Key Words

Tali Skipper
Flashcards by Tali Skipper, updated more than 1 year ago
Tali Skipper
Created by Tali Skipper about 5 years ago


All key words for the 1st year of A-level OCR A Chemistry.

Resource summary

Question Answer
Accuracy How close to the true value a measurement is.
Acid A chemical that is a proton donor. Releases H+ (aq) in solution.
Activation Energy The minimum energy required to start a reaction by breaking chemical bonds in the reactants.
Aim Identifies the purpose of an investigation. What is trying to be found out.
Alcohol A group of organic compounds with the functional group -OH.
Alicyclic Hydrocarbon. Carbon atoms are joined in a ring structure.
Alkali Soluble in water releasing OH- (aq) Ions.
Alkanes Homologous series of saturated hydrocarbons.
Alkenes A homologous series of unsaturated hydrocarbons.
Amount of Substance The quantity whose unit is the mole. It is a way of counting atoms.
Aliphatic Hydrocarbons A hydrocarbon where carbon atoms are joined together in straight or branched chains.
Anhydrous A substance that contains no water molecules.
Anion Negatively charged ion.
Anomalies/ Anomalous Data that doesn't fit the particular trend of data and doesn't follow the general pattern.
Aqueous A solution with water as the solvent.
Aromatic Hydrocarbons Contain at least 1 benzene ring (ring of 6 carbons).
Atom Composed of electrons and a central nucleus of protons and neutrons.
Atomic Number The number of protons in the nucleus of an atom.
Atomic Orbital A region of space where a maximum of 2 electrons with opposite spins in each can be found.
Atomic Radius The distance from the nucleus to the boundary of the surrounding cloud of electrons.
Average Bond Enthalpy The mean energy needed for 1 mole of a given type of gaseous bonds to undergo homolytic fission.
Avogadro Constant The number of atoms per mole of the carbon-12 isotope = 6.02 X 10^23 mol^-1
Base A chemical that can react with acids and is a proton acceptor.
Biodegradable Materials Decompose by microorganisms and environmental conditions.
Biological Catalysts Enzymes - Catalyse reactions in the body.
Bioplastics Materials made from a renewable source that are biodegradable.
Boltzmann Distribution The distribution of energies of molecules at a particular temperature, often shown as a graph.
Bond Angle The angle that is formed between to adjacent bonds on the same atom.
Bonded Pair A pair of electrons that have been shared between two chemically bonded atoms.
Bonding Region The space where an electron can be found in a bond.
Carbonyls An organic molecule which contains the C=O functional group.
Carboxylic Acids An organic acid containing a carboxyl functional group –COOH.
Calorimetry The quantitative study of energy change in a chemical reaction.
Catalyst A substance that increases the rate of reaction by decreasing the activation energy. It is not used up in the process.
Categoric Variable A qualitative description of a variable.
Cation Positively charged ion.
CFCs Chlorofluorocarbons are a class of organic compounds that are non-toxic to humans but can be radicalised by UV light.
Chemical Energy A special form of potential energy stored in chemical bonds.
Cis-Trans Isomerism A type of E/Z isomerism where two substituent groups on each carbon are the same.
Collision Theory A model to help understand and make predictions about how changing factors may change the rate of a chemical reaction.
Complete Combustion The oxidising of a fuel in a plentiful supply of oxygen.
Compound A substance formed from 2 or more chemically bonded elements in a fixed ratio.
Concentration Of A Solution The amount of solute dissolved per 1dm^3 of solution.
Concordant Results Values that are close to each other and therefore represent reliable quantitative data.
Continuous Variable A measured value which could be any number.
Control Variable A factor that you must keep constant between experimental runs so that you can compare results.
Covalent Bond A bond formed by a shared pair of electrons between 2 atoms nuclei.
Curly Arrows Model the flow of electron pairs during reaction mechanisms.
Dative Covalent Bond A bond formed by a shared pair of electrons that have been provided by one of the bonding atoms only.
Dehydration A chemical reaction where a water molecule is eliminated from an organic compound.
Delocalised Electrons Electrons that are shared between more than 2 atoms.
Dependent Variable The factor that you observe in an experiment.
Discrete Variables Variables that can only be particular defined numbers.
Displacement Reactions A reaction in which a more reactive element takes the place of a less-reactive element in a compound.
Displayed Formula A formula which Shows the relative positioning of atoms and the bonds between them.
Disproportionation The oxidation and reduction of the same element in a redox reaction.
Distillation A technique used to separate miscible liquids or solutions.
Dot Formulae Gives the ratio between the number of compound molecules and the number of water molecules within the crystalline structure.
Dynamic Equilibrium The equilibrium that exists in a closed system when the rate of the forwards reaction is equal to the rate of the backwards reaction and all the chemicals have a constant concentration.
E/Z Isomerism A type of isomerism that is caused by the restricted rotation around the C=C where 2 different substituent groups are attached to each carbon atom.
Electrical Conductivity The degree to which a specified material allows charge to be carried.
Electron Carries a negative charge. Has a mass of 1/2000 and the number of electrons is equal to the number of protons.
Electron Configuration The arrangement of electrons in an atom or ion.
Electron Shielding The repulsion between electrons in different inner shells. Shielding reduces the net attractive force form the positive nucleus on the outer-shell electrons.
Electronegativity A measure of the attraction of an electron in a covalent bond.
Electrophile An electron-pair acceptor.
Elimination An organic chemical reaction in which one reactant forms two products.
Empirical Formula The simplest whole number ratio of atoms of each element present in a compound.
Endothermic A reaction in which the enthalpy of the products is greater than the enthalpy of the reactants, resulting in heat being taken in from the surroundings. Positive DeltaH.
Enthalpy H The heat content that is stored in a chemical system.
Enthalpy Change of Combustion The energy change that takes place when 1 mole of a substance is completely combusted.
Enthalpy Change Of FormationT The energy change that takes place when 1 mole of a compound is formed from its constituent elements in their standard states under standard conditions.
Enthalpy Change Of Neutralisation The energy change associated with the formation of 1 mole of water from a neutralisation reaction.
Enthalpy Change Of Reaction The energy change associated with a given reaction.
Enthalpy Cycle A pictorial representation showing alternative routes between reactants and products (Hess Law).
Enthalpy Profile Diagrams A diagram of a reaction that allows you to compare the enthalpy of the reactants with the enthalpy of the products.
Equilibrium Constant, Kc Kc shows the position of equilibrium. It Gives the measure of where the equilibrium lays.
Equilibrium Law aA+bB⇌cC+dD Kc= [C]c[D]d [A]a[B]b
Ester A functional group of –COO found in some organic molecules.
Esterification The chemical reaction which forms an ester.
Exothermic A reaction in which the enthalpy of the products is smaller than the enthalpy of the reactants, resulting in heat loss to the surroundings. Negative DeltaH.
Experiment An ordered set of practical steps which are used to test a hypothesis.
Extraneous Variable A factor that is not controlled or measured in an experiment but may introduce error into the results.
False Positive When a positive result is produced but not due to the desired product being formed.
First Ionisation Energy The energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions.
Fragmentation The process in mass spectrometry that causes a positive ion to split into pieces, one of which is a positive fragmented ion.
Functional Group A group of atoms that is responsible for the characteristic chemical reactions of a compound.
General Formula The simplest algebraic formula for a homologous series.
Giant Covalent Lattice A 3D structure of atoms that are all bonded together by strong covalent bonds.
Giant Ionic Lattice A 3D structure of oppositely charged ions held together by strong electrostatic forces of attraction.
Giant Metallic Lattice A 3D structure of positive ions and delocalised electrons held together by metallic bonds.
Global Warming The increased average temperature of the planet and atmosphere, thought to be caused by increase concentrations of Carbon Dioxide.
Group A vertical column in the periodic table. Elements have similar chemical properties and their atoms have the same number of electrons in the outer shell.
Halogenation An addition reaction where a halogen is added across the C=C.
Haloalkanes A group of chemical compounds derived from alkanes, containing halogens.
Hess' Law States that the enthalpy change in a chemical reaction is independent of the route it takes.
Heterogeneous Catalyst A catalyst which is in a different phase from the reactant.
Heterolytic Fission Happens when each bonding atom receives one electron from the bonded pair to form 2 radicals.
Homogeneous Catalyst A catalyst which is in the same phase as the reactant.
Homologous Series A series of organic compounds that have the same functional group with successive members differing by a CH2.
Homolytic Fission Happens when one bonding atom receives both electrons from the bonding pair.
Hydrated A crystalline compound containing water molecules.
Hydration/Hydrolysis A reaction where water is a reactant.
Hydrocarbons Compounds that contain only carbon and hydrogen atoms.
Hydrogen Bond A strong permanent dipole-dipole attraction between an electron deficient H atom and a lone pair of electrons on O, N or F.
Hydrogenation An addition reaction where hydrogen is added across the C=C.
Hypothesis A prediction and explanation of the chemistry behind the prediction.
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