Q1. Bags of readi-to-mix concrete contain three ingredients. Complete each sentence by choosing the correct words from the box. Cement is made by heating.......................................... and ......................................... in a rotary kiln. To make concrete, the contents of the bag of readi-to-mix concrete must be mixed with ............................................................................... . (Total 3 marks) Readi-to-mix Concrete contains cement crushed rock sand clay limestone salt slaked lime water Page 1 of 24
Transcript
Q1. Bags of readi-to-mix concrete contain three ingredients.
Complete each sentence by choosing the correct words from the box.
Cement is made by heating.......................................... and ......................................... in a rotary kiln.
To make concrete, the contents of the bag of readi-to-mix concrete must be mixed with
Draw a ring around the correct gas in the box to complete the sentence.
(1)
The gas formed when calcium carbonate decomposes is
argon.
carbon dioxide.
nitrogen.
(c) The cement works starts to burn a different fuel.
Local residents are concerned because more children are suffering asthma attacks. Residents have also noticed that parked cars are becoming dirty because of smoke particles from the chimney.
The table shows the possible medical risk from smoke particles.
Particle size in mm Medical effect
Larger than 0.4 No medical risks known
0.3 and smaller Causes asthma attacks
0.2 and smaller May cause cancer
(i) Give two reasons why local residents are concerned about the cement works burning a different fuel.
(d) (i) Quicklime (calcium oxide) can be converted to slaked lime (calcium hydroxide) by adding water. Write a word equation to represent this reaction.
accept natural gas ignore air do not allow other gases
1
(ii) carbon dioxide 1
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(c) (i) any two from:
• medical risks
• asthma
• cancer
• dirt
• causes global warming / global dimming / greenhouse effect / acid rain ignore death accept effect on health accept difficulty breathing/ lung disease allow smoke particles allow harmful for the environment
2
(ii) any two from:
• have a test done / scientific evidence
• independent (evidence)
• comparison of smoke particles / when different fuels used
• medical evidence or more / less asthma attacks or cancer or dirt on cars
2 [10]
M4. (a) calcium oxide 1
calcium hydroxide 1
calcium carbonate 1
substances must be in the order shown
(b) (i) strength of mortar decreases (as volume of sand increases) 1
(ii) 400 (cm3)
1
because the height_ the metal ball dropped from should be 42 cm and not 37 cm
accept because the other results show that the height_ the metal ball dropped from should have an interval of 6cm
1
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(c) contains aggregate allow bonding is stronger
1 [7]
M5. (a) calcium carbonate
not formula 1
(b) calcium carbonate → calcium oxide not common names allow correct formulae
1
+ carbon dioxide 1
(c) calcium hydroxide not formula
1
(d) CaO + H2O → Ca(OH)
2
allow if doubled
all formulae correct, no extra ones 1
balanced 1
(e) filtration allow centrifugation
not decanting not evaporation, crystallisation
1
(f) electrolysis stated or implied
molten MgO / magnesium oxide is ionic / Mg2+ goes to cathode
not just heated 1
or add sodium / K / Ca / Li / a more reactive metal 1
displaces Mg / reduces Mg give no marks if reference made to reduction by C or H
1 [9]
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M6. (a) any two from:
• nitrogen accept formulae N / N
2
• carbon dioxide accept formula CO
2
ignore CO
• water (vapour) / steam accept formula H
2O
2
(b) any three from:
no mark for ‘limestone’ or ‘concrete’ on first line – mark advantages only
limestone
• abundant / local ignore ideas of speed of production or easier to use
• natural material or no ‘processing’ needed
• relatively easy to cut
• appearance better
concrete
• raw materials are abundant
• can be reinforced (by steel rods) / strong(er) / supported (by steel rods) accept ‘can build higher’
• concrete mixture can be poured / moulded / constructed on site
• less reactive with acid rain / weathering / erosion ignore density / extraction / quarrying / pollution / cost
3 [5]
##
from limestone/marble; from calcium carbonate; action of heat/thermal decomposition; (other product is) carbon dioxide
any three for 1 mark each [3]
-
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M8. (a) (i) calcium oxide / quicklime
allow calcium monoxide do not accept calcium dioxide ignore chemical formulae
1
(ii) any three from:
• carbon dioxide / CO2
• (carbon dioxide) reacts (with the calcium hydroxide / slaked lime / plaster) allow reaction 3 identified do not allow incorrect reaction ignore mixes, unless they state the correct product
• limestone / calcium carbonate / CaCO3 forms
allow marble / chalk
• water is lost / evaporates it = plaster allow moisture ignore dries
3
(b) (i) as the amount / volume of sand decreases the strength of the mortar increases
accept as sand decreases the mortar is stronger / harder to crack allow as sand decreases the mortar increases allow converse ignore references to height_ of metal ball
1
(ii) any two from:
• 400 / 5th result is anomalous
accept two results (36 and 37 / 400 and 500 / 4th and 5th) are almost the same accept result at 400 should be 42
• the interval between the others is similar or the interval is about 6/7 allow the other results fit a pattern / are on a straight line
• he has only one set of results allow he has only done it once ignore reliable
2 [7]
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M9. (a) calcium carbon oxygen
2 correct for 1 mark 3 correct for 2 marks
2
(b) cement glass
each for 1 mark 2
(c) (i) allows coal to bum / flushes out CO2
for 1 mark 1
(ii) produced by burning coal produced by decomposition of limestone
each for 1 mark 2
(d) (i) calcium oxide + water → calcium hydroxide or quicklime + water → slaked lime
for 1 mark (allow composite equation from these two)
1
(ii) to neutralise it / because it is alkaline or basic for 1 mark
1 [9]
M10. (i) (hot air) gives faster reaction makes coal burn faster (provides air / oxygen to help to) allow the coal to burn / helps combustion flushes out the waste / gases / carbon dioxide
any one for 1 mark 1
(ii) decomposition of limestone yields carbon dioxide (owtte) the combustion / burning of coal produces carbon dioxide (owtte)
each for 1 mark 2
[3]
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M11. (a) (i) heat (the limestone)
accept decompose limestone accept heat with coke
1
add water / slake
dependent on 1st mark unless they say add water to the calcium oxide
1
(ii) magnesium hydroxide + hydrochloric acid
1
→ magnesium chloride + water / H2O
1 mark for each side of the equation (if a symbol equation is given then give 1 mark for correct formulae (all) and 1 mark for balancing)
