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51 Cards in this Set
- Front
- Back
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Mass Number |
The number of protons plus neutrons in the nucleus of an atom of an element |
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Atomic number |
The number of protons in the nucleus of an atom |
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Relative atomic mass |
The average mass of an atom of an element relative to the mass of an atom of Carbon-12, whose mass is defined as exactly 12 |
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Avagadro's number |
6.02x10^23 |
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Empirical Formula |
Simplest whole number ratio of atoms of each element in a compound |
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Molecular Formula |
Formula showing the actual number of atoms of each element in one molecule of a compound or one formula unit |
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Structural formula |
Formula showing how the atoms of each element present in a molecule are bonded together |
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First ionisation energy |
The enthalpy change when 1 mole of electrons are removed from 1 mole of gaseous atoms to form 1 mole of unipositive ions |
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Ideal Gas Equation |
PV=nRT (define P,V,n,R,T & UNITS) |
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Covalent bond |
A shared PAIR of electrons |
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Coordinate/dative-covalent bond |
A covalent bond where both shared electrons came from one of the bonded atoms |
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Electronegativity |
The power of an atom to withdraw electron density FROM A COVALENT BOND |
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Homologous series |
A family of organic compounds that have similar chemical properties due to the presence of the same functional group |
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Functional group |
An atom or group of atoms which, when present in different molecules, causes them to have similar chemical properties |
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Saturated |
An organic compound which only contains single bonds |
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Hydrocarbon |
An organic compound which contains carbon and hydrogen only |
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Structural isomerism |
Molecules with the same molecular formula but with different structural formulae |
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(Carbon) chain isomerism |
Molecules with the same molecular formula but which have a different arrangement of the carbon chain |
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Position isomerism |
Molecule with the same molecular formula, same carbon skeleton and same functional group, but the functional group is attached to different places on the carbon skeleton |
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Functional group isomerism |
Same molecular formula but different functional group |
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Stereoisomerism |
Molecules with the same molecular AND structural formula but their bonds are arranged differently in space |
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Geometric/z-e isomerism |
Stereoisomerism arising from the presence of a C=C where there are two different groups attached at each end of the C=C |
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Nucleophile |
Electron PAIR donor |
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Electrophile |
Electron PAIR acceptor |
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Substitution |
The replacement of an atom or group of atoms by another atom or group of atoms |
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Cracking |
Long chain hydrocarbons broken into smaller chain hydrocarbons |
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Hydrolysis |
The breaking of covalent bonds by reaction with water |
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Hydration |
The ADDITION of water to a species |
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Addition Reaction |
When two molecules react together to form one |
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Molecular Ion |
A positive ion with the highest m/z value, formed by removal of one electron from the parent molecule |
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Free Radical |
A reactive species which contains an unpaired electron |
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Initiation Step |
One in which free radicals are generated |
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Propagation Step |
One in which the number of free radicals is maintained |
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Termination Step |
One in which free radicals react with each other and reduce the overall number of free radicals |
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Enthalpy Change |
Heat energy change at constant pressure |
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Standard Conditions |
All substances in their standard stable states, under conditions of 298K and 100kPa |
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Standard Enthalpy of Formation |
Enthalpy change for the formation of one mole of a substance from its constituent elements, with all reactants and products in their standard stable states, under conditions of 298K and 100kPa |
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Standard Enthalpy of Combustion |
Enthalpy change for the complete combustion of one mole of a substance in oxygen, with all reactants and products in their standard stable states, under conditions of 298K and 100kPa |
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Bond Dissociation Enthalpy |
The enthalpy change for the breaking of one mole of a specific covalent bond in the gas phase, averaged over a wide range of compounds in which the bond is found |
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Hess's Law |
The enthalpy change for a reaction is independent of the route taken, all measurements being made at the same temperature and pressure |
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Rate of Reaction |
The change in concentration of a reactant or product per unit time |
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Activation Energy |
The minimum amount of energy required for a reaction to occur on collision between reactant particles |
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Catalyst |
A substance which alters the rate of a reaction without being used up. Catalysts which speed up a reaction do so by providing an alternative reaction pathway with a lower activation energy |
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Dynamic Equilibrium |
A reversible reaction reaches dynamic equilibrium when the rate or the forward reaction equals the rate of the reverse reaction. The reaction is continuous, but the concentrations of the reactants and products remain constant (though seldom equal) |
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Le Chatelier's Principle |
A system at equilibrium will shift its equilibrium in such a direction as to oppose any change which is imposed upon it |
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Oxidation |
Loss of electrons, gain of oxygen, loss of hydrogen |
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Reduction |
Gain of electrons, loss of oxygen, gain of hydrogen |
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Oxidising agent |
An electron acceptor |
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Reducing agent |
An electron donor |
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Carbon Neutral
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An activity that has no net annual carbon (CO2/greenhouse gas) emissions to the atmosphere |
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Biofuel |
A fuel that is produced from plants or material derived from plants. Biofuels are renewable fuels |
