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
if the increase in temperature means product yield decreases…
Kc will decrease
do pressure changes affect Kc?
no
do catalysts have affect on Kc?
no
colorimetry and ph readings can be used to…
find equilibrium concentrations
what kind of molecule is a nitrogen?
diatomic molecule
how many electrons are in nitrogen’s outer shell?
5
what is the electron configuration of nitrogen?
1s2 2s2 2p3
how do N atoms get a full shell?
they pair up and share 3 pairs of electrons between them
nitrogen atoms pair up and share..
3 pairs of electrons between them
nitrogen atoms pair up to form a…
triple bond
why is nitrogen unreactive
contains a triple bond that is hard to break
nitrogen forms three oxides that are…
- NO
- N2O
- NO2
NO is called…
nitrogen monoxide
NO (nitrogen monoxide) is a _____ gas
colourless
N2O is called….
nitrous oxide
nitrous oxide smells….
sweet
nitrous oxide is a _____ gas
colourless
NO2 is called…
nitrogen dioxide
NO2 (nitrogen dioxide) is ____ and ____
brown and toxic
NO2 (nitrogen dioxide) has a ___ ____
sharp odour
ammonias formula is…
NH3
N atoms form _____ bonds by sharing _ electron with each ____ . Leaving a ____ ____ on the nitrogen.
- covalent
- one
- hydrogen
- lone pair
why is ammomia soluble in water?
it can form hydrogen bonds with water
why can ammonia form dative covalent bonds?
it has a lone pair of electrons
the lone pair on the ammonia allows it to act as a…
base
what is the test for NH4+ ions?
- add NaOH to solution and heat
- if present they react with OH- ions and NH3 is produced
- red litmus turns blue
nitrates react with ammonia in the presence of…
alkali
the formula for nitrate ions is
NO3-
how do you test for nitrate (v) ions?
- warm solution with NaOH and aluminium foil (or Devarda’s alloy)
- if present ammonia gas will be produced
- so damp red litmus turns blue
which oxide containing nitrogen is brown and toxic?
nitrogen dioxide (NO2)
which oxide containing nitrogen has a sharp odour?
nitrogen dioxide (NO2)
which oxides containing nitrogen are colourless gases?
nitrogen monoxide (NO) and nitrous oxide (N2O)
which gas containing nitrogen smells sweet?
nitrous oxide (N2O)
if Ea increases k will….
this means the rate will….
get smaller
slow down
when temperature increases k will…
increase
what is seen when nitrogen monoxide gas reaches the atmosphere?
colourless gas turns brown
