Definitions Flashcards
Define isotopes
Isotopes are atoms of the same element with different numbers of neutrons and different masses
Define relative atomic mass
The relative atomic mass for an element is the weighted mean mass of an atom of the element compared with 1/12th the mass of an atom of carbon-12 which has a mass of 12
Define relative isotopic mass
The mass of one isotope relative to 1/12th the mass of a carbon-12 atom which has a mass of 12
Define mole
The amount of substance which contains as many elementary particles as there are atoms in exactly 12g of carbon-12
Define molar mass
The mass of one mole of substance
Define molar gas volume
The volume per mole of gas molecules at a stated temperature and pressure
Define Lowry-Bronsted acid
A proton donor
Define alkali
A substance which releases -OH in solution
Define Lowry-Bronsted base
A proton acceptor
Define a salt
A substance produced when the H+ ion of an acid is replaced by a specific metal ion or NH4+
Define an orbital
A region of space that can hold up to two electrons with opposite spin
Define first ionisation energy
The energy required to remove one electron from each atom in one mole of gaseous atoms to make one mole of gaseous unipositive ions
Define second ionisation energy
The energy required to remove one electron from each unipositive ion in one mole of gaseous unipositive ions to make one mole of gaseous dipositive ions
Define covalent bond
The electrostatic attraction between a positively charged nucleus and a shared pair of electrons
Define dative covalent bond
A covalent bond where only one of the bonded atoms donates both electrons being shared
Define electronegativity
The power of attraction between a bonded atom and a pair of electrons in a covalent bond
Define hydrogen bonding
The interaction between the lone pair of electrons on a nitrogen, oxygen or fluorine atom and a hydrogen atom which is bonded to an N, O or F atom
Define ionic bond
The electrostatic attraction between oppositely charged ions
Define metallic bond
The electrostatic attraction between positively charged metal ions and delocalised electrons
Define periodicity
The repeating pattern of properties of elements across different periods in the Periodic table
Define disproportionation
When an element is being both oxidised and reduced in a redox reaction
Define the rate of reaction
The change in concentration of reactant or product per unit time
Define Le Chatelier’s Principle
When a system under dynamic equilibrium is subjected to a change, the equilibrium will shift so as to oppose the change
Define standard conditions
Temp= 298K, Pressure= 100kPa, solution conc= 1moldm-3
Define standard enthalpy of formation
The enthalpy change when 1 mole of a compound is formed in its standard state from its constituent elements in their standard states, under standard condition
Define standard enthalpy of combustion
The enthalpy change when 1 mole of a substance in its standard state reacts completely with oxygen under standard conditions
Define standard enthalpy change of neutralisation
The enthalpy change when 1 mole of water is created by the neutralisation of an acid with an alkali under standard conditions
Define homologous series
A series of organic compounds with the same functional group but with each successive member differing by CH2
Define structural isomer
Have the same molecular formula but a different structural formula
Define homolytic fission
Where the covalent bond breaks equally so each product receives one of the shared pair of electrons to form radicals
Define heterolytic fission
Where the covalent bond breaks unequally so one product gets both of the electrons from the shared pair and the other gets nothing, producing ions
Define radical
A species with an unpaired electron
Define nucleophile
Electron pair donor
Define electrophile
Electron pair acceptor
Define sigma bond
Sigma bonds are formed by the direct overlap of orbitals directly between the bonding atoms
Define stereoisomerism
Compounds with the same structural formula but a different arrangement of atoms in space
Define IR spectroscopy
Method used to identify which functional groups are present in a given molecule
Define fingerprint region
Unique to a particular molecule, used to identify known substances from a database
Define half life
The time taken for the concentration of one reactant to fall by half the original value
Define the rate determining step
The slowest step in the reaction mechanism of a multistep reaction which determines the overall rate
Define partial pressure
The pressure exerted if one gas in a mixture occupied the whole container alone
Define Ka
[H+][A-]/ [HA]
Define buffer
A solution that resists changes in pH when small amounts of acid or alkali are added
Define standard electrode potential
The voltage measure when the named electrode is connected to the standard hydrogen electrode at 298K under 100kPa with solutions of 1 moldm-3
Define fuel cell
A fuel cell uses the energy generated from the reaction between a fuel and oxygen to create a voltage
Define transition metal
A d-block element that forms one or more stable ions with incompletely filled d-orbitals
Define complex
A complex consists of a central metal ion/metal surrounded by ligands which are bonded coordinately
Define ligand
A molecule or ion which donates a lone pair of electrons to the transition metal by coordinate bonding
Define coordination number
The number of coordinate bonds in the complex
Define bidentate
Some ligands can donate two pairs of electrons to make two coordinate bonds
Define arenes
Compounds which contain unsaturated rings with delocalised electrons within the ring
Define chiral centre
A carbon with 4 different groups/atoms attached to it
Define condensation polymerisation
The joining of bifunctional monomers with the elimination of a small molecule such as water or HCl
Define lattice enthalpy
The energy change when 1 mole of solid ionic compound is formed from its ions in the gaseous state under standard conditions of 298K and 100kPa
Define atomisation of metal/non-metal
The energy change when 1 mole of gaseous atoms are formed from the element in its standard state
Define first ionisation of metal
The energy change when each atom in 1 mole of gaseous atoms loses 1 electron to become 1 mole of gaseous unipositive ions
Define electron affinity
The energy change when one mole of atoms gain 1 mole of electrons in the gaseous state
Define enthalpy of hydration
The energy change when 1 mole of gaseous ions are completely hydrated by water
Define enthalpy of solution
The energy change when 1 mole of a solute in dissolved in water
What is the gradient of the graph of ln k against 1/T?
-Ea/R
What is the intercept of the graph of ln k against 1/T?
lnA
