13 - nitrogen Flashcards
nitrogen facts
. non metallic element
. main unreactive gas in air
. makes up 78% of the atmosphere
. exists as diatomic molecules
electronic configuration of nitrogen
1s² 2s² 2p³
nitrogen bonding
triple covalent bond
why does nitrogen only react in extreme conditions?
it has a very strong triple bond which is difficult to break
bond energy of nitrogen triple bond
1000 kJ mol-1
bond energy of nitrogen triple bond
1000 kJ mol-1
nitrogen and oxygen reaction in air (due to thunderstorm)
(1) N2 + O2 –> 2NO
- NITROGEN (II) OXIDE
(2) 2NO + O2 –> 2NO2
- NITROGEN (IV) OXIDE
(3) 2NO2 + H2O + 0.5O2 –> 2HNO3
- NITRIC ACID
this nitric acid gets into soil, is absorbed by plants, nitrate ions are used by plants to make proteins for growth
test for ammonia gas
damp red litmus turns blue
Habers process reaction
N2 + 3H2 =REVERSIBLE = 2NH3
bonding in ammonia
triangular pyramidal
nitrogens lone pair of electrons can be donated to form a coordinate bond, structure?
H. +
H N ->H
H
positive charge evenly spread
NH3 + H+ — > NH4 +
ammonia is a strong/weak acid/base
weak base
equilibrium mixture in aqueous solution of ammonia
NH3 + H2O =REVERSIBLE= NH4+ + OH-
position of equilibrium is on left
reaction to prepare ammonia gas in lab
2NH4Cl + Ca(OH)2 —>HEAT—>CaCl2 + 2H2O + 2NH3
this is an acid base reaction
how to see if unkown compound has ammonium ions
heat it with base, ammonia gas test
what is inside an engine
. mixture of air (nitrogen- 78%, oxygen - 21%)
. fuel
in this high temperature and pressure, nitrogen can form nitrogen oxides
nitrogen oxides cause:
. acid rain
. photochemical smog
acid rain
2NO + O2 == 2NO2
NO2 + H2O + 1.5O2 —> 2HNO3
. this nitric acid is in tiny droplets making up clouds
. droplets larger
. temperature drops
. clouds rise
. drops, containing dilute nitric acid and dilute sulfuric acid, falls as acid rain
NITROGEN OXIDES ACT AS CATALYSTS IN SULFURIC ACKD REACTIONS
SO2 oxidised to SO3
SO3 + H2O —> H2SO4
SO2 + NO2 —> SO3 + NO
NO + 0.5O2 —> NO2
continues
photochemical smog
primary pollants - eg nitrogen oxides as they’re given off directly into air from source, VOCs
not
secondary pollutants - not given off directly from human activity
VOCs: volatile organic compounds
. unburnt hydrocarbons from fuel and their oxidised products
. can react in sunlight to make PAN
PAN: peroxyacetyl nitrate
- organic pollant made by reactions with nitrogen oxides in sunlight, causing photochemical smog
- formula CH3CO3NO2
primary pollutants
eg nitrogen oxides as they’re given off directly into air from source, VOCs
secondary pollutants
not given off directly from human activity
VOC
volatile organic compounds
. unburnt hydrocarbons from fuel and their oxidised products
. can react in sunlight to make PAN
PAN
peroxyacetyl nitrate
- organic pollant made by reactions with nitrogen oxides in sunlight, causing photochemical smog
- formula CH3CO3NO2
- affexts lungs, eyes, plant life
- very harmful
