Flashcards in Key words/formulas and their points Deck (64)
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1
Acid
A species that is a proton donor
2
Activation energy
The minimum energy required to start a reaction by breaking bonds
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Addition reaction
A reaction in which a reactant is added to an unsaturated molecule to make a saturated molecule
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Alkali
A type of base that dissolves in water forming hydroxide ions
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Alkanes
CnH2n+2
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Anion
Negative ion
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Atom economy
atom economy = molecular mass of the desired product / sum of molecular masses of all products x100
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Orbital
A region within an atom that can hold up to two electrons with opposite spins
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Average bond enthalpy
The average enthalpy change that takes place when breaking by homolytic fission 1 mol of a given type of bond in the molecules of a gaseous specie
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Atomic number
Protons in nucleus
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Avogadros constant
Number of atoms per mole of a carbon - 12 isotope (6.02x1023)
12
Base
Proton acceptor
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Catalyst
A substance that increases rate of a chemical reaction without being used up
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Cation
Positively charged ion
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Cis isomerism
H atoms on same side
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Trans isomerism
H atoms in different sides
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Covalent bond
Shared pair of electrons
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Curley arrow
Show the movement of a pair of electrons
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Diative covalent bond
Shared pair of electrons provided by one bonding atom only
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Displacement reaction
Where a more reactive element replaces a less reactive element from an aqueous solution of latter's ions
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Dynamic equilibrium
-closed system
-forward reaction rate is equal to reverse reaction rate
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Electronegativity
A measure of attraction of a bonded atom for a pair of electrons in a covalent bond
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Sheilding
Repulsion of electrons from different inner shells
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Electrophile
An atom that us attracted to an electron rich centre or atom where it accepts a pair of electrons to form a new covalent bond
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Elimination reaction
Removal of a molecule from a saturated molecule to make an unsaturated molecule
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Empirical formula
Simplest whole-number ratio of atoms of each element present in a compound
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Endothermic
Enthalpy of products is greater than enthalpy of reactants resulting in heat being taken in from surroundings
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Standard enthalpy change of combustion
The enthalpy change that takes place when one mole of a substance reacts completely with oxygen under standard conditions, all reactants and products being in their standard states.
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Standard enthalpy change formation
The enthalpy change that takes place when one mole of a compound is formed from its constituent elements in their standard states under standard conditions.
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Standard enthalpy change of reaction
The enthalpy change that accompanies a reaction in the molar quantities expressed in a chemical equation under standard conditions, all reactants and products being in their standard states.
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Esterfication
Alcohol + carboxylic acid > ester + water
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Exothermic
Enthalpy of the products is smaller than the enthalpy of the reactants resulting in heat loss to surroundings
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Greenhouse effect
The process in which the absorption and subsequent emission of IR by atmospheric gasses warms the lower atmos and planets surface
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Group
-Vertical column
-similar chemical properties
-same number of outer electrons
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Hess's Law
If a reaction can take place by more than one route and the initial and final conditions are the same, the total enthalpy change is the same for each route.
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Heterolyric fission
The breaking of a covalent bond with both of the bonded electrons going to one of the atoms, forming a cation (+ ion) and an anion (– ion).
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Homolytic fission
The breaking of a covalent bond with one of the bonded electrons going to each atom, forming two radicals.
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Homologous series
A series of organic compounds with the same functional group, but with each successive member differing by CH2.
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Ionic bond
An electrostatic attraction between oppositely charged ions
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First ionisation energy
The energy required to remove one electron from each atom in one mole of gaseous atoms to form a gaseous 1+ ion
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le Chatelier's Principle
When a system in dynamic equilibrium is subjected to a change, the position of equilibrium will shift to minimise the change.
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Mass number
Protons and neutrons in the nucleus
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Metallic bonding
Electrostatic attraction between positive metal ions and delocalised electrons
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Mole
Amount of any substance containing as many particles as there are carbon atoms in exactly 12g of the carbon 12 isotope
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Nucleophile
An atom (or group of atoms) that is attracted to an electron- deficient centre or atom, where it donates a pair of electrons to form a new covalent bond.
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Nuclophilic substitution
A type of substitution reaction in which a nucleophile is attracted to an electron-deficient centre or atom, where it donates a pair of electrons to form a new covalent bond.
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Percentage yield
% yield = actual amount, in mol, of product/ theoretical amount, in mol, of product x100
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Period
-horizontal row of elements
-trends in properties
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Periodicity
Regular periodic variation of elements with atomic number and position in the periodic table
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Pi-bond
Overlap of p orbitals
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Propagation
Build up of products in a chain reaction
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Radical
Species of an unpaired electron
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Relative atomic mass
The weighted mean mass of an atom of an element compared with one-twelfth of the mass of an atom of carbon-12.
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Relative formula mass
The weighted mean mass of a formula unit compared with one- twelfth of the mass of an atom of carbon-12.
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Relative isotopic mass
The mass of an atom of an isotope compared with one-twelfth of the mass of an atom of carbon-12.
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Relative molecular mass
The weighted mean mass of a molecule compared with one- twelfth of the mass of an atom of carbon-12
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Saturated hydrocarbon
Single c-c bonds
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Specific heat capacity
q=mc🔺t
C=4.18
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Standard conditions
Pressure of 100kPa
Temperature of 298K
Concentration of 1 mol dm-3
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Stereoisomers
Same structural formula but different arrangement of atoms in space
61
Structural isomers
Same molecular formula but different structural arrangement of atoms
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Substitution reaction
An atom or group of atoms is replaced
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Termination
Two radicals combine to form a molecule
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