Yellow booklet answers page 120 – 152 (last page of yellow booklet)
(Air, Water, The Haber Process, The Contact Process)
Air (page 120 – 131)
Pg 120
1. mixture, nitrogen, 79%
2. Noble gases, argon
3. glowing
4. B
Pg 121
5. A
6. B
7. B
8. B
Pg 122
9. C
10. B
Pg 123
1. fractional distillation, expansion, boiling points
2. carbon dioxide, soot, carbon monoxide
3. energy, water vapour, carbon dioxide
4. C
5. D
Pg 124
6. a) Incomplete combustion produces soot (carbon), carbon monoxide and water vapour;
carbon monoxide is poisonous
b) (i) respiration
(ii) glucose from foodstuff
c) (i) welding (using oxyacetylene flame)
(ii) carbon dioxide and water vapour
7. a) 79%, 20%
b) (i) presence of ice (from water vapour) will result in b.p. elevation of other liquefied gases; prevent blockage of the pipes by solid carbon dioxide and ice
(ii) nitrogen, argon, oxygen and krypton
Pg 125
1. carbon monoxide, unburnt hydrocarbons
Pg 126
2. oxides of nitrogen
3. incomplete
4. sulphur, sulphur dioxide, sulphurous acid (H2SO3)
5. ozone
6. nitrogen, carbon dioxide
7. desulphurization
8. D
9. A
10. A
Pg 127
11. a) methane
b) sulphur dioxide
c) ozone
d) unburnt hydrocarbons / carbon monoxide / nitrogen oxides
e) sulphur dioxide
f) nitrogen oxides
12. a) reacts with water vapour and oxygen in the atmosphere, forming acid rain, which corrodes buildings and destroys crops
b) (i) Mg(OH)2 + SO2 à MgSO3 + H2O
(ii) Neutralization
c) (i) MgSO3 à MgO + SO2
(ii) Manufacture of sulphuric acid in the Contact Process
(iii) Recycled / reused to absorb more sulphur dioxide
Pg 128
13. a) From secondhand smoke
b) Vol = 0.01% of 10 dm3 = 1 cm3
c) Incomplete combustion from the cigarette
d) Non-smoker
e) Forms carboxyhaemoglobin in blood, prevent transport of oxygen hence breathing difficulty.
Pg 129
carbon cycle
combustion, photosynthesis
carbon dioxide
a) CO + O3 à CO2 + O2
b) 2NO + 2CO à 2CO2 + N2
c) Catalytic converters
Pg 130
a) carbon dioxide, water vapour, energy
b) Respiration and combustion use up oxygen, carbon dioxide produced, photosynthesis uses up carbon dioxide, oxygen produced.
c) Melting of polar ice caps à flooding of coastal (low-lying) areas
Decrease in crop yields à desertification
Pg 131
a) (i) Incomplete combustion of fuel (petrol)
(ii) carbon dioxide 2CO + O2 à 2CO2
b) (i) 2NO2 à N2 + 2O2 or 2NO à N2 + O2
(ii) reacts with oxygen and water vapour in atmosphere, producing acid rain
c) (i) Substance that speeds up rate of reaction without forming products or used up (i.e. no chemically involved).
(ii) The purpose of the catalysts is different thus use of catalyst is different.
a) Ozone layer blocks harmful uv rays responsible for skin cancer. Ozone holes allow passage of uv rays.
b) Source: reaction of unburnt hydrocarbons with nitrogen dioxide in sunlight
Effect: breathing difficulties
c) (i) Try it out yourself. You should be able to draw the covalent molecule.
(ii) HFCs do not decompose, when exposed to sunlight, forming free radicals
Water (page 132 – 137)
Pg 132
anhydrous, white, blue
mineral salts
phosphates
eutrophication
D
D
Pg 133
a) (i) Atoms of same element with different mass numbers
(ii) H-1 : 1 proton, 0 neutron
H-2 : 1 proton, 1 neutron
b) (i) Helium does not react with oxygen / Mixture of H2 and O2 explodes with small sparks
(ii) Reaction of H2 and O2 very exothermic, great deal of heat produced to propel rocket / No reaction between helium and oxygen.
a) Compound: Formed from chemical reaction, 2 or more different substances chemically combined
Exothermic: Reaction in which (heat) energy is given out / produced
Elements: Substances that cannot be further decomposed into anything simpler
b) 2H2 + O2 à 2H2O
c) You should be able to draw the energy profile diagram on your own. It’s an exothermic reaction so the energy level of products is lower than the energy level of reactants.
Pg 134
Chlorine
activated carbon
desalination
a) filtration – to remove fine suspended solid particles
chlorination – to kill harmful bacteria
Pg 135
4. b) (i) Sea water
(ii) Nitrate
(iii) Distillation
c) (i) Salt
(ii) Desalination
d) Test 1: White anhydrous copper (II) sulphate à blue
Test 2: Blue cobalt (II) chloride paper à pink
Pg 136
5. a) (i) D
(ii) B
(iii) Na2SO4, NaNO3, Ca(NO3)2 but not CaSO4 (insoluble)
(iv) A. High concentration of sulphate ions and nitrate ions found in fertilizers.
b) 4Fe2+ (aq) + 4H+ (aq) + O2 (g) à 4Fe3+ (aq) + 2H2O (l)
How to do it???
1) Write out the reactants, ions, compounds, etc involved.
2) Balance the number of ions / atoms / etc on each side of the equation
3) Check to ensure that the overall charge on each side of the equation is the same. The charges do not necessary have to add up to 0 on both sides.
Pg 137 (Crossword puzzle)
1) Ammonia
2) Anhydrous
3) Sodium
4) Margarine
5) Extinguished
6) Drink
7) Kitchen
8) Neutral
9) Lighted
10) Decompose
11) Explosion
12) Natural
13) Liquid
14) Distillation
15) Non
The Haber Process (page 138 – 146)
Pg 138
alkaline, moist, blue
ammonium, alkali
Pg 139
Haber, 200, 450°C
reversible
A
B
D
D
Pg 140
a) Increase pressure, increases %NH3
b) (i) 27%
(ii) Advantage: Low temp makes reaction slow. Hence at 450°C, reaction proceeds faster than at 350°C.
Disadvantage: At same pressure, %NH3 at 450°C is lesser than %NH3 at 350°C.
c) Catalysts are not used up in the reaction and can be recycled.
d) Moist red litmus turns blue in ammonia.
Lighted splint extinguished with ‘pop’ in hydrogen.
Glowing splint rekindled in oxygen.
Pg 141
proteins
eutrophication
nitrogen
Pg 142
C
D
B
A
a) %N in NaNH2 = 35.9% (to 3 s.f.)
Mass required to produce 14 tonnes nitrogen = 39
%N in (NH2)2CO = 46.7% (to 3 s.f.)
Mass required to produce 14 tonnes nitrogen = 30
Thus urea (NH2)2CO provides more nitrogen per tonne of fertlizers.
Pg 143
8. b) High solubility of nitrate ions washed into nearby rivers (leaching); growth of algae in rivers encouraged; algae dies and decays, oxygen is used up; oxygen content depleted / decreased
c) (i) 2NH4NO3 + Ca(OH)2 à Ca(NO3)2 + 2H2O + 2NH3
(ii) Reduce acidity of soil
(iii) Calcium hydroxide reacts with ammonium nitrate, producing calcium nitrate which is a neutral salt, water and ammonia.
Nitrogen is displaced from fertilizers, and not used to increase nitrogenous content of the soil; thus wasted.
Pg 144
9. a) (i) 2850 kg (estimated from half of (2600 kg + 3100 kg))
(ii) From 20 kg of phosphorus added onward, very slight increase to potato yield per kg.
b) (i) Mr of Ca(H2PO4)2 = 234
(ii) %P in Ca(H2PO4)2 = 26.5% (to 3 s.f.)
Mass to be provided = 56.6 kg (to 3 s.f.)
(iii) Potassium nitrate, KNO3
Pg 145
10. a) Necessary for plant growth and repair of plant cells (synthesis of proteins)
b) 2NH3 + H2SO4 à (NH4)2SO4
c) %N in NH4NO3 = 35%
%N in (NH4)2SO4 = 21.2%
%N in urea = 46.7% (highest %N by mass)
d) You should be able to draw the covalent molecule of ammonia. If not, please check your textbook.
Pg 146 (Fun with Chemistry)
UREA
POTASSIUM
CHLOROPHYLL
AMMONIUM NITRATE
PROTEIN
BACTERIA
LIME
NITROGEN
TRACE ELEMENTS
The Contact Process (pg 147 – 152)
Pg 147
S8, low, yellow
sulphur dioxide, pungent, acid rain
preservative, bleach
D
Pg 148
SO2, vanadium (V) oxide, 450°C, 1 atm
water, sulphuric acid, oleum
fertilizers
C
Pg 149
C
E
D
B
Pg 150
a) Manufacture of fertilizers
b) Sulphuric acid with barium nitrate solution; white precipitate of barium sulphate produced
c) (not in graph) As an electrolyte in car batteries / making of detergents
d) Reaction: H2SO4 + MgCO3 à MgSO4 + CO2 + H2O
Observation: Effervescence / bubbles of gas produced
Products: magnesium sulphate, carbon dioxide and water
10. a) (i) Ammonium sulphate
(ii) Plants need other elements (like potassium and phosphorus) for healthy growth, thus other fertilizers needed to provide the K and P.
Pg 151
10. b) (i) 3H2SO4 + Fe2O3 à Fe2(SO4)3 + 3H2O
(ii) Acid will react with iron in steel sheets.
c) (i) 2SO2 + O2 2SO3
(ii) 450°C, 1 atm, with vanadium (V) oxide as catalyst
(iii) Sulphur dioxide gains oxygen, forming sulphur trioxide, thus oxidation (gain of oxygen) OR
Increase in oxidation state of sulphur from +4 to +6 thus oxidation.
d) (i) Use of sulphur dioxide: as a food preservative;
as a bleaching agent for wood pulp
(ii) Add / pass / bubble gaseous compound into
1. acidified potassium dichromate (VI) solution; turns from orange to green
2. acidified potassium manganate (VII) solution; turns from purple to colourless
Pg 152 (Fun with Chemistry)
1. sulphide
2. sulphurous
3. electrolyte
4. pickling
5. hydrogen
6. anhydride
7. trioxide
8. fertilizers (end of yellow bookle
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