Chemical Industry 1: Nitrogen Chemistry Flashcards
Be able to draw dot criss diagrams for nitrogen compounds:
N2, NH3, NH4+
Look at sheet
What is special about bonding in NH4+
Dative Covalent bond between N and one of the H ( N donates 2 of its electrons to an H )
NH3 = ?
AmmoniA
NH4+ = ?
AmmoniUM
Name 3 nitrogen oxides and give their formula
- Nitrogen monoxide ( NO )
- Dinitrogen monoxide ( N2 O)
- Nitrogen dioxide ( NO2)
What are other names for nitrogen monoxide ( NO )
- nitrogen ( II ) oxide
- nitric oxide
Appearance of NO
Colourless gas
Sources ( where does it come from ) of NO
- Natural = lightening, forest fires, denitrifying bacteria
- Human = combustion of fuels - driving vehicle / to generate electricity
( N2 + O2 combine in high heat of an engine )
What are other names for dinitrogen monoxide ( N2O )
- nitrogen ( I ) oxide
- nitrous oxide
Appearance of N2O
Colourless gas
Sources ( where does it come from ) of N2O
- in soil by denitrifying bacteria
What are other names for nitrogen dioxide( NO2 )
- nitrogen ( IV ) oxide
Appearance of NO2
Brown gas
Sources ( where does it come from ) of NO2
- oxidation of NO in air
Write balanced equation for formation of nitrogen ( II ) oxide
N2 (g) + O2 (g) —> 2NO (g)
Write balanced equation for conversion of nitrogen ( II ) oxide to nitrogen ( IV ) oxide
2 NO(g) + O2(g) —> 2 NO2(g)
Be able to draw dot and Ross diagrams of the nitrate ions
- nitrate ( V ) ion ( NO3- )
- nitrate ( III ) ion ( NO2- )
Look at sheet
What is the solubility of nitrate ions like
Both nitrate ions are VERY SOLUBLE in water
NO3- = ?
Nitrate ( V ) ion
because oxidation of N = +5
NO2- =?
Nitrate ( III ) ion
because oxidation state of N = +3
5 stages of nitrogen cycle
- Nitrogen Fixation
- Absorption by plants
- Moving along food chains
- Death of organisms
- Dentrification
Explain 1st stage of nitrogen cycle - Nitrogen fixation
nitrogen in atmosphere to unreactive to be used directly has to be changed into soluble ions
nitrogen fixing bacteria in roots nodules of legumes will convert nitrogen into nitrate
lightening converts nitrogen into nitrates
Haber process will convert nitrogen into ammonia & nitrifying bacteria will turn ammonia into nitrates
Explain 2nd stage of nitrogen cycle - Absorption by plants
plants will absorb nitrates through roots by active transport
Explain 3rd stage of nitrogen cycle - moving along food chain
animals will eat plants and nitrogen from plants protein will become protein in animal
nitrogen is also passed from one animal to another by feeding
Explain 4th stage of nitrogen cycle - death of organisms
decomposers ( bacteria and fungi ) will break down urea, egested material and dead bodies & nitrogen compounds will be returned to the soil as ammonium ions
nitrifying bacteria will convert ammonia ions into nitrates for plants to absorb
Explain 5th stage of nitrogen cycle- Denitrification
denitrifying bacteria in the soil will break down nitrates and return nitrogen gas into the air
occurs in waterlogged soil so can be prevented by reducing drainage
Name 5 conversions within the nitrogen cycle
- Nitrification= NO2- —> NO3-
- Denitrification= NO3- —> N2
- Putrefaction= NH4+ —> NH3
- Ammonia Synthesis= N2- —> NH3
- In atmosphere= NO —> NO2
Describe 6 steps of nitrogen cycle in terms of how nitrogen compounds formed/ converted one after the other
- Nitrogen gas ( N2 ) —> AmmoniA ( NH3 )
- AmmoniA ( NH3 ) —> Ammonium ions ( NH4+ )
- Ammonium ( NH4+ ) —>
Nitrites/ Nitrate ( III ) ions ( NO2-) - Nitrites/ nitrate ( III ) ions ( NO2- ) —> NitrAtes / nitrate ( V ) ions ( NO3-)
- NitrAtes/ nitrate ( V ) ions ( NO3-) —> Nitrogen ( N2 in atmosphere)
- Nitrogen gas ( N2) —> nitrogen oxides ( NO, NO2, N2O )
Write an equation of the formation of nitrate ( III ) ion from an ammonium ion
NH4+ + 1.5 O2 —> NO2- + 2 H+ + H20
Write an equation of the formation of the nitrate ( V ) ion from nitrate ( II ) ion
NO2- + 0.5 O2 —> NO3-
Describe test for nitrate ( V ) ion ( NO3- )
- Warm solution with sodium hydroxide ( NaOH )
- Add aluminium foil
- ( in presence alkali ) aluminium reduces nitrate ion to produce ammonia gas
- Ammonia gas = damp red litmus —> blue
Describe test for ammonium ion ( NH4+ )
- Add sodium hydroxide ( NaOH )
- Heat gently
- Ammonia ( NH3 ) has produced = turn red damp litmus paper blue
Equation of ammonium ion to ammonia gas in presence of alkali
NH4+ (aq) + OH- (aq) —> NH3(g) + H2O (l)
Describe the bonding in nitrogen
Triple bond in N atoms requires a lot of energy to break
