CI

Question 1

describe nitrogen gas

Answer 1

• low reactivity due to strong triple covalent bond
• high bond enthalpy
• bonds must be broken (partially) in order to react

Question 2

describe ammonia

Answer 2

NH3
aka nitrogen hydride
has a lone pair so can form dative covelent bonds

Question 3

describe an ammonium ion

Answer 3

NH4+
has dative covalent bond with hydrogen

Question 4

describe nitrogen oxide

Answer 4

NO
- colourless gas that will turn brown (NO2) in air
- formed by combustion processes, thunderstorms, denitrifying bacteria

Question 5

describe nitrogen dioxide

Answer 5

NO2
- brown gas formed by the oxidation of NO

Question 6

describe Dinitrogen oxide

Answer 6

N2O
- colourless gas formed in soil by denitrifying bacteria

Question 7

what are the two nitrate ions in the nitrogen cycle

Answer 7

• nitrate (III), NO2- aka nitrite
• nitrate (V), NO3-
  both are very soluble in water

Question 8

how are the nitrate ions formed

Answer 8

by nitrification
- ammonium ions oxidised by aerobic bacteria
NO2- formed first then quickly oxidised to NO3-

Question 9

how can nitrate V be tested for

Answer 9

• sodium hydroxide with Devarda’s alloy (Cu/Al/Zn)
• gently heated
• ammonia gas produced
• ALSO USE BROWN RING TEST

Question 10

how can ammonium iopns be tested for

Answer 10

gently heat with sodium hydroxide solution
- ammonia gas produced

Question 11

how do you test for ammonia

Answer 11

• sharp smell
• turn damp red litmus paper blur
• white fumes when with HCl

Question 12

describe the Haber process

Answer 12

N2 + 3H2 —> 2NH3
- high temp, pressure and iron catalyst

Question 13

what do dotted lines in double bonds show

Answer 13

delocalisation across the molecule
- bonds exist at any specific moment in time

Question 14

what is the equation for the formation of nitrate (III)

Answer 14

NH4+ + 1.5O2 –> NO2- +2H+ + H2O

Question 15

what is the equation for the formation of nitrate (V)

Answer 15

NO2- + 0.5O2 —> NO3-