Matter and Materials Glossary

  • acid rain: rainwater that is unusually acidic as a result of dissolved non-metal oxides that have entered the atmosphere
  • acidity: this word is related to the word 'acid', so is the word 'acidic'; a substance is strongly acidic when it has a high (degree of) acidity
  • alternative: different
  • atomic number: a unique number that represents a given element, and shows its position on the periodic table; the number of protons found in the nucleus
  • balanced: a balanced equation reaction has the same numbers of atoms of a particular type on opposite sides of the reaction equation
  • barrier: a fence or other obstacle that keeps things apart
  • bond: a force between atoms in a compound, holding them together
  • camera flash: a device (usually attached to the camera) that provides a quick burst of light at the instant that the photo is taken
  • characteristic: a quality or feature of an object or item; for example, one of the characteristics of an acid is that it is corrosive
  • chemical bond: a special attractive force that holds the atoms in a molecule together
  • chemical equation: an equation that describes a chemical reaction using the chemical formulae of the compounds involved in the reaction
  • chemical formula: a combination of element symbols that shows the types and number of atoms in one molecule of a given compound; a unique string of symbols (letters and numbers) that represents a chemical compound
  • chemical reaction: a process in which atoms in substances, called reactants, are rearranged to form new substances, called products
  • chemist: a person who has studied chemistry and uses this knowledge to do his/her job
  • chromed metal: metal that is covered by a thin layer of chromium
  • coefficient: a number that is placed in front of a chemical formula in a reaction equation; it shows the number of molecules of that type taking part in the reaction, for example 2 Mg
  • collide: to bump into something
  • combustion: a type of chemical reaction where a substance and oxygen react during burning to form a new product
  • compound: a pure substance in which atoms of two or more different chemical elements are bonded in some fixed ratio
  • convention: a way in which something is usually done
  • corrosion: the gradual destruction of materials (usually metals) by chemical reaction with substances in the environment
  • corrosive: a corrosive substance is something that causes corrosion; substances that are corrosive can cause burns on the skin and damage to certain surfaces
  • crystal lattice: in some compounds, the atoms are arranged in a regular pattern in a fixed ratio to form a lattice structure; a lattice looks like a mesh or trellis
  • density: the mass of a substance in a given space (volume)
  • detour: to take a roundabout route, either to make a visit along the way, or to avoid something
  • diatomic: a diatomic molecule consists of two atoms; H2, N2, O2, F2, Cl2, Br2, and I2 are all examples of elements that consist of diatomic molecules
  • dioxide: a compound that contains two oxygen atoms in its chemical formula; examples are carbon dioxide (CO2) and sulfur dioxide (SO2)
  • electrons: the smallest of the three types of sub-atomic particles; they are negatively charged and are located outside the atomic nucleus
  • element: a pure substance that consists of only one type of atom throughout
  • exchange reaction: a reaction in which the reactants break up in fragments that are then exchanged, or swapped around
  • exposed: when a material is exposed, it is uncovered or unprotected (in this case from oxygen that will react with it)
  • fossil fuel: a fuel that was formed from the prehistoric remains of plant and animal life (fossils); it usually has to be extracted from the earth; examples include oil, coal and natural gas
  • fuel: a substance that will release energy when it reacts with another substance; in this context that other substance is usually oxygen
  • galvanise: to galvanise iron or steel means to cover it with a thin layer of zinc; the zinc reacts with oxygen to form zinc oxide when it is exposed to air and this forms a strong and impenetrable coating
  • galvanisedmetal: metal that is covered by thin layers of zinc and zinc oxide
  • generate: to produce something; in this case it refers to some other source of energy being converted to electrical energy (electrical power or electricity)
  • group: the vertical columns of the Periodic Table are called groups
  • identical: exactly the same in every way
  • ignite: to set something on fire
  • indicator: a substance that changes colour in the presence of another substance, showing that that substance is present
  • inert: unreactive; these substances do not react with other substances and do not change into other compounds
  • IUPAC system: a system for naming compounds in a way that is unique for each compound
  • IUPAC: International Union of Pure and Applied Chemistry (acronym)
  • laboratory acids: acid commonly found in the laboratory
  • litmus: a well known acid-base indicator that turns red when mixed with an acid and blue when mixed with a base
  • macroscopic: the macroscopic world includes all the things we can observe with our five senses - things we can see, hear, smell, touch and taste
  • metal carbonate: a compound with the the general formula MCO3 or M2CO3 where M represents a metal atom, C represents a carbon atom and O represents an oxygen atom
  • metal hydroxide: a compound with the the general formula MOH or M(OH)2 where M represents a metal atom, O represents an oxygen atom and H represents a hydrogen atom
  • metal oxide: the product of the reaction between a metal and oxygen; a compound with the general formula MO or M2O where M represents a metal atom and O represents an oxygen atom
  • metal: an element that is shiny, ductile and malleable; metals occur on the left and towards the middle of the periodic table
  • molecule: two or more atoms that have chemically bonded with each other; the atoms in a molecule can be of the same kind (in which case it would be a molecule of an element), or they can be of different kinds (in which case it would be a molecule of a compound)
  • neutral solution: a solution with pH = 7
  • neutralisation reaction: a reaction in which the reactants neutralise each other
  • neutralise: to neutralise something means to take away its potency
  • neutrons: a type of sub-atomic particle similar to protons in mass and size, but neutral (without charge); neutrons together with protons make up the atomic nucleus
  • non-metal oxide: the product of the reaction between a non-metal and oxygen
  • non-metal: an element that does not have metallic properties; non-metals (excluding hydrogen) occur in the top right-hand corner of the periodic table
  • non-renewable: non-renewable energy sources refer to sources that can be used up, such as fossil fuels (coal, oil, or natural gas)
  • oxidise: when a compound reacts with oxygen, we say it is oxidised; in chemistry, the word oxidise means much more than this, but in this chapter we will limit ourselves to this simple definition
  • penetrate: when liquid or air penetrates into a material, it passes into or through that material (usually because of tiny holes in the material); something that cannot be penetrated is called impenetrable
  • period: the horizontal rows of the Periodic Table are called periods
  • periodic table: a table in which the chemical elements are arranged in order of increasing atomic number
  • pH: pH measures the acidity and alkalinity of a solution as a number on a scale ranging between 0 and 14
  • pharmacist: a person who has studied pharmacy and uses this knowledge in the field of health science
  • picture equation: an equation that describes a chemical reaction using diagrams of the particles of the compounds involved in the reaction
  • porous: material that has tiny holes through which liquid or air may pass
  • potency: power
  • prefix: a bit added at the start of a word, usually to indicate number, e.g., mono-, di-, or tri-
  • presence: the state of something existing or being present in a place
  • preservative: a substance that is added to products (usually food or beverages) to make them last longer; most preservatives are toxic to microorganisms, but are added in such small quantities that they do not pose significant harm to humans
  • product: a substance that forms during the reaction; it will be present after the reaction has taken place
  • protons: sub-atomic particles that are positively charged and occur inside the atomic nucleus along with neutrons
  • reactant: the starting substances that undergo change in a chemical reaction
  • reactive: elements and compounds that are reactive will readily react with many other substances
  • red cabbage indicator: An acid-base indicator made from the sap of red cabbage; red cabbage indicator is also capable of displaying a range of colours, depending on the pH of the solution with which it is mixed
  • renewable: a renewable source of energy cannot be used up, such as water, wind, or solar power
  • rust-resistant: a rust-resistant material; one that does not rust
  • rust: a reddish- or yellowish-brown, often flaky, coating of iron oxide that is formed on iron or steel by oxidation (when it reacts with oxygen in the air)
  • semi-metal: an element that has properties of both metals and non-metals; the semi-metals occur in a narrow diagonal strip that separates the metals form the non-metals on the periodic table
  • steel: a metal alloy composed of a mixture of iron and other elements (mostly metal); it is very strong and used widely in the construction industry (also in buildings)
  • submicroscopic: the submicroscopic world includes things that exist but that we can't see; atoms and molecules can only be 'seen' as mental pictures and when we draw these, we refer to them as 'submicroscopic diagrams'
  • subscript: a number that is placed inside a chemical formula; it shows the number of atoms of that type in one molecule of that compound, for example O2
  • suffix: a bit added at the end of a word, e.g., -ide
  • symbol (or element symbol): a unique letter (or letters) that represent a given element
  • symbolic: the symbolic world includes letters and numbers that we use to represent atoms and molecules
  • systematic name: The unique name that will be generated for a given compound, if the IUPAC system for naming compounds is followed correctly
  • tarnish: when a metal surface gets dirty or spotty after reacting with oxygen or other substances in the air, we say it is tarnished
  • toxic: poisonous, harmful to living organisms
  • unique: the only one of its kind; unlike anything else
  • unit: In this chapter, unit means a quantity used as a standard of measurement, e.g. units of time are second, minute, hour, day, week, month, year and decade
  • universal indicator: An acid-base indicator that can display a range of colours, depending on the pH of the solution with which it is mixed
  • word equation: an equation that describes a chemical reaction using the names of the compounds involved in the reaction