13 - nitrogen

Question 1

nitrogen facts

Answer 1

. non metallic element
. main unreactive gas in air
. makes up 78% of the atmosphere
. exists as diatomic molecules

Question 2

electronic configuration of nitrogen

Answer 2

1s² 2s² 2p³

Question 3

nitrogen bonding

Answer 3

triple covalent bond

Question 4

why does nitrogen only react in extreme conditions?

Answer 4

it has a very strong triple bond which is difficult to break

Question 5

bond energy of nitrogen triple bond

Answer 5

1000 kJ mol-1

Question 6

bond energy of nitrogen triple bond

Answer 6

1000 kJ mol-1

Question 7

nitrogen and oxygen reaction in air (due to thunderstorm)

Answer 7

(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

Question 8

test for ammonia gas

Answer 8

damp red litmus turns blue

Question 9

Habers process reaction

Answer 9

N2 + 3H2 =REVERSIBLE = 2NH3

Question 10

bonding in ammonia

Answer 10

triangular pyramidal

Question 11

nitrogens lone pair of electrons can be donated to form a coordinate bond, structure?

Answer 11

H. +
H N ->H
H

positive charge evenly spread

Question 12

NH3 + H+ — > NH4 +

Question 13

ammonia is a strong/weak acid/base

Answer 13

weak base

Question 14

equilibrium mixture in aqueous solution of ammonia

Answer 14

NH3 + H2O =REVERSIBLE= NH4+ + OH-

position of equilibrium is on left

Question 15

reaction to prepare ammonia gas in lab

Answer 15

2NH4Cl + Ca(OH)2 —>HEAT—>CaCl2 + 2H2O + 2NH3

this is an acid base reaction

Question 16

how to see if unkown compound has ammonium ions

Answer 16

heat it with base, ammonia gas test

Question 17

what is inside an engine

Answer 17

. mixture of air (nitrogen- 78%, oxygen - 21%)
. fuel

in this high temperature and pressure, nitrogen can form nitrogen oxides

Question 18

nitrogen oxides cause:

Answer 18

. acid rain
. photochemical smog

Question 19

acid rain

Answer 19

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

Question 20

photochemical smog

Answer 20

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

Question 21

primary pollutants

Answer 21

eg nitrogen oxides as they’re given off directly into air from source, VOCs

Question 22

secondary pollutants

Answer 22

not given off directly from human activity

Question 23

VOC

Answer 23

volatile organic compounds

. unburnt hydrocarbons from fuel and their oxidised products
. can react in sunlight to make PAN

Question 24

PAN

Answer 24

peroxyacetyl nitrate

• organic pollant made by reactions with nitrogen oxides in sunlight, causing photochemical smog
• formula CH3CO3NO2
• affexts lungs, eyes, plant life
• very harmful

Question 25

what is photochemical reaction

Answer 25

reactions started by energy from ultraviolet, eg sun

Question 26

what are hydrocarbons

Answer 26

organic compound made up hydrogen and carbon only

Question 27

car exhaust system are fitted with…

Answer 27

catalytic converters

Question 28

catalytic converter reactions

Answer 28

2CO + 2NO —> 2CO2 + N2