Basic chemistry definitions pdf

This is a simplified equation for a reaction involving ionic substances in which only those ions that actually take part in the reaction are shown.

This is a reaction which is catalysed by light or needs light in order to occur. The process where plants use sunlight to produce glucose and oxygen from carbon dioxide and water in the presence of chlorophyll.

A reaction in which the reactants combine to form products and the products can also react together to form the original reactants. Ions that are present in a chemical equation but do not take part in the overall reaction and do not change their physical or chemical status. This is the water that is stoichiometrically included in the structure of some salts during the crystallisation process.

Water of crystallisation is indicated with a dot written in between the salt molecule and the surrounding water molecules. An oxide that reacts with a base to form a salt and water. When dissolved in water it forms a solution with a low pH. An oxide that reacts with both acids and bases to form a salt and water.

A substance that neutralises an acid, producing a salt and water as the only products; in their reactions, bases act as proton acceptors. An oxide that reacts with an acid to form a salt and water.

When dissolved in water it forms a solution with a high pH. A type of chemical reaction where a compound breaks down into simpler substances.

When molecules, usually ionic, split up into smaller particles or ions in aqueous solution. This is usually a reversible process and the particles can recombine under different conditions.

A test for a particular metal cation by heating the sample of a compound in a blue Bunsen flame. Characteristic colours are produced indicating the identity of the metal in the compound. A substance which changes colour when added to acidic or alkaline solutions; for example, litmus or phenolphthalein. A reaction in which a solid product is formed when two solutions are mixed together. A reaction in which a more reactive element displaces a less reactive element from a solution of its salt.

A shorthand method of describing the arrangement of electrons within the energy levels of an atom; also referred to as electronic structure. Strong forces of attraction between particles with opposite charges — such forces are involved in ionic bonding. Vertical columns of the Periodic Table containing elements with similar properties; atoms of elements in the same Group have the same number of electrons in their outer energy levels.

Halide refers to the compound formed when a halogen combines with another atom, such as a metal. A halide ion is the negatively charged ion formed when a halogen atom accepts an electron. An inert substance does not react chemically with any other substance. Element which shows some of the properties of metals and some of non-metals; for example, boron and silicon.

A number given to show whether an element has been oxidised or reduced; the oxidation state of an ion is simply the charge on the ion. A table of elements arranged in order of increasing proton number atomic number to show the similarities of the chemical elements with related electron configurations.

The direct change of state from solid to gas or gas to solid: the liquid phase is bypassed. Elements from the central region of the Periodic Table — they are hard, strong, dense metals that form compounds that are often coloured.

They are also able to have more than one oxidation state. The protection of iron and steel objects by coating with a layer of zinc. An order of reactivity, giving the most reactive metal first, based on results from a range of experiments involving metals reacting with oxygen, water, dilute hydrochloric acid and metal salt solutions. The breakdown of a compound due to heating, where two or more products are formed. The stability of a molecule at high temperatures.

A molecule with high thermal stability is resistant at high temperatures and does not decompose. A substance is anhydrous when it contains absolutely no water. Petrol, diesel, oil or other fuel engines where the fuel is combusted inside the engine, the resulting explosive force being used to drive the engine pistons and generate motive power.

The industrial process of making sulphuric acid using a vanadium V oxide catalyst and high temperature.

An acid that contains two replaceable hydrogen atoms per molecule of the acid; for example, sulfuric acid, H 2 SO 4. A reaction in which a simple molecule adds across the carbon—carbon double bond of an alkene. Amide link or peptide link. The link between monomers in a protein or nylon, formed by a condensation reaction between a carboxylic acid group on one monomer and an amine group on the next monomer. Naturally occurring organic compounds which possess both an amino —NH 2 group and an acid —COOH group in the molecule; there are 20 naturally occurring amino acids and they are polymerised in cells to make proteins.

Branching occurs in an organic molecule when the longest chain is nonlinear as branches with groups of atoms or smaller chains sprout from the main chain.

General name given for simple and complex sugars having the general formula C x H 2 O y. Disrupt the characteristic properties of a protein or other biological molecule by excess heat, acidity, or pressure. The link produced when an ester is formed from a carboxylic acid and an alcohol; also found in polyesters and in the esters present in fats and vegetable oils.

A group of molecules with a defined boiling point range which distils off at the same place during fractional distillation. The atom or group of atoms responsible for the characteristic reactions of an organic compound.

A series of small differences or changes in characteristics or a specific property. Large number of hydrocarbon molecules. More viscous and less flammable so less useful. A small molecule, such as ethene, which can be polymerised to make a polymer. A polymer where the monomer units are joined together by amide peptide links; for example, nylon and proteins. A polymer where the monomer units are joined together by ester links; for example, Terylene. A substance consisting of very large molecules made by polymerising a large number of repeating units or monomers.

The chemical reaction in which molecules monomers join together to form a long-chain polymer. Condensation polymers formed from amino acids which are joined by peptide amide groups. Refers to the t echnique involving the condensation of vapors and the return of this condensate to the reaction system, usually in the same vessel. A compound containing only carbon-carbon single bonds with no carbon-carbon double or triple bonds. S mall numbers of hydrocarbon molecules which are more useful. Compounds that contain one or more carbon-carbon double or triple bonds.

The viscosity of a liquid is a description of its resistance to flow. A viscous liquid like honey for example flows much more slowly than a non-viscous liquid like ethanol. Test yourself with our topic questions. After studying the subject at university he went on to become a fully fledged Chemistry teacher, and now works in an international school in Madrid!

In his spare time he helps create our fantastic resources to help you ace your exams. Boiling point The temperature at which a liquid boils, when the pressure of the gas created above the liquid equals atmospheric pressure. Intermolecular forces The weak attractive forces which act between molecules. Melting point The temperature at which a solid turns into a liquid and which has the same value as the freezing point. Relative molecular mass M r The sum of all the relative atomic masses of the atoms present in a molecule.

Capillary action Capillary action is the ascension or movement of liquids through a slim tube, cylinder or permeable substance such as chromatography paper, due to adhesive and cohesive forces interacting between the liquid and the surface.

Centrifugation The separation of an insoluble solid from a liquid by rapid spinning during which the solid collects at the bottom of the sample tubes — the liquid can then be decanted off carefully. Condenser This is the part of the distillation apparatus that removes heat from the system by continual pumping of cold water.

Immiscible Two or more liquids which do not mix together are immiscible. Locating agent A compound that reacts with invisible, colourless spots separated by chromatography to produce a coloured product which can be seen. Miscible If two liquids form a completely uniform mixture when added together, they are said to be miscible. Allotropes Different atomic or molecular arrangements of the same element in the same physical state. Atomic number or proton number Z The number of protons in the nucleus of an atom; it is also the number of electrons present in an atom and determines the position of the element in the Periodic Table.

Metallic Lattice Giant three-dimensional lattice structure of positive ions surrounded by a sea of delocalised electrons. Nucleon number mass number A The total number of protons and neutrons in the nucleus of an atom. Polarity Polarity refers to the distribution of electrons in a bond or molecule. Relative atomic mass A r The average mass of naturally occurring atoms of an element on a scale where the carbon 12 atom has a mass of exactly 12 units.

Ionic equation This is an equation which shows only those ions and molecules that take part in the reaction. Spectator ion This is an ion which is present in a reaction mixture but which does not take part in the reaction.

Binary compound A compound consisting of only 2 elements e. Cryolite This is the compound sodium aluminium fluoride Na 3 A l F 6 which is a naturally occurring mineral found mainly in Greenland. Bond energy This is the energy required to break one mole of covalent bonds between two particular atoms and is measured in kJ per mole. Calorimetry The measurement of heat transfers in chemical reactions. Enthalpy This is the total amount of heat energy that a chemical system contains and considers both reactants and products.

Heat of combustion The heat change which takes place when one mole of a substance is completely burnt in oxygen. Activation energy This is the minimum energy required for particles to react when they collide.

Anhydrous salts Anhydrous means when a substance does not contain any water. Catalyst A substance that speeds up a chemical reaction without being used up or chemically altered in the reaction. Enzyme Enzymes are biological catalysts, usually proteins.

Equilibrium position The equilibrium position describes the relative concentrations of reactants and products at equilibrium. Hydrated salt Hydrated means when there is water present in a substance. Ionic equation This is a simplified equation for a reaction involving ionic substances in which only those ions that actually take part in the reaction are shown.

Photochemical reaction This is a reaction which is catalysed by light or needs light in order to occur. Photosynthesis The process where plants use sunlight to produce glucose and oxygen from carbon dioxide and water in the presence of chlorophyll. Reversible reaction A reaction in which the reactants combine to form products and the products can also react together to form the original reactants.

Spectator ions Ions that are present in a chemical equation but do not take part in the overall reaction and do not change their physical or chemical status.

Water of crystallisation This is the water that is stoichiometrically included in the structure of some salts during the crystallisation process. Acidic oxide An oxide that reacts with a base to form a salt and water. Amphoteric oxide An oxide that reacts with both acids and bases to form a salt and water. Base Alkali A substance that neutralises an acid, producing a salt and water as the only products; in their reactions, bases act as proton acceptors.

This is a collection of chemistry worksheets in pdf format. The answers to the questions are available on separate worksheets so you can fill them out and then check your work. Please feel free to download these to your computer, print them, and use them as hand-outs. Here are some printable periodic tables to help you out, also in pdf format. This is a flow chart of the steps of the scientific method, available as a PDF file:. Also available is a PDF of a pie chart of the elemental composition of the human body.

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