definitions Flashcards
atomic number
no. of protons
mass number
total no. of protons and neutrons
isotopes
atoms with the same number of protons but a different number of neutrons
TOF mass spectrometer
analytical instrument that gives accurate information about relative isotopic mass and relative abundance of isotopes
electrospray ionisation?
high voltage applied to sample dissolved in a polar solvent molecules lose an electron form gaseous 1+ ions must be ionised so they can be accelerated towards negatively charged plate
relative mass
the weighted mean mass of an atom of an element relative to 1/12 of the mass of one atom of carbon-12
first ionisation energy
the energy required to remove an electron from each atom in one mole of gaseous atoms
what is an acid?
a species that is a proton donor
activation energy?
the minimum energy required to start a reaction by the breaking of bonds
addition polymer
the process in which unsaturated alkene molecules add on to a growing polymer chain one at a time to form a very long saturated molecule chain
addition reaction
a reaction in which a reactant is added to an unsaturated molecule to make a saturated molecule
adsorption
the process that occurs when a gas liquid or solid is held to the surface of a solid (RARELY A LIQUID)
alkali?
a type of base that dissolves in water forming hydroxide ions
alkanes?
the homologous series with the general formula cnH2n+2
alkyl group?
an alkane with a hydrogen ion removed
alkyl groups are often shown as ‘R’
what does anhydrous mean?
substance containing no water molecules
what is an anion?
a negatively charged ion
atom economy?
molecule mass of the desired product/sum of molecular masses of all products x 100
atomic orbital?
a region within an atom that can hold up to two electrons with opposite spins
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 substance
avogadro constant?
6.022 x 10^23
what is a base?
species that is a proton acceptor
bond enthalpy
the enthalpy change that takes place when breaking, by homolytic fission, 1 mol of a given bond in the molecules of a gaseous species
catalyst?
a substance that increases the rate of a chemical reaction without being used up
cation?
positively charged ion
cis - trans isomerism?
type of E/Z isomerism in which there is a non-hydrogen group and a hydrogen on each side of a C=C double bond:
the cis isomer has the H atom of each carbon on the same side
the trans has the H atom of each carbon on different sides
concnetration?
amount of solute in solvent
mol per dm^2
coordinate bond / dative covalent bond
a shared pair of electrons which has only been provided by one of the bonding atoms
covalent bond?
bond formed by a shared pair of electrons
what is cracking?
the breakdown of long-chained saturated hydrocarbons to form a mixture of shorter-chained alkanes and alkenes
what is dehydration?
an elimination reaction in which water is removed from a saturated molecule to make an unsaturated molecule