as transporters of lipid soluble vitamins and as hormones.”

• “Carbohydrates have the general formula Cx(H2O)y.”
• “Haworth projections represent the cyclic structures of monosaccharides.”
• “Monosaccharides contain either an aldehyde group (aldose) or a ketone group (ketose) and several –OH groups.”
• “Straight chain forms of sugars cyclize in solution to form ring structures containing an ether linkage.”
• “Glycosidic bonds form between monosaccharides forming disaccharides and polysaccharides.”
• “Carbohydrates are used as energy sources and energy reserves.”

• “Vitamins are organic micronutrients which (mostly) cannot be synthesized by the body but must be obtained from suitable food sources.”
• “The solubility (water or fat) of a vitamin can be predicted from its structure.”
• “Most vitamins are sensitive to heat.”
• “Vitamin deficiencies in the diet cause particular diseases and affect millions of people worldwide.”

• “Xenobiotics refer to chemicals that are found in an organism that are not normally present there.”
• “Biodegradable/compostable plastics can be consumed or broken down by bacteria or other living organisms.”
• “Host–guest chemistry involves the creation of synthetic host molecules that mimic some of the actions performed by enzymes in cells, by selectively binding to specific guest species, such as toxic materials in the environment.”
• “Enzymes have been developed to help in the breakdown of oil spills and other industrial wastes.”
• “Enzymes in biological detergents can improve energy efficiency by enabling effective cleaning at lower temperatures.”
• “Biomagnification is the increase in concentration of a substance in a food chain.”
• “Green chemistry, also called sustainable chemistry, is an approach to chemical research and engineering that seeks to minimize the production and release to the environment of hazardous substances.”

• “Inhibitors play an important role in regulating the activities of enzymes.”
• “Amino acids and proteins can act as buffers in solution.”
• “Protein assays commonly use UV-vis spectroscopy and a calibration curve based on known standards.”

• “Nucleotides are the condensation products of a pentose sugar, phosphoric acid and a nitrogenous base—adenine (A), guanine (G), cytosine (C), thymine (T) or uracil (U).”
• “Polynucleotides form by condensation reactions.”
• “DNA is a double helix of two polynucleotide strands held together by hydrogen bonds.”
• “RNA is usually a single polynucleotide chain that contains uracil in place of thymine, and a sugar ribose in place of deoxyribose.”
• “The sequence of bases in DNA determines the primary structure of proteins synthesized by the cell using a triplet code, known as the genetic code, which is universal.”
• “Genetically modified organisms have genetic material that has been altered by genetic engineering techniques, involving transferring DNA between species.”

• “Biological pigments are coloured compounds produced by metabolism.”
• “The colour of pigments is due to highly conjugated systems with delocalized electrons, which have intense absorption bands in the visible region.”
• “Porphyrin compounds, such as hemoglobin, myoglobin, chlorophyll and many cytochromes are chelates of metals with large nitrogen-containing macrocyclic ligands.”
• “Hemoglobin and myoglobin contain heme groups with the porphyrin group bound to an iron(II) ion.”
• “Cytochromes contain heme groups in which the iron ion interconverts between iron(II) and iron(III) during redox reactions.”
• “Anthocyanins are aromatic, water-soluble pigments widely distributed in plants. Their specific colour depends on metal ions and pH.”
• “Carotenoids are lipid-soluble pigments, and are involved in harvesting light in photosynthesis. They are susceptible to oxidation, catalysed by light.”

• “With one exception, amino acids are chiral, and only the L-configuration is found in proteins.”
• “Naturally occurring unsaturated fat is mostly in the cis form, but food processing can convert it into the trans form.”
• “D and L stereoisomers of sugars refer to the configuration of the chiral carbon atom furthest from the aldehyde or ketone group, and D forms occur most frequently in nature.”
• “Ring forms of sugars have isomers, known as α and β, depending on whether the position of the hydroxyl group at carbon 1 (glucose) or carbon 2 (fructose) lies below the plane of the ring (α) or above the plane of the ring (β).”
• “Vision chemistry involves the light activated interconversion of cis- and trans- isomers of retinal.”

• “A useful energy source releases energy at a reasonable rate and produces minimal pollution.”
• “The quality of energy is degraded as heat is transferred to the surroundings. Energy and materials go from a concentrated into a dispersed form. The quantity of the energy available for doing work decreases.”
• “Renewable energy sources are naturally replenished. Non-renewable energy sources are finite.”
• “Energy density = energy released from fuel volume of fuel consumed.”
• “Specific energy = energy released from fuel mass of fuel consumed.”
• “The effeciency of an energy transfer = useful output energy total input energy x 100%.”

• “Fossil fuels were formed by the reduction of biological compounds that contain carbon, hydrogen, nitrogen, sulfur and oxygen.”
• “Petroleum is a complex mixture of hydrocarbons that can be split into different component parts called fractions by fractional distillation.”
• “Crude oil needs to be refined before use. The different fractions are separated by a physical process in fractional distillation.”
• “The tendency of a fuel to auto-ignite, which leads to “knocking” in a car engine, is related to molecular structure and measured by the octane number.”
• “The performance of hydrocarbons as fuels is improved by the cracking and catalytic reforming reactions.”
• “Coal gasification and liquefaction are chemical processes that convert coal to gaseous and liquid hydrocarbons.”
• “A carbon footprint is the total amount of greenhouse gases produced during human activities. It is generally expressed in equivalent tons of carbon dioxide.”

Nuclear fusion

• “Light nuclei can undergo fusion reactions as this increases the binding energy per nucleon.”
• “Fusion reactions are a promising energy source as the fuel is inexpensive and abundant, and no radioactive waste is produced.”
• “Absorption spectra are used to analyse the composition of stars.”

Nuclear fission

• “Heavy nuclei can undergo fission reactions as this increases the binding energy per nucleon.”
• “235U undergoes a fission chain reaction: U235 92 + n10 → U 236 92 → X + Y + neutrons.”
• “The critical mass is the mass of fuel needed for the reaction to be self-sustaining.”
• “239Pu, used as a fuel in “breeder reactors”, is produced from 238U by neutron capture.”
• “Radioactive waste may contain isotopes with long and short half-lives.”
• “Half-life is the time it takes for half the number of atoms to decay.”

• “Light can be absorbed by chlorophyll and other pigments with a conjugated electronic structure.”
• “Photosynthesis converts light energy into chemical energy: 6CO2 + 6H2O ==> C6H12O6 + 6O2”
• “Fermentation of glucose produces ethanol which can be used as a biofuel: C6H12O6 ==> 2C2H5OH + 2CO2.”
• “Energy content of vegetable oils is similar to that of diesel fuel but they are not used in internal combustion engines as they are too viscous.”
• “Transesterification between an ester and an alcohol with a strong acid or base catalyst produces a different ester: RCOOR1 + R2OH ==> RCOOR2 + R1OH.”
• “In the transesterification process, involving a reaction with an alcohol in the presence of a strong acid or base, the triglyceride vegetable oils are converted to a mixture mainly comprising of alkyl esters and glycerol, but with some fatty acids.”
• “Transesterification with ethanol or methanol produces oils with lower viscosity that can be used in diesel engines.”

• “Greenhouse gases allow the passage of incoming solar short wavelength radiation but absorb the longer wavelength radiation from the Earth. Some of the absorbed radiation is re-radiated back to Earth.”
• “There is a heterogeneous equilibrium between concentration of atmospheric carbon dioxide and aqueous carbon dioxide in the oceans.”
• “Greenhouse gases absorb IR radiation as there is a change in dipole moment as the bonds in the molecule stretch and bend.”
• “Particulates such as smoke and dust cause global dimming as they reflect sunlight, as do clouds.”

• “An electrochemical cell has internal resistance due to the finite time it takes for ions to diffuse. The maximum current of a cell is limited by its internal resistance.”
• “The voltage of a battery depends primarily on the nature of the materials used while the total work that can be obtained from it depends on their quantity.”
• “In a primary cell the electrochemical reaction is not reversible. Rechargeable cells involve redox reactions that can be reversed using electricity.”
• “A fuel cell can be used to convert chemical energy, contained in a fuel that is consumed, directly to electrical energy.”
• “Microbial fuel cells (MFCs) are a possible sustainable energy source using different carbohydrates or substrates present in waste waters as the fuel.”
• “The Nernst equation can be used to calculate the potential of a half-cell in an electrochemical cell, under non-standard conditions.”
• “The electrodes in a concentration cell are the same but the concentration of the electrolyte solutions at the cathode and anode are different.”

Nuclear fusion:

• “The mass defect (∆m) is the difference between the mass of the nucleus and the sum of the masses of its individual nucleons.”
• “The nuclear binding energy (ΔE) is the energy required to separate a nucleus into protons and neutrons.”

Nuclear fission:

• “The energy produced in a fission reaction can be calculated from the mass difference between the products and reactants using the Einstein mass–energy equivalence relationship 𝐸 = 𝑚c^2.”
• “The different isotopes of uranium in uranium hexafluoride can be separated, using diffusion or centrifugation causing fuel enrichment.”
• “The effusion rate of a gas is inversely proportional to the square root of the molar mass (Graham’s Law).”
• “Radioactive decay is kinetically a first order process with the half-life related to the decay constant by the equation 𝜆 = ln 2 /𝑡1 .”
• “The dangers of nuclear energy are due to the ionizing nature of the radiation it produces which leads to the production of oxygen free radicals such as superoxide (O2-), and hydroxyl (HO·). These free radicals can initiate chain reactions that can damage DNA and enzymes in living cells.”

• “Molecules with longer conjugated systems absorb light of longer wavelength.”
• “The electrical conductivity of a semiconductor increases with an increase in temperature whereas the conductivity of metals decreases.”
• “The conductivity of silicon can be increased by doping to produce n-type and p- type semiconductors.”
• “Solar energy can be converted to electricity in a photovoltaic cell.”
• “DSSCs imitate the way in which plants harness solar energy. Electrons are “injected” from an excited molecule directly into the TiO2 semiconductor.”
• “The use of nanoparticles coated with light-absorbing dye increases the effective surface area and allows more light over a wider range of the visible spectrum to be absorbed.”

• “In animal studies, the therapeutic index is the lethal dose of a drug for 50% of the population (LD50) divided by the minimum effective dose for 50% of the population (ED50).”
• “In humans, the therapeutic index is the toxic dose of a drug for 50% of the population (TD50) divided by the minimum effective dose for 50% of the population (ED50).”
• “The therapeutic window is the range of dosages between the minimum amounts of the drug that produce the desired effect and a medically unacceptable adverse effect.”
• “Dosage, tolerance, addiction and side effects are considerations of drug administration.”
• “Bioavailability is the fraction of the administered dosage that reaches the target part of the human body.”
• “The main steps in the development of synthetic drugs include identifying the need and structure, synthesis, yield and extraction.”
• “Drug–receptor interactions are based on the structure of the drug and the site of activity.”

Aspirin:

• “Mild analgesics function by intercepting the pain stimulus at the source, often by interfering with the production of substances that cause pain, swelling or fever.”
• “Aspirin is prepared from salicylic acid.”
• “Aspirin can be used as an anticoagulant, in prevention of the recurrence of heart attacks and strokes and as a prophylactic.”

Penicillin:

• “Penicillins are antibiotics produced by fungi.”
• “A beta-lactam ring is a part of the core structure of penicillins.”
• “Some antibiotics work by preventing cross-linking of the bacterial cell walls.”
• “Modifying the side-chain results in penicillins that are more resistant to the penicillinase enzyme.”

• “The ability of a drug to cross the blood–brain barrier depends on its chemical structure and solubility in water and lipids.”
• “Opiates are natural narcotic analgesics that are derived from the opium poppy.”
• “Morphine and codeine are used as strong analgesics. Strong analgesics work by temporarily bonding to receptor sites in the brain, preventing the transmission of pain impulses without depressing the central nervous system.”
• “Medical use and addictive properties of opiate compounds are related to the presence of opioid receptors in the brain.”

• “Non-specific reactions, such as the use of antacids, are those that work to reduce the excess stomach acid.”
• “Active metabolites are the active forms of a drug after it has been processed by the body.”

• “Viruses lack a cell structure and so are more difficult to target with drugs than bacteria.”
• “Antiviral drugs may work by altering the cell’s genetic material so that the virus cannot use it to multiply. Alternatively, they may prevent the viruses from multiplying by blocking enzyme activity within the host cell.”

• “High-level waste (HLW) is waste that gives off large amounts of ionizing radiation for a long time.”
• “Low-level waste (LLW) is waste that gives off small amounts of ionizing radiation for a short time.”
• “Antibiotic resistance occurs when micro-organisms become resistant to antibacterials.”

• “Taxol is a drug that is commonly used to treat several different forms of cancer.”
• “Taxol naturally occurs in yew trees but is now commonly synthetically produced.”
• “A chiral auxiliary is an optically active substance that is temporarily incorporated into an organic synthesis so that it can be carried out asymmetrically with the selective formation of a single enantiomer.”

• “Alpha, beta, gamma, proton, neutron and positron emissions are all used for medical treatment.”
• “Magnetic resonance imaging (MRI) is an application of NMR technology.”
• “Radiotherapy can be internal and/or external.”
• “Targeted Alpha Therapy (TAT) and Boron Neutron Capture Therapy (BNCT) are two methods which are used in cancer treatment.”

• “Organic structures can be analysed and identified through the use of infrared spectroscopy, mass spectroscopy and proton NMR.”
• “The presence of alcohol in a sample of breath can be detected through the use of either a redox reaction or a fuel cell type of breathalyser.”