Chemistry definitions part 1

A few definitions for chemistry IGCSE's- more will be up soon!

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  • Created by: c1ats33
  • Created on: 14-05-13 15:10
Absolute Temperature
A temperature measured with respect to absolute zero on the Kelvin scale- absolute zero is the lowest possible temperature that can be achieved.
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Acid
A substance that dissolves in water, producing H+ ions- a solution of an acid turn litmus paper red and has a pH below 7; in their reactions act as proton donors.
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Acidic Oxides
Oxides of non-metals which will react with bases and dissolve in water to produce acid solutions.
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Alkali Metals
Elements in Group 1 of the Periodic Table; they are the most reactive group of metals
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Alkaline Earth Metals
Elements in Group 2 of the Periodic Table
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Alkalis
Soluble bases which produce OH- ions in water- a solution of an alkali turns litmus paper blue and has a pH above 7
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Alloy Steels
Steels in which iron is mixed with other transitions metals
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Alloys
Mixtures of elements designed to have the properties usefull for a particular purpose
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Amphoteric Hydroxides
Hydroxides which can react with both acids and alkalies to produce salts
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Antacid
A compound used to medically treat indigestion by neutralizing excess stomach acid
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Atom
The smallest particle of an element that can take part in a chemical reaction
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Atomic Number
The number of protons in the nucleus of an atom
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Balanced chemical equation
A summary of a chemical reaction using chemical formulae
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Base
A substance that neutralizes an acid- producing a salt and water as the only products
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Basic Oxide
Oxide of a metal that will react with acids to neutralize the acid
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Boiling
A condition under which gas bubbles are able to form within a liquid
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Boiling Point
The temperature at which a liquid boild, when the pressure of the gar created above the liquid, not just from its surface.
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Bond Energy
The energy required to break a particular type of covalent bond.
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Carbon Steel
Alloys of iron and carbon only; the amount of carbon in steels can vary between 0.2% and 1.5%
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Centrifugation
The separation of an insoluble solid from a liquid by rapid spinning
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Chemical Bonding
The strong forces that hold atoms or ions together in the various structures that chemical substances can form
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Chemical Reaction
A change in which a new substance is formed
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Chromatogram
The result of a paper chromatography run, showing where the spots of the samples have moved to.
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Chromatography
A technique employed for the separation of mixtures of dissolved substances, which was originally use to separate coloured dyes.
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Combustion
A chemical reaction in which a substance reacts with oxygen- the reaction is exo-thermic
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Compound
A substance formed by the chemical combination of two or more elements in fixed proportions
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Concentration
A measure of how much solute is dissolved in a solvent.
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Condensation
The change of a vapour or a gar into a liquid- during this process heat is given out the surroundings
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Covalment Bond
A chemical bond formed by the sharing of one of more pairs of electrons between two atoms
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Crystallisation
The process of forming crystals from a saturated solution
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Decating
The process of removing a liquid from a solid which has settled or from an immiscible heavier liquid by pouring.
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Density
Expresses the relationship between the masss of a substance and the volume it occupies
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Diatomic Molecule
A molecule containing two atoms
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Dibasic Acid
An acid which contains two replacable hydrogen atoms per molecule of the acid
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Diffusion
The process by which different fluid mix as a resultof the random motions of their particles
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Distillate
The liquid distilling over during distillation
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Distillation
The process of boiling a liquid and then condensing the vapour produced back into a liquid
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Downward delivery
A method of collecting a gas which is denser than air by passing it downwards into a gas jar
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Ductile
A word used to describe the property that metals can be drawn out and streched into wires.
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Electical Conductor
A substance that conducts electricity but is not chemically changed in the process
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Electron
A subatomic particle with negligible mass and a charge of -1
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Electron Arrangment
A shorthand method of describing the arrangement of electrons within the energy levels of an atom
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Electrostatic force of attraction
A strong force of attraction between particles with opposite charges-
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Element
A substance which cannot be further divided into simpler substances by chemical methods
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Endothermic change
A process or chemical reaction which takes in heat form the surroundings
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Energy levels of electrons
The allowed energies of electrons in atoms
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Evaporation
A process occuring at the surface of a liquid, involving the change of state from a liquid into a vapour at a temperature below the boiling point.
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Formula (chemical)
A shorthand method of representing chemical elements and compounds using the symbols of the elements
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Fractional distillation
A method of distillation using a fractionating column, used to separate liquid with different boiling points.
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Fractionating column
The vertical column which is used to bring about the separation of liquids in fractiona distillation
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Fractions (from distillation)
The different mixtures that distil over different temperatures during fractional distillation.
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Giant ionic structure
A lattice held together by the electrostatic forces of attraction between positive and negative ions
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Giant metallic lattice
A regular arrangement of positive metal ions held together by the mobile sea of electrons moving between the ions
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Giant molecular structure
Substance where large numbers of atoms are joined together by covalent bonds forming a strong lattice structure
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Group
A vertical column of the Periodic Table containing elements with similar properties
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Halides
Compounds formed between an element and a halogen
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Halogens
Element in group VII of the Periodic Table- generally the most reactive group of non-metals
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Immiscible
If two liquids from two layers when they are mixed together, they are said to be immiscible
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Indicator
A substance which changes colour when added to acidic or alkaline solutions
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Insoluble
Term that describes a substance that does not dissolve in a particular solvent
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Insulator
Substance that does not conduct electricity
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Intermolecular forces
The weak attractive forces which act between molecules
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Ionic bond
A strong electrostatic force of attraction between oppositely charged ions
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Ions
Charged particles made from an atom or group of atoms
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Lattice
A regular three-dimensional arrangement of atoms, molecules or ions in a crystalline solid
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Limewater
A solution of calcium hydroxide in water- the test from carbon dioxide gas
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Litmus
The most common indicator- turns red in acid and blue in alkali
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Locating agent
A compound that reacts with invisible, colourless spots separated by chromatography to produce a coloured product which can be seen
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Main- group element
The elements in the outer groups of the Periodic Table
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Malleable
A word used to describe the property that metals can be bent and beaten into sheets
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Mass concentration
The measure of the concentration of a solution in terms of the mass of the solute in grams
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Mass number
The total number of protons and neutrons present in the nucleus of an atoms
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Melting Point
The temperature at which a solid turns into a liquid
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Metallic Bond
An electrostatic force of attraction between the mobile sea of electrons and the regular array of positive metal ions whichin a solid metal
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Metals
A class of chemical elements which have a characteristic shiny appearance and are good conductors of heat and electricity
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Metalloid
An element that has properties of both a metal and a non-metal
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Microbe
A microscopic living organism, such as a bacterium or virus
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Minerals
Compounds that occur naturally in the Earth
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Mixture
Contains two or more substances that are not chemically combined
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Molar Solution
Contains one mole of a substance in 1dm cubed of water
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Molecule
A unit of two or more atoms
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Monatomic
Made up of single atoms
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Monomers
Small molecules that join together to form polymers
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Negative electrode
Another name for the cathode in an electrolysis cell
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Negative ion
An ion with a negative charge
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Neutralisation
The chemical reaction between an acid and a base or a carbonate, giving a salt and water
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Non-metal
An element that does not show metallic properties
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Nucleon number
The number of protons plus neutrons in an atom of an element
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Oxidation state
Every atom in a formula can be given a number that describes its oxidation state
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Paper chromatography
A way to separate the substances in a mixture, using a solvent and special paper, the substances separate because they travel over the paper at different speeds
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Percentage composition
Tells you which elements are in a compound, and what % of each is present by mass
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Photochemical reaction
A reaction that depends on light energy
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Polymerisation
A chemical reaction in which many small molecules join to form very large molecules
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Precipitate
An insoluble chemical produced during a chemical reaction
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Precipitation reaction
A reaction in which a precipitate forms
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Pure
There is only one substance in it
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Random motion
The zig-zag path a particle follows as it collides with other particles and bounces away again
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Redox reaction
Any reaction in which electrons are transferred
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Residue
The solid you obtain when you separate a solid from a liquid by filtering
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Reversible reaction
A reaction that can go both ways, a product can form, then break down again
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Saturated compound
An organic compound in which all the bonds between carbon atoms are single covalent bonds
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Solubility
The amount of solute that will dissolve in 100 grams of a solvent, at a given temperature
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Soluble
Will dissolve in a solvent
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Solute
The substance you dissolve in the solvent, to make a solution
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Solution
A mixture obtained when a solute is dissolved in a solvent
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Solvent
The liquid in which a solvent is dissolved to make a solution
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Thermal decomposition
The breaking down of a compound by heating it
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Yield
The actual amount of a product obtained in a reaction: it is often given as a percentage of the theoretical yield
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Other cards in this set

Card 2

Front

A substance that dissolves in water, producing H+ ions- a solution of an acid turn litmus paper red and has a pH below 7; in their reactions act as proton donors.

Back

Acid

Card 3

Front

Oxides of non-metals which will react with bases and dissolve in water to produce acid solutions.

Back

Preview of the back of card 3

Card 4

Front

Elements in Group 1 of the Periodic Table; they are the most reactive group of metals

Back

Preview of the back of card 4

Card 5

Front

Elements in Group 2 of the Periodic Table

Back

Preview of the back of card 5
View more cards

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