Shell Chemistry Summer Exam Revision Flashcards

Flashcards covering key vocabulary from Shell Chemistry Summer Exam Revision Guide.

Atom

The tiny particles that make up all matter.

Atomic Number

The number of protons in an atom.

Mass Number

The number of protons + number of neutrons in an atom.

Isotopes

Atoms of the same element with the same number of protons, but a different number of neutrons.

Relative Atomic Mass (Ar)

The average mass of the isotopes of the element relative to the mass of 1/12th of a 12C atom.

Element

Substance made up of just one type of atom e.g. carbon (C), hydrogen (H2), iron (Fe)

Compound

Substance made up of two or more types of atom chemically bonded together in fixed proportions e.g. carbon dioxide (CO2), water (H2O), calcium chloride (CaCl2)

Mixture

A number of elements and/or compounds mixed but not chemically joined, e.g. air, sea water, crude oil.

Relative Formula Mass (Mr)

The mass of a compound or molecule compared to carbon-12.

Exothermic Reaction

A chemical reaction in which heat energy is released and temperature increases.

Endothermic Reaction

A chemical reaction in which heat energy is taken in and temperature decreases.

State Symbols

Symbols used in chemical equations to show the state of substances: (s) solid, (l) liquid, (g) gas, (aq) aqueous.

Ions

Charged atoms formed by the loss or gain of electrons.

Metal Atoms

Tend to lose electrons to become positive ions (cations).

Non-metal Atoms

Tend to gain electrons to become negative ions (anions).

Ionic Bond

An electrostatic attraction between oppositely charged ions.

Combustion Reaction

Occurs when an element burns in oxygen.

Thermal Decomposition

Breaking down a substance by heating.

Acids

A source of hydrogen ions, H+.

Alkalis

A source of hydroxide ions, OH-.

Bases

Substances that can neutralise an acid, e.g., metal oxides, metal hydroxides and ammonia (NH3)

MASH

Metal + Acid -> Salt + Hydrogen

BAWS

Base (metal oxide) + Acid -> Water + Salt

AAWS

Alkali (metal hydroxide) + Acid -> Water + Salt

CAWSCoD

Metal Carbonate + Acid -> Water + Salt + Carbon Dioxide

Molecule

A group of atoms, which can be an element or compound e.g. H2 or H2O

Covalent Bond

An attraction between 2 nuclei and a shared pair of electrons

Diffusion

net movement of particles from an area of high concentration to an area of low concentration.

Solute

The solid that dissolves.

Solvent

The liquid the solid dissolves in.

Solution

The mixture formed when a solid dissolves in a liquid.

Saturated Solution

A solution which contains as much dissolved solid as possible at a particular temperature.

Solubility

The maximum amount of solute in grams that can dissolve in 100g of solvent at a certain temperature.

Hydrocarbon

A compound made up of hydrogen and carbon atoms only.

Homologous Series

A group of compounds that have the same general formula, similar chemical properties (and the same functional group) and a trend in physical properties.

Isomers

Molecules with the same molecular formula but a different displayed formula.

Alkanes

A homologous series that end in -ane.

Alkenes

A homologous series that end in -ene.

Saturated (referring to alkanes)

A molecule with no C=C double bonds.

Fuel

A substance that, when burned, releases heat energy.

Complete Combustion

Takes place when a fuel burns in a plentiful supply of oxygen, producing carbon dioxide and water only.

Incomplete Combustion

Takes place when a fuel burns in a limited supply of oxygen, producing carbon monoxide and water.