Incorrect Questions- Paper 2

Question 1

Fossil fuels are burned in car engines.
Explain how reducing the amount of sulfur in fossil fuels reduces the erosion of limestone.?

Answer 1

sulfur reacts with oxygen to form sulfur dioxide
(so) less sulfur dioxide emitted
(so) less acid rain
(so less) limestone reacts with acid rain

Question 2

Liquid effluent and solid sewage sludge?

Answer 2

Liquid effluent= aerobic biological treatment
solid sewage sludge= anaerobic digestion

Question 3

Suggest one reason why only two spots are seen when there could multiple?

Answer 3

Some spots could be colourless

Question 4

Answer 4

Question 5

Answer 5

Starch and cellulose

Question 6

Answer 6

Nitrogen and ammonia

Question 7

Answer 7

incomplete / partial ionisation
(because) reaction is reversible

Question 8

Answer 8

(0.01 mol/dm3) methanoic acid has a lower pH
(so 0.01 mol/dm3) methanoic acid has a higher concentration of hydrogen ions
(therefore) more collisions per unit time

Question 9

Answer 9

ethyl ethanoate

Question 10

Answer 10

two polymer chains
four (different) monomers / nucleotides
(double) helix

Question 11

Answer 11

becomes (more) red
(because the position of)
equilibrium moves to the right
(so that) the (increase in the) concentration of thiocyanate (ions) is reduced

Question 12

Answer 12

Structure and bonding
• both are hydrocarbons
• ethane contains six hydrogen atoms (per molecule)
• (but) ethene contains four hydrogen atoms (per molecule)
• both have covalent bonds
• ethane contains a single C C bond
• (but) ethene contains a double bond

Reactions
• both react with oxygen in complete combustion reactions
• to produce water and carbon dioxide
• both react with oxygen in incomplete combustion reactions
• to produce water, carbon monoxide and carbon
• incomplete combustion is more likely with ethene
• ethene decolourises bromine water
• (but) ethane does not decolourise bromine water
• ethene is more reactive (than ethane)
• ethene can react with hydrogen (to produce ethane)
• ethene can react with water (to produce ethanol)
• ethene can react with halogens (to produce halogenoalkanes)
• ethene can undergo addition reactions
• ethene can polymerise (to produce poly(ethene))

Question 13

Mg to g?

Answer 13

X100

Question 14

Stainless steal with corrosion?

Answer 14

-stainless steal is resistant to corrosion (nickel and chromium)

Question 15

Answer 15

no effect (on yield of hydrogen)

Question 16

Answer 16

(methane) allows short(er)
wavelength radiation to pass
through (from the sun)
(which is) re-emitted from the
surface as long(er) wavelength
radiation
(which is) absorbed (by
methane in the atmosphere)

Question 17

Answer 17

weigh (evaporating) basin / dish
• add measured volume of water
• weigh (evaporating) basin / dish and water
• heat to evaporate water
• reweigh
• repeat heating until constant mass obtained
• subtract mass of (evaporating) basin / dish from mass
• repeat and calculate a mean, discarding anomalous results
• calculate the mass in 100 cm° water if necessary

Question 18

Answer 18

(polyester is) thermosoftening
(polyester has) no cross-links

Question 19

Answer 19

Question 20

Answer 20

Question 21

Answer 21

wood is renewable or
(natural) gas is finite
(burning) wood produces the same amount of carbon dioxide as the trees absorbed or
(burning natural) gas increases the amount of carbon dioxide in the atmosphere

Question 22

Answer 22

(rate) decreases
3.4
(rate decreases) more slowly as time increases
(rate) becomes zero at 60 s

Question 23

Answer 23

• (too) viscous
• not (very) flammable
• boiling point (too) high

Question 24

Answer 24

.sunshine is unreliable
• increased demand for energy
• lack of space

Question 25

Answer 25

the boiling point is lower than 0 (°C)

Question 26

Answer 26

Method
• draw (pencil) start line on (chromatography) paper
• place spot of food colouring on start line
• use of suitable solvent
• place solvent in beaker / container
• place (chromatography) paper in beaker / container
• so (chromatography) paper is in solvent
• but solvent is below start line
• use a lid
• wait for solvent to travel up the (chromatography) paper (until near top)
• mark solvent front
• dry the (chromatography) paper
Measurements
• measure distance between start line and centre of spot
• measure distance between start line and solvent front
• use of measurements to determine R value

Question 27

.

Answer 27

(in HDPE) polymer chains are closer together
(so) more atoms per unit volume

Question 28

Answer 28

H2O
HCL

Question 29

Answer 29

ammonium phosphate
potassium nitrate

(nitric acid) calcium nitrate
(phosphoric acid)
(calcium) triple superphosphate

Question 30

Answer 30

(industrial process)
(is) large(er) scale
(is) quicker
(is a) continuous process
reasoned judgement

Question 31

Answer 31

Question 32

Answer 32

grow plants (on land containing copper ores)
allow named plant
plants are burnt (to produce ash)
ash dissolved in acid (to produce a solution of a copper compound)
electrolysis of solution (containing a copper compound)

Question 33

Answer 33

Rate
• higher temperature gives higher rate
• because more frequent collisions
• higher pressure gives higher rate
• because more frequent collisions
• a catalyst can be used to give a higher rate
• because the activation energy is reduced
Yield
• higher temperature gives lower yield
• because the reaction is exothermic
• higher pressure gives higher yield
• because there are more molecules on left hand side
Other factors
• higher temperatures use more energy so costs increase
• higher pressures use more energy so costs increase
• higher pressures require stronger reaction vessels so costs increase
Compromise
• chosen temperature is a compromise between rate and yield
• chosen temperature is a compromise between rate and cost (of energy used)
• chosen pressure is a compromise between rate and cost (of energy used)
• chosen pressure is a compromise between yield and cost (of energy used)

Question 34