Chemistry AQA AS Flashcards
Key facts revision
0
Q
Absolute zero
A
The lowest possible temperature theoretically achieveable -273.15 degrees celius or zero Kelvin
1
Q
Absolute temperature
A
Temperature measured in Kelvin
2
Q
Acceleration
A
The stage in mass spectrometry where positive ions are speeded up by an electric field
3
Q
Acid rain
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Rain that has been acidified by pollutants such as sulfur dioxide
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Q
Actual yield
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Mass of product obtained in a reaction
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Q
Addition polymer
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Polymer formed when many small unsaturated molecules join together
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Q
Addition reaction
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The adding together of two or more more to form one larger molecule
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Q
Aldehyde
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An organic compound containing the -CHO functional group
8
Q
Alkaline earth metal
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An element from group 2 of the periodic table
9
Q
Alkane
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A saturated hydrocarbon with the general molecular formula CnH2n
10
Q
Allotrope
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Allotropes are different forms of the same element that exist in the same physical state. Diamond and graphite are allotropes of carbon
11
Q
Alloy
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A mixture of two or more metals or a mixture of metal and a non metal
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Q
Alpha particle
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A particle consisting of two protons and two neutrons ejected from a nucleus
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Q
Amine
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An organic compound that contains nitrogen atom joined to one or more carbon atoms and two or less hydrogen atoms
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Q
Amount of substance
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The number of particles present, symbol n. It is measured in mole, mol
15
Q
Anion
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A negatively charged ion attracted to the anode during electrolysis
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Q
Antacid
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A base taken as a medicine to neutralise excess stomach acid
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Aromatic
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Containing one or more benzene rings
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Atom
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The smallest particle of an element that has the properties of that element
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Atom economy
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The proportion of reactants that are converted into useful products rather than waste products
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Atomic number
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The number of protons in the nucleus of an atom, symbol Z
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Q
Atomic radius
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The distance from the centre of the nucleus to the outer electrons of an atom
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Q
Aufbau principle
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The building up process that describes the filling of atomic orbitals in order of increasing energy
23
Q
Avogadro constant
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The number of particles in one mole of a substance- 6.022*10^23
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Avogadro's principle
The idea that equal volumes of gases contain the same number of molecules under the same conditions of temperature and pressure
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Axial atom
Atom positioned at the top or bottom of a trigonal bipyramidal molecule
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Barometer
An instrument for measuring atmospheric pressure
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Base peak
The tallest peak in a mass spectrum
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Batch process
An industrial process that is started and stopped at intervals. Production of ethanol by fermentation is a batch process
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Bent line
The shape of a molecule that contains two bonding pairs and two lone pairs of electrons
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Biofuel
A fuel made from the products of living things
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Bond angle
The angle between two adjacent bonds on the same atom
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Bond
Attractive force between two atoms, ions or molecules
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Boyle's law
The volume of a fixed mass of gas (at a constant temperature) is inversely proportional to its pressure
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Burette
Labatory apparatus used to add precise volumes of liquid during a titration
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Carbocation
Ion with a positively charged carbon atom
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Carbonyl
An organic compound containing the -C+O functional group, found in baldheads and ketones
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Carboxyl
An organic compound containing the _COOH functional group
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Carboxylic acid
Organic acids with the general formula RCOOH. Their names end in -oic acid
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Cation
A positively charged ion, attracted to the cathodde during electrolysis
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CFC
Abbreviation for chloroflurocarbon, a hydrocarbon in which some or all the hydrogen atoms are replaced by chlorine and fluorine atoms
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Chain isomerism
A type of structural isomerism in which compounds have identical molecular formulae but their carbon atoms are joined together in different arrangments. Chain isomers involve branched and unbranched carbon chains
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Charge density
The charge: size ratio of an ion. Small ions with high charges have large charge densities
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Charle's law
The volume of a fixed mass of gas (at constant pressure) is proportional to its aboslute temperature
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Coke
Solid produced by heating coal in the absence of air, almost pure carbon
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Complete combustion
Burning a fuel in excess oxygen. Carbon dioxide and water vapour are produced from the complete combustion of hydrocarbons
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Concordant results
Titres that are in agreement usually within 0.10cm3 of each other
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Continous process
An industrial process in which products are made all the time without any break. Production of iron in the blast furnace is a continuous process
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Co-ordinate bond
A covalent bond in which the shared pair of electrons is provided by only one of the bonded atoms. In the bond X_>Y, X provides both electrons
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Covalent bond
A shared pair of electrons
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Cracking
A process used by the petroleum industry to produce shorter alkanes and alkenes from longer alkanes
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Cyclic
Hydrocarbons in which there are closed rings of carbon atoms are described as cyclic
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D block
The central section of the periodic table between groups 2 and 3 containing the transition metals
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Dative covalent bond
Another name for a coordinate bond
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Decomposition reaction
A reaction where one substance is broken down into two or more different substances
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Deflection
The stage in mass spectrometry where positive ions are moved from their original path by a magnetic field
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Dehydration reaction
A reaction where elements hydrogen and oxygen are removed from a reactant in the ratio of 2:1 effectively the removal of water
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Delocalized
Electrons that are free to move between all atoms in a structure are delocalized. Delocalized electrons are found in metals and graphite
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Detection
The stage in mass spectrometry where positive ions reach a detector and produce an electrical signal
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Diastereoisomers
Stereoisomers that are mirror images of each other, sometimes called geometrical isomers
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Diatomic
A molcule containing just two atoms
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Dimer
A molecule consisting of two monomer molecules joined together
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Dipole
Opposite charges separated by a short distance in a molecule or ion
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Displace
To replace an atom or ion in a compound in a chemical reaction eg chlorine displaces iodine in sodium iodide
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Displayed formula
A chemical formula showing all the atoms in a compound and their bonds
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Disproportionate
The simultaneous oxidation and reduction of a species
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Dot and cross diagram
A diagram showing all of the bonding electrons in a molecule. The electrons in one atom are shown as dots and the electrons in the other atom are shown as crosses
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Double covalent bond
A bond in which two atoms are joined by two shared pairs of electrons
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Ductile
Easily pulled into a thin wire
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Electrolysis
The decomposition of a compound into simpler substances using an electric current
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Electron gun
The source of high- energy electrons used to ionize the sample in mass spectrometry
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Electron-deficient
An atom with a vacant orbital
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electro negativity
The power of an atom to withdraw electron density from a covalent bond
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Electrophile
A species that can accept a pair of electrons
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Electrophilic addition
A reaction in which an electrophile is attracted to a region of high electron density such as a carbon-carbon double bond and adds on to an atom or group
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Electrostatic
Involving opposite charges
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Elimination reaction
A reaction in which a small simple molecule is removed from a compound forming a double covalent bond.
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Empirical formula
A formula that gives the simplest whole number ratio of atoms of each element in a compound
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Endothermic
A reaction in which heat energy is absorbed from the surroundings
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Endpoint
Where the indicator just changes colour in a titration
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Energy level
A certain fixed amount of energy that electrons in an atom can have also called a shell
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Equatorial atom
Atom positioned around the middle of a trigonal bipyramidal molecule
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Equivalence point
In an acid-base titration the point where equal numbers of moles of hydrogen ions and hydroxide ions have reacted
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Excess
More than the amount of reactant needed in a reaction
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Feedstock
Raw material used in a manufacturing process
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Fermentation
the process for making ethanol from sugar using yeast
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Fingerprint region
The part of an infrared spectrum that is unique to a particular compound
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First ionization energy
The energy needed to remove one mole of electrons from one mole of gaseous atoms forming one mole of ions with a single positive charge
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Flue gas desulfurization
Removing sulfur compounds from waste gases produced by combustion
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Flue gas
Waste gases from the combustion of a fuel for example in a power station
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Fraction
A part of a mixture collected at a particular temperature range by fractional distillation. A crude oil fraction contains hydrocarbons with a similar chain length
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Fractional distillation
A method of separating mixtures of liquids or gases according to their boiling temperatures
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Free radical
A species that contains an unpaired electron produced by homolytic fission of a covalent bond
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Frequency
The number of waves per second measured in hertz, Hz
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Functional group
An atom, or group of atoms in a molecule which determines its chemical properties
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Gas constant
The constant used in the ideal gas equation. Symbol R and is approximately 8.31JK^-1mol^-1
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Giant covalent
A structure in which very many atoms are joined by covalent bonds to form a regular structure. Diamond and graphite have giant covalent structures
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Greenhouse effect
Absorption of thermal energy by certain gases in the atmosphere keeping the planet warmer than it would be otherwise
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Greenhouse gas
An atmospheric gas that traps infrared raiation that would otherwise be radiated from the earth's surface into space
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Halide ion
A negatively charged ion formed when a halogen atom gains an electron
100
High resolution mass spectroemter
Device capable of measuring relative atomic masses and relative molecular masses to a high degree of precision
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Homologous series
A series od compounds with the same general formula and functional group. Each member differs from the next by the presence of one more -CH2 group
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Homolytic fission
Breaking of a covalent bond so that each atom takes one electron from the shared pair becoming a radical
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Hund's rule
Only when all the orbitals in a particular sub level contain an electron do electrons begin to ccupy the orbitals in pairs
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Hydration
The addition of water across a double bond
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Hydrocarbon
A compound containing hydrogen and carbon atoms only
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Hydrogen bond
An intermolecular force between a lone pair of electrons on an N, O or F atom in one molecule and an H atom joined to an N, O or F atom in another molecule
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Hydrolysis
The splitting of a compound by reaction with water
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Hydroxyl group
An -OH group, the functional group found in alcohols
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Ideal gas equation
The equation that describes the relationship between pressure, volume, amount of substance and absolute temperature of a gas pV=nRT
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Incomplete combustion
Burning of a fuel in a restricted amount of oxygen
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Indicator
A substance that changes colour according to the pH of a solution
112
Induced dipole
An uneven distribution of charge in a molecule or atom caused by a charge in an adjacent particle
113
Infrared radiation
Electromagnetic radiation with a lower frequency than visible light, felt as heat
114
Infrared absorption spectrum
Spectrum produced when infrared radiation of various frequencies is absorbed by covalent bonds in a molecule
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Infrared spectroscopy
Method used to analyze compounds by their absorption of infrared radiation
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Initiation
The first stage in a free radical reaction
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Intermediate
Unstable species produced during a reaction before the final product is made
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Intermolecular force
Weak attractive force between molecules
119
Ionic bond
Electrostatic force of attraction between oppositely charged ions
120
Ionic radius
The distance from the centre of the nucleus to the outer electrons of an ion
121
Ionization
Producing an electrically charged particle by adding or removing electrons from an atom or molecule
122
Ionized
An atom or molecule that has gained or lost electrons is said to be ionized
123
Isoelectronic
Having the same electrong formula but different structural formulae
124
Kelvin
The unit of absolute temperature symbol K
125
Ketone
An organic compound containing the carbonyl functional group -C=O and with the general formula R1COR2
126
Lattice
A regular arrangement of atoms, ions or molecules in a structure
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Limiting reactant
A reactant that is completely used up before the other reactants are converted into products
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Linear molecule
A molecule with all of its atoms in a straight line
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Lone pair
A pair of electrons in the highest occupied energy level that are not used in bonding
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Malleable
Can be bent or hammered into shape without breaking
131
Mass spectrometer
An instrument used to determine the relative atomic mass of an element or relative molecular mass of a compound. The structure of a complex molecule can be worked out by analysis of a mass spectrum
132
Mass spectrum
The output from a mass spectrometer plotting relative abundance against mass to charge ratio m/z
133
Mass to charge ratio
The mass of an ion divided by its charge symbol m/z
134
Metallic bond
The electrostatic force of attraction between metal ions and the delocalized electrons in a metallic lattice
135
Metalloid
Element with properties that are intermediate between the properties of a metal and the properties of a non metal
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Molar volume
The volume occupied by one mole of gas at a specified temperature and pressure
137
Molarity
The concentration of a solution measured in moles of solvent per cubic decimetre of solution mol dm^-3
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Molecular crystal
Covalent molecules held together in a regular arrangement by intermolecular forces
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Molecular ion
In mass spectrometry the ion that produces a peak in a mass spectrum at the highest m/z value
140
Molecular sieve
Porous materials such as zeolites that let some molecules pass through but not others
141
Monoprotic
An acid containing one replaceable hydrogen ion such as Hcl and HNO3
142
Nitrile
An organic compound containing the -C=-tripleN functional group
143
Non polar
Having no dipole. A molecule with polar bonds may be non polar if its shape is such that the dipoles cancel each other out
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Nucleophile
A species with a lone pair of electron that is available to form a coordinate bond
145
Nucleophilic substitution
A chemical reaction in which one nucleophile replaces another in a molecule
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Orbital
The volume of space in an atom where one or two electrons are most likely to be found
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Ore
A mineral from which metals can be extracted and purified
148
Ozone
An allotrope of oxygen with the formula 03
149
Ozone layer
The part of the atmosphere with the greatest concentration of ozone. Found in the stratosphere it absorbs harmful ultraviolet radiation from the sun
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Pauli exclusion principle
The idea that an orbital cannot hold more than two electrons
151
Pauling electro negativity scale
A scale showing the ability of elements to withdraw electron density from a covalent bond. The larger the number the more electronegative the element
152
Permanent dipole-dipole forces
Attractive forces that exist between polar molecules
153
Polar bond
A covalent bond between atoms with different electro negativities
154
Polarized
Having opposite charges separated by a small distance
155
Polyatomic ion
An ion containing more than one atom
156
positional isomerism
A type of isomerism where the functional group can be joined at different places on the carbon skeleton
157
Precipitate
An insoluable solid formed when two solutions are mixed
158
Primary haloalkane
An haloalkane with one carbon atom or where the carbon atom carrying the halogen atom is directly attached to just one other carbon atom
159
Propagation
The stage in a free radical mechanism where a particular radical is used in one reaction then produced again in a subsequent reaction
160
Reaction mechanism
A step by step description of how a reaction happens
161
Roast
Heating strongly in a steam of air usually apllied to metal ores
162
Saturated
A compound containing only single covalent bonds between carbon atoms
163
Semiconductor
A substance that is an electrical insulator at room temperature but a conductor when warmed or when other elements are added to it
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Solute
The substance that will dissolve in a solvent
165
Solvent
The substance in which a solute will dissolve
166
Spectator ion
An ion that appears on both sides of an equation but does not take part in the reaction
167
Standard solution
A solution whose exact molarity is known
168
Standard temperature and pressure
273K and 100kPa
169
Stereoisomer
Moelcules with the same structural formula but a different arrangement of their bonds in space
170
Stratosphere
Upper part of the atmosphere
171
Structural isomerism
When two or more compounds have the same molecular formulae but different structures
172
Sub level
Part of an energy level in an atom containing pairs of electrons
S sub levels contain up to one electron pair
P sub levels contain up to three electron pairs
D sub levels contain up to five electron pairs
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Sublime
To pass directly from the solid state to the gas state
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Substitution
The replacement of one atom or group of atoms in a molecule by another atom or group of atoms
175
Temporary dipole
The asymmetrical distribution of the electron pair in a covalent bond
176
Termination
The final stage in a free radical substitution reaction
177
Theoretical yield
The maximum mass of product possible calculated using th emas sof reactants and the balanced equation
178
Thermal cracking
The thermal decomposition of hydrocarbons to produce shorter alkanes and alkenes
179
Titrant
The solution added from the burette in a titration
180
Titration
Method used to find the concentration of a sample using a reactant og known concentration
181
Titre
The volume of titrant added to reach the end point in a titration
182
Trigonal bipyramial
The shape of a molecule with 5 bonding pairs of electrons
183
Trigonal planar
The shape of a molecule with 3 bonding pairs of electrons
184
Trigonal pyramidal
The shape of a molecule with 3 bonding pairs and 1 lone pair of electrons
185
Unburned hydrocarbons
Pollutants in the exhaust from car engines due to incomplete combustion of the fuel
186
Unsaturated
Containing at least one carbon- carbon double bond
187
Valence shell
The energy level in an atom that is involved in forming bonds
188
Van der waals forces
Temporary induced dipole-dipole attractions between covalent moelcules
189
Volatile
A liquid that easily vaporizes is said to be very volatile
190
Volumetric flask
An item of glassware used to make up a standard solution. Also called a graduated/standard flask
191
VSEPR
Valence shell electron pair repulsion theory. The theory used to predict the shape of a covalent molecule using the idea of repulsion by pairs of electrons
192
Zeolite
Compound of aluminium, silicon and oxygen with microscopic pores. Zeolites are used as catalysts and molecular sieves in the petrochemical industry
