pblock elements: Nitrogen

1
p-block elements Nitrogen

• About N2
• Non-metal
• Colourless and odourless gas
• Low melting point
• Less dense than air
• Slightly soluble in water
• Does not support combustion

2
p-block elements Nitrogen

• How important is N2?
• Making protein in all living things
• Making NH3 which is a very useful

Climbing ropes made by nylon
As a coolant in laboratories
Uses of NH3 80 fertilizers, 7 nylon, 5 HNO3
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p-block elements nitrogen

• Characteristic properties of nitrogen
• Formation of NOx
• Formation of photochemical smog
• NH3 (Haber process/chemical properties)
• HNO3(Ostwald process/chemical properties)
• Nitrates(V) (action of heat/brown ring test)

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p-block elements Nitrogen
Characteristic properties of nitrogen Unreactive
(extremely strong triple bond and absence of bond
polarity)
NHe2s22p3 N?N 944 kJ mol-1 F F 158 kJ
mol-1
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p-block elements Nitrogen
Formation of NOx
lightning
N2 O2 ? 2NO 2NO O2 ? 2NO2 NO2 H2O ? HNO2
HNO3
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p-block elements Nitrogen
Formation of photochemical smog
Car engine
N2 O2 ? 2NO 2NO O2 ? 2NO2 NO2 ? NO O
sunlight
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p-block elements Nitrogen
NH3 (Haber process)
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NH3 (chemical properties) weak base, neutralize
acid, providing OH-, form complex with Zn2 ,Cu2
and Ag
NH3 H2O ? NH4 OH-
2NH3 H2SO4 ? (NH4)2SO4
2NH3 Ca2 2H2O? Ca(OH)2 2NH4
Forming Zn(NH3)42,Cu(NH3)42and Ag(NH3)2
9
NH3 (chemical properties) as reducing agent
4NH3(g) 3O2(g)? 2N2(g) 6H2O(g) 4NH3(g)
5O2(g) ? 4NO 6H2O(g)
2NH3(g) 3CuO(s) ? 3Cu(s) N2(g) 3H2O(g)
10
HNO3 (Ostwald process/chemical properties)

• HNO3
• Decompose by light
• 4HNO3(l) ? 4NO2 2H2O(l) O2(g)
• Ostwald process
• Oxidize Cu, Fe2, S and form NO2

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HNO3 (Ostwald process)
This man holding a large gauze of rhodium
platinum wire for use as catalyst in oxidation of
NH3
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p-block elements nitrogen
Nitrates(V) (action of heat/brown ring test)
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p-block elements nitrogen
Nitrates(V) (action of heat/brown ring test)
brown ringFeSO4?NO(aq)