AS level Chemistry OCR new Spec Definitions (Physical and Inorganic Chemistry)

question

Relative Isotopic Mass
answer

mass of an isotope compared to 1/12th the mass of a carbon-12 atom
question

Relative Atomic Mass
answer

weighted mean mass of an atom compared to 1/12th the mass of a carbon-12 atom
question

1st Ionisation Energy
answer

energy required to remove one mole of electrons from one mole of gaseous atoms
question

Common Acids
answer

HCl, H2SO4, HNO3, CH3COOH
question

Common Alkalis
answer

NaOH, KOH and NH3
question

Acid
answer

releases H+ in aqueous solution
question

Alkali
answer

releases OH- in aqueous solution
question

Strong Acids
answer

fully disassociated in solution
question

Weak Acid
answer

partially disassociated in solution
question

Salts
answer

ionic compound formed when the H+ ion in acids are replaced by metal or ammonium ions
question

Amount of Substance
answer

means of counting the quantity of any species with unit of moles
question

Mole
answer

amount of any substance containing as many elementary particles as there are carbon atoms in 12g of carbon-12
question

Avogadro’s Constant
answer

6.02 X 10^23 particles
question

Molar Mass
answer

mass per mole of a substance
question

Empirical Formula
answer

simplest whole number ratio of atoms of each element present in a compound
question

Molecular Formula
answer

number and type of atoms of each element in a molecule
question

Anhydrous
answer

containing no water molecules
question

Hydrated
answer

a crystalline compound containing water molecules
question

Water of Crystallisation
answer

water molecules that are bonded into a crystalline structure of a compound
question

Ionic Bonding
answer

electrostatic attraction between positive and negative ions
question

Covalent Bonding
answer

electrostatic attraction between a shared pair of electrons and the bonding nuclei
question

Metallic Bonding
answer

strong electrostatic attraction between cations and delocalised electrons
question

Electronegativity
answer

ability of an atom to attract the bonding electrons in a covalent bond
question

Polar Bond/Permanent Dipole
answer

covalently bonded atoms with different electro-negativities
question

Periodicity
answer

repeating trends in physical and chemical properties across periods
question

Disproportionation
answer

oxidation and reduction of the same element
question

Endothermic
answer

the ∆H is positive, as bond breaking absorbs energy from the surroundings
question

Exothermic
answer

the ∆H is negative, as bond making releases energy into the surroundings
question

Activation Energy
answer

the minimum energy required for a reaction to take place
question

∆fH
answer

energy required to form one mole of a compound from its constituent elements
question

∆cH
answer

energy required for one mole of a substance to react completely with oxygen
question

∆neutH
answer

energy required to form one mole of water from a neutralisation reaction
question

Average Bond Enthalpy
answer

breaking of one mole of bonds in gaseous molecules
question

Homogeneous Catalyst
answer

same physical state as reactants
question

Heterogeneous Catalyst
answer

different physical state to reactants
question

Dynamic Equilibrium
answer

when the rate of the forwards reaction is the same as the rate of the reverse reaction in a closed system (concentration doesn’t change)

Get instant access to
all materials

Become a Member