Topic 5- Physical chemistry and Transition elements Flashcards
reaction rate
change in quantities of reactants or products over time
zero order
concentration of reactant has no effect on rate
first order
rate depends on its concentration raised to the power of 1
second order
rate depends on its concentration raised to the power of 2
overall order
sum of orders with respect to each reactant
zero order concentration-time graph
straight line with a negative gradient
first order concentration-time graph
downwards curve with a decreasing gradient over time
constant half life
half life
time taken for half of a reactant to be used up
zero order rate-concentration graph
horizontal straight line with a gradient of 0
first order rate-concentration graph
straight line through the origin
rate and concentration directly proportional
second order rate-concentration graph
upward curve with increasing gradient
initial rate
instantaneous rate at the start of a reaction when the time=0
reaction mechanism
series of steps that make up an overall reaction
rate determining step
slowest step in the sequence
arrhenius equation
exponential relationship between rate constant and temperature
exponential factor
proportion of molecules that exceed Ea and have sufficient energy for the reaction to take place
homogenous equilibrium
equilibrium species that all have the same state or phase
heterogenous equilibrium
equilibrium species that have different states or phases
mole fraction
proportion by volume to the total volume of gases in a gas mixture
partial pressure
mole fraction x total pressure
effect on Kc when temperature increases
if forward reaction is exothermic the equilibrium will shift in the endothermic direction meaning the value of Kc will decrease
Bronsted-Lowry acid
proton donor
Bronsted-Lowry base
proton acceptor
conjugate acid-base pair
two species that can be interconverted by transfer of a proton
monobasic acid
an acid that contains only one hydrogen ion, which can be donated to a base
dibasic acid
an acid containing two hydrogen ions that can be donated to a base
tribasic acid
an acid containing 3 hydrogen ions that can be donated to a base
pH
numerical scale for measuring H+ ion concentration
stronger acid, larger…
Ka
stronger acid, smaller…
pKa
Kw
ionic product of water- ions in water multiplied together
buffer solution
system that minimises pH change when small amounts of acid or base is added
equilibrium shift when alkali added to a buffer
shifts right
H+ reacts with hydroxide ions
HA dissociates to restore H+ lost
equivalence point
volume of one solution that exactly reacts with the volume of the other solution
indicator is also a…
weak acid
lattice enthalpy
the enthalpy change that accompanies the formation of one mole of an ionic compound from its gaseous ions under standard conditions
standard enthalpy change of atomisation
the enthalpy change that takes place when one mole of gaseous atoms forms from the element in its standard state
first electron affinity
the enthalpy change that takes place when one electron is added to each atom in one mole of gaseous atoms to form one mole of gaseous 1- ions
second electron affinities are…
endothermic
standard enthalpy change of solution
the enthalpy change that takes place when one mole of a compound is completely dissolved in water under standard conditions
enthalpy change of hydration
the enthalpy change that takes place when one mole of isolated gaseous ions s dissolved in water forming one mole of aqueous ions under standard conditions
entropy
dispersal of energy and disorder within the chemicals making up a chemical system
feasibility
whether a reaction is able to happen
free energy change
overall change in energy
for a reaction to be feasible, delta G must be…
less than 0
metal/ metal ion half cell
metal rod dipped into a solution of aqueous metal ions
ion/ion half cells
same element in different oxidation sates with a platinum electrode
standard electrode potential
the e.m.f of a half cell compared with a standard hydrogen half cell, in standard conditions
salt bridge
allows ions to flow between solutions
d block element
an element with its highest energy electron in a d subshell
transition element
a d block element that forms an ion with a partially filled d subshell
complex ions
a transition metal ion bonded to ligands through dative covalent bonds
ligands
molecule or ion that donates a pair of electrons to a central metal ion to form a dative covalent bond
monodentate ligands
a ligand that is able to donate one pair of electrons to a central metal ion
bidentate ligands
ligand that can donate two pairs of electrons to the central metal ion forming two dative covalent bonds
ligand substitution
one ligand in a complex ion replaced with another ligand
