Chemistry Definitions

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  • Created by: darcylizz
  • Created on: 10-05-17 15:34
What is Electronegativity?
Electronegativity is the power of an atom to attract the electrons in a covalent bond
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What is Empirical Formulae?
The empirical formula is the formula which represents the simplest ratio of atoms of each element in a compound
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What is the Molecular Formula?
The molecular formula gives the actual number of atoms of each element in a molecule.
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What is a Fraction?
A mixture of hydrocarbons with similar boiling points.
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What are Structural Isomers?
Structural isomers are compounds with the same molecular formula but different structural formulae. This Includes Functional Group, Chain and Positional Isomers
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What is Structural Formula?
The structural formula shows the unique arrangement of atoms in a molecule in a simplified form without showing all the bonds.
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What are Functional Group Isomers?
Functional Group Isomers have the same molecular formula but the functional group is different.
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What are Chain Isomers?
Chain isomers have the same molecular formula and same functional group but the arrangement of the carbon atoms in the chain is different.
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What are Positional Isomers?
Positional isomers are structural isomers that have the same carbon skeleton and same functional group, but the functional group is joined at different places on the carbon skeleton.
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What is a Homologous Series?
A family of organic compounds which all contain the same functional group, but have an increasing number of carbon atoms. Each member of a homologous series has the same general formula
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What is a First Ionisation Energy?
The energy required to remove one mole of electrons from one mole of gaseous atoms.
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What is Cracking?
Cracking is the breakdown of longer chain hydrocarbon molecules into smaller ore useful ones.
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What is Displayed Formula?
The formula that shows all the bonds present in a molecule.
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What is a Metalic Bond?
An electrostatic attraction between metal ions and delocalised electrons
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What is Relative Molecular/Formula Mass?
...
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What is a Polar Bond?
A covalent bond in which the pair of electrons are not equally shared.
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What is Periodicity?
Pattern in the change in properties of a row of elements repeated in the next row.
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What is a Biofuel?
Fuel produced from renewable plant material
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What is a Carbocation?
A species which contains a carbon atom that has a positive charge.
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What is the Fingerprint Region?
The region below 1500 cm-1 in an infra-red spectrum.
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What is Homolytic Fission?
Formation of radicals when a covalent bond breaks with an equal splitting of the bonding pair of electrons.
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What is a Free Radical?
A chemical species with an unpaired electron.
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What is an Electrophile?
An electron deficient species that accepts an electron pair.
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What is a Nucleophile?
An electron pair donor.
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What is a Stereoisomer?
Compounds that have the same molecular formula and structural formula but have different arrangements of their atoms in space.
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What is a Elimination Reaction?
A reaction in which an unsaturated compound is formed by the removal of a small molecule such as hydrogen bromide.
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What is Refluxing?
A process in which a reaction mixture is heated in a flask fitted with a condenser to prevent the loss of volatile substances, including the solvent.
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What is a Molecular Ion?
A species formed in a mass spectrometer by the loss of one electron from a molecule.
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What is Enthalpy Change?
Enthalpy change is the heat energy change measured under conditions of standard pressure.
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What is the Standard Enthalpy of Formation?
The standard enthalpy of formation is defined as the enthalpy change when 1 mole of a compound is produced from its elements under standard conditions, all reactants and products being in their standard states.
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What is the Standard Enthalpy of Combustion?
The standard enthalpy of combustion is defined as the enthalpy change when 1 mole of a substance is completely burned in oxygen under standard conditions, all reactants and products being in their standard states.
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What are the Standard Conditions?
100kPa pressure and 298K In ΔH O the O means standard conditions
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What is Hess's Law?
Hess’s law states that the enthalpy change in a reaction is independent of the route taken.
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What is the Mean Bond Enthalpy?
Mean bond enthalpy is the enthalpy required to break a covalent bond averaged over many compounds.
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What is Le Chatelier's principle?
Le Chatelier’s principle states that if one or more of the factors that affect the position of equilibrium is altered, then the equilibrium shifts to reduce the effect of the change.
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What is a Homogeneous Equilibria? and what is a Maxwell Boltzmann distribution curve?
Homogeneous equilibria is when all the reactants are in the same state (phase). A Maxwell Boltzman Distribution Curve shows the distribution of the energies of the molecules in a gas.
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What is a Dynamic Reaction?
A reaction which proceeds simultaneously in both directions
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What is Equilibria?
At equilibrium the rate of the forward reaction equals the rate of the backward reaction and so the concentration of the reactants and products are constant
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What is a Oxidation State?
The number of electrons lost or gained by an atom in a compound compared to the uncombined atom.
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What is a Closed System and a Rate of Reaction?
Closed system means that no more reactants are added and no products are removed. Rate of Reaction is the change in concentration of a substance per unit of time
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Other cards in this set

Card 2

Front

What is Empirical Formulae?

Back

The empirical formula is the formula which represents the simplest ratio of atoms of each element in a compound

Card 3

Front

What is the Molecular Formula?

Back

Preview of the front of card 3

Card 4

Front

What is a Fraction?

Back

Preview of the front of card 4

Card 5

Front

What are Structural Isomers?

Back

Preview of the front of card 5
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