Chemical Industry Flashcards
how can you follow rate of reaction?
ph
gas vol
loss of mass
colour change
titration
initial rate =
amount of reactant used or formed / time
how do you do the initial rate method?
time how long it takes for specific vol of gas to form then repeat using different concentrations of one reactant
iodine clock reaction equation is…
H2O2 + 2I- + 2H+ —> 2H2O + I2
what is the rate equation?
rate = k [A]^m x [B]^n
the bigger the rate constant…
the faster the reaction
how does a zero order reactant affect rate?
changing concentration has no effect on rate
how does a first order reactant affect rate?
if the concentration increases, rate increases proportionally
e.g. if conc doubles, rate doubles
how does a second order reactant affect rate?
if the concentration increases, rate increases proportionally squared
e.g. if conc doubles, rate quadruples
what is half life?
the half life of a reaction is the time it takes for half the reactant to be used up
as a reaction goes on the half life of a zero order reactant…
decreases as the reaction goes on
as a reaction goes on the half life of a first order reactant…
remains constant
as a reaction goes on the half life of a second order reactant…
increases as it goes on
you can find rate constant from….
half life and first order
does changing temperature affect rate constant?
yes
a calculated rate constant is only valid at…
a certain temperature
at a higher temperature rate constant…
will be higher
the arrhenius equation links…
rate constant and activation energy
what is the arrhenius equation?
k = (-Ea)/RT
what is the equation for equilibrium constant?
aA + bB —> dD + eE
Kc = [D]^d x [E]^e / [A]^a x [B]^b
if temperature is increased @ equilibrium
eqm shifts in the endothermic direction
if temperature is decreased @ equilibrium
eqm shifts in exothermic direction
if the increase in temperature means product yield increases…
Kc will increase