C. LIMESTONE AND BUILDING MATERIALS Q. Calcium carbonate is found in limestone. Limestone is used as a building material. Limestone is also used to make calcium oxide and calcium hydroxide. (a) Limestone is heated to make calcium oxide. (i) Calcium oxide reacts with a substance to produce calcium hydroxide. Name the substance. () Calcium hydroxide reacts with a substance to produce calcium carbonate. Name the substance. () Limestone reacts with acids. (i) Balance the chemical equation for the reaction of calcium carbonate with hydrochloric acid. CaCO 3 + HCl CaCl + CO + H O () Buildings made from limestone are affected by the products from burning fossil fuels containing sulfur. Explain why. Page
(c) When a mixture of limestone and clay is heated in a rotary kiln cement is produced. Burning a mixture of methane and air heats the kiln. Clay does not decompose in the kiln. (i) Carbon dioxide is one of the main gases in the mixture of gases coming out of the kiln. Give two reasons why. Name the other main gas in the mixture of gases coming out of the kiln. Give a reason why there is a high percentage of this gas in the mixture of gases coming out of the kiln. Name of gas... Reason... (Total 9 marks) Page
Q. Limestone is mainly calcium carbonate, CaCO 3 The flow diagram represents how calcium oxide (quicklime) is made when calcium carbonate (limestone) is heated in a lime kiln. (a) (i) How many elements is calcium carbonate, CaCO 3, made from? () The main gases leaving the lime kiln are nitrogen and carbon dioxide. Explain why. (3) Calcium oxide (quicklime) is used in self-heating cans. The diagram shows a self-heating can made to warm baked beans. To warm the baked beans the metal pin is pushed through the seal and foil separator. The foil separator breaks allowing water to mix with the calcium oxide (quicklime). Describe what happens when water mixes with calcium oxide. Page 3
............ (Total 6 marks) Q3. A company wants to extract limestone from an area of natural beauty. The Government has granted permission for the company to take and analyse samples of limestone. The company selects four sites, A, B, C and D, within the area and takes four samples from each site. (a) The limestone is analysed by: heating 5 g of each sample for 30 minutes allowing the sample to cool in a dry, argon atmosphere weighing the solid remaining The table shows the company s results. Site Mass of solid remaining in g Sample Sample Sample 3 Sample 4 A 3.5 3.0 3.0 3.9 B 3.5 3. 3.4 3.6 C.85.95.9 3.00 D.98.88.9.8 Page 4
Limestone is a rock containing calcium carbonate, CaCO 3 If the limestone is pure calcium carbonate then the mass of solid remaining would be.80 g. Why does the mass of limestone decrease when it is heated?...... () Suggest and explain why the solid remaining was cooled in a dry, argon atmosphere................ (c) Which site, A, B, C or D, would you choose for extracting limestone? Give the advantages and disadvantages for your chosen site. You must explain why you chose this site. My chosen site is............................... (4) (Total 7 marks) Page 5
Q4. Limestone is an important raw material. (a) The main compound in limestone has the formula CaCO 3. Name the elements in this compound....... 3... Limestone has many uses. Select from the list below two important materials made from limestone. cement diesel oil glass poly(ethene) sodium hydroxide sulphuric acid... and... (c) The diagram shows a lime kiln. The limestone is heated by the burning coal. (i) Suggest why hot air is blown into the lime kiln....... () Page 6
Give two reasons why carbon dioxide is produced in the lime kiln. Reason...... Reason...... (d) (i) Quicklime (calcium oxide) can be converted to slaked lime (calcium hydroxide) by adding water. Write a word equation to represent this reaction.... +...... () Why do farmers sometimes add slaked lime to acidic soil?...... () (Total 9 marks) Q5.Limestone contains calcium carbonate (CaCO 3). (a) Name the type of reaction that takes place when calcium carbonate is heated strongly. Name the products formed................... (3) A student investigated what happens when limestone is heated strongly. This is the method the student used: measure the mass of limestone before heating measure the mass of solid product after heating repeat the experiment three more times. The student s results are shown in the table below. Page 7
Experiment Experiment Experiment 3 Experiment 4 Mass of limestone before heating in g Mass of solid product after heating in g 5.0 5.0 5.0 5.0 3. 4.0 3. 3.3 Mass lost in g.8.0.9.7 (i) Calculate the mean mass lost, taking account of any anomalies. Mean mass lost =... g The student used the chemical equation to calculate the maximum mass lost by 5.0 g of calcium carbonate when heated. The maximum mass lost is. g. Suggest and explain two reasons why the mean mass lost in the experiments to heat limestone is less than. g. Do not include any reference to weighing errors in your answer. (4) (Total 9 marks) Page 8
M. (a) (i) water accept hydrogen oxide allow H O carbon dioxide allow CO accept any soluble carbonate or carbonic acid (i) CaCO 3 + HCl CaCl + CO + H O because sulfur reacts with oxygen / air to produce sulfur dioxide or sulfur burns to produce sulfur dioxide accept correct equation and (sulfur dioxide) causes acid rain that reacts with/erodes limestone/calcium carbonate ignore wears away (c) (i) it = carbon dioxideignore references to carbon dioxide is in the air because carbon dioxide is produced from burning methane accept correct equation because carbon dioxide is produced from decomposing calcium carbonate/limestone accept correct equation do not accept carbon in calcium carbonate reacting with air nitrogen this is the main gas / 75 80% / of air Page 9
allow there is a lot of this gas in air [9] M. (a) (i) 3 / three nitrogen does not react allow nitrogen is not used up in the reaction carbon dioxide is a product of methane / fuel burning / reacting with oxygen accept oxygen in the air reacts with methane carbon dioxide is a product of calcium carbonate decomposing (to produce calcium oxide) do not allow calcium carbonate reacts with oxygen any two from: water and calcium oxide / quicklime react ignore mix to produce calcium hydroxide / slaked lime energy / heat released / exothermic ignore gets hot/heats up correct word equation = marks [6] M3. (a) gas / carbon dioxide / CO (produced / released) Page 0
ignore how gas is formed any two from: calcium oxide / CaO / quicklime (is the solid) (calcium oxide) reacts with water accept reacts to form calcium hydroxide / calcium carbonate or carbon dioxide argon would not react (c) for full marks: candidates should consider and explain four of the following points: for full marks candidates must have at least one advantage and one disadvantage allow only one advantage / disadvantage for each point but each point could be correctly explained as an advantage and a disadvantage for marks ignore issues common to all sites eg scarring the landscape / area of natural beauty ignore comments about sites other than the one chosen unless a comparison is made Wood / habitats screening / use of wood damage to habitat Town (proximity) - noise / visual / dust pollution / damage / subsidence ignore pollution unless explained 3 Labour force- proximity to site (travelling time / use of fuel / carbon footprint) 4 River - pollution due to nearness 5 Transport (of materials) (nearness to road / railway) 6 Quality of limestone - (best D C A B worst) Page
amount of waste 7 Wind direction carries dust, noise, fumes etc towards town (only B & D are directly downwind of town) 4 [7] M4. (a) calcium carbon oxygen correct for mark 3 correct for marks cement glass each for mark (c) (i) allows coal to bum / flushes out CO for mark produced by burning coal produced by decomposition of limestone each for mark (d) (i) calcium oxide + water calcium hydroxide or quicklime + water slaked lime for mark (allow composite equation from these two) to neutralise it / because it is alkaline or basic for mark [9] Page
M5.(a) (thermal) decomposition accept limestone decomposes allow endothermic (to produce) calcium oxide / CaO or quicklime (to produce) carbon dioxide / CO accept a correct word or chemical equation for the last two marking points (i).8(g) accept correct answer with or without working accept.8 +.9 +.7 3 for mark if no other mark awarded allow mark for.6(g) or any calculation with one error the limestone was not pure (calcium carbonate) or contained impurities so less carbon dioxide was produced the temperature was not high enough allow not heated for long enough so the limestone / calcium carbonate did not fully decompose / react [9] Page 3