Bonding and Limestone Questions

Transcription

1 Bonding and Limestone Questions 56 minutes 56 marks Page of 26

2 Q. Sodium is a reactive element. (a) Complete the diagram to show the electronic structure of a sodium atom. (2) (b) Sodium reacts with chlorine to form sodium chloride. Explain how in terms of electrons, atoms and ions. (4) (Total 6 marks) Page 2 of 26

3 Q2. Aluminium has many uses. (a) An aluminium atom has 3 electrons. (i) Draw the electronic structure of an aluminium atom. () Name the two sub-atomic particles in the nucleus of an aluminium atom.... and... () (iii) Why is there no overall electrical charge on an aluminium atom? () (b) Rail tracks are made from steel. Molten iron is used to weld rail tracks. The reaction of aluminium with iron oxide is used to produce molten iron. (i) Balance the chemical equation for the reaction. () Why does aluminium react with iron oxide? () (Total 5 marks) Page 3 of 26

4 Q3. (a) Sulphur is a yellow element. It is a non-metal. (i) Complete the sentence. In an element, all the atoms..... () Give two properties you would expect sulphur to have because it is a non-metal (2) (b) Use the names of metals from the box to complete the table. copper iron magnesium manganese zinc Use Name of metal for electric wiring in a house... for manhole covers... to galvanise iron... (3) (c) Copper is used to make hot water pipes. Both iron and steel are cheaper. Suggest two reasons why copper is used rather than iron or steel (2) Page 4 of 26

5 (d) The drawing shows a container of a compound called sodium chloride. (i) Which other element has combined with sodium to form this compound?.. () For every atom of sodium, how many atoms of the other element have combined with it?.. () (Total 0 marks) Q4. Choose words from this list to complete the sentences below. carbonate chloride compound mixture oxide solution (a) When two elements react, the new substance formed is called a.... () (b) The white powder formed when zinc reacts with oxygen is called zinc.... () (Total 2 marks) Page 5 of 26

6 Q5. The hip joint sometimes has to be replaced. Early replacement hip joints were made from stainless steel. Stainless steel is an alloy of iron, chromium and nickel. The diagram below represents the particles in stainless steel. Paticle diagram of stainless steal (a) Use the diagram to complete the percentages of metals in this stainless steel. The first one has been done for you. Element Percentage (%) Iron, Fe 72 Chromium, Cr Nickel, Ni (2) (b) Pure iron is a soft, metallic element. (i) Why is iron described as an element? () Page 6 of 26

7 Pure iron would not be suitable for a replacement hip joint. Suggest why. () (iii) The three metals in stainless steel have different sized atoms. Stainless steel is harder than pure iron. Explain why. (2) (Total 6 marks) Q6. The diagram shows some of the substances used and produced at a cement works. (a) Limestone is mainly calcium carbonate (CaCO 3 ). Write the correct answer in each box. (i) The formula shows that calcium carbonate (CaCO 3 ) contains different elements. () The total number of atoms in the formula CaCO 3 is. () Page 7 of 26

8 (b) Name one of the substances produced at the cement works that causes atmospheric pollution. State one effect of this atmospheric pollution. Name... Effect... (2) (c) Limestone is used to produce glass bottles. In recent years we have become more aware of the need to recycle glass bottles. Used glass bottles can be recycled if they are put into bottle banks. (i) Suggest two reasons why light bulbs should not be put into bottle banks. 2 (2) New glass bottles can also be produced by heating a mixture of raw materials: Suggest two environmental reasons why we should recycle glass bottles to make new glass bottles (2) (Total 8 marks) Page 8 of 26

9 Q7. Limestone is a rock. Many buildings and statues are made from limestone. The picture shows a limestone quarry. By Thomas Bjørkan (Own work) [CC-BY-SA-3.0], via Wikimedia Commons (a) A company wants to open a limestone quarry. (i) Some local people want the quarry to be opened. Suggest one reason why. () Other local people do not want the quarry to be opened. Suggest one reason why. () (b) Limestone is used to produce other materials. Draw a ring around the correct answer in each box to complete each sentence. CaCO 3 (i) Limestone is mainly made of CuCO 3 ZnCO 3 () Page 9 of 26

10 When limestone is heated it forms a metal oxide and a gas. carbon dioxide. The gas is carbon monoxide. oxygen. () combustion. (iii) This type of reaction is called decomposition. oxidation. () (Total 5 marks) Q8. In a quarry, limestone is blasted into pieces by explosives. The pieces of limestone are taken from the quarry by lorries. (a) Draw a ring around the correct word in the box to complete the sentence. building Limestone can be used as a plastic material. smart () Page 0 of 26

11 (b) Tick ( ) one possible advantage for people who live near to the limestone quarry. Advantage Tick ( ) causes more traffic provides jobs attracts tourists to the area () (c) Give two types of pollution that would be caused by the limestone quarry (2) (d) Limestone contains calcium carbonate (CaCO 3 ). Complete the two empty boxes in the table about the formula of calcium carbonate. Name of element Symbol for the element Number of atoms in the formula calcium Ca carbon C oxygen (2) (e) Lorries take some of the limestone to be heated in a lime-kiln. Calcium carbonate, in the limestone, decomposes when heated. Use the balanced chemical equation to help you complete the word equation for the decomposition of calcium carbonate. CaCO 3 CaO + CO 2 calcium carbonate... + carbon dioxide () (Total 7 marks) Page of 26

12 Q9. 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 2 Sample 3 Sample 4 A B C D Limestone is a rock containing calcium carbonate, CaCO 3 If the limestone is pure calcium carbonate then the mass of solid remaining would be 2.80 g. Why does the mass of limestone decrease when it is heated? () Page 2 of 26

13 (b) Suggest and explain why the solid remaining was cooled in a dry, argon atmosphere. (2) (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 3 of 26

14 M. (a) mark for electrons shown mark for 2:8: arrangement accept any symbol for electrons (b) max 3 marks if reference to covalent bonding or sharing electrons a sodium atom loses one electron do not accept gains 7 electrons to become sodium / positive ion(s) a chlorine atom gains one electron do not accept loses 7 electrons allow mark for sodium loses electrons and chlorine gains electrons to become chloride / negative ion(s) allow chlorine ion for 2 marks accept: chlorine gains an electron from sodium or chlorine and sodium become ions if no other marks scored allow 2 marks for sodium loses electrons and chlorine gains electrons to form ionic bonds if no other marks scored allow mark for: both sodium and chlorine get full outer shells or reference to ionic bonding [6] M2. (a) (i) any sensible symbol can be used to represent an electron proton(s) and neutron(s) both needed for the mark Page 4 of 26

15 (iii) number of protons is equal to number of electrons allow positive and negative charges cancel out allow same amount of protons and electrons (b) (i) 2 Al + Fe 2 O 3 2 Fe + Al 2 O 3 equation must be balanced aluminium is more reactive (than iron) it = aluminium accept converse accept aluminium displaces iron accept aluminium is higher in the reactivity series (than iron) [5] M3. (a) (i) are identical / the same or have the same number of protons / the same proton number / electrons not similar any two of low melting point low boiling point brittle (solid) do not credit just solid poor conductor of heat or heat insulator poor conductor of electricity or electrical insulator accept just poor / low conductor or just insulator once only dull surface or not shiny cannot be hammered / bent (into shape) or not malleable cannot be stretched (into shape) or not ductile does not make a clanging sound (when struck) or not sonorous acidic oxides low density 2 Page 5 of 26

16 (b) copper iron zinc correct symbols (c) can be bent (easily) or malleable or can be joined easily do not credit just can be joined not reactive or does not corrode or does not react (with hot water) accept does not rust 2 (d) (i) chlorine do not credit chloride one / same number / amount [0] M4. (a) compound (b) oxide [2] M5. (a) (Chromium =) 20 in correct order (Nickel =) 8 accept Chromium = 8 and Nickel = 20 for mark (b) (i) (because iron is made up of only) one type of atom Page 6 of 26

17 not strong allow too soft or too flexible accept it rusts / corrodes or that it could wear away accept could change shape / bend accept layers / atoms could slide (over each other) (iii) structure is different / distorted / disrupted accept not in layers or not regular so it is difficult for layers / atoms / particles to slip / slide (over each other) accept layers cannot slip / slide [6] M6. (a) (i) 3 / three 5 / five (b) carbon dioxide / CO 2 for a correct emission (causes) global warming / climate change / greenhouse gas explanation must be correct for named emission ignore ozone layer or (cement) particles / smoke () (causes) asthma / dust / (global) dimming () accept breathing problems or sulfur dioxide / SO 2 / nitrogen oxides / NO x () (causes) acid rain () do not accept nitrogen or water vapour for emissions do not accept no named emission Page 7 of 26

18 (c) (i) any two from: ignore contamination without explanation contain metals/ filaments / wires accept named metal(s) contain other / toxic chemicals / materials accept named chemical(s) / material(s) different type of glass accept glass would not metl ignore thicker / thinner glass 2 any two from: allow converse arguments low / less energy / heat or lower temperature needed ignore no energy without explanation low / less fuel burned ignore no fuel without explanation accept less fuel for extraction / transportation of raw materials no / less carbon dioxide / global warming / less use of carbonate(s) accept name(s) of this carbonate(s) less landfill ignore less litter less use of resources / raw materials 2 [8] M7. (a) (i) any one from: increases jobs more money in local economy increase in local trade more shops / businesses improved transport links ignore uses of limestone Page 8 of 26

19 (b) (i) CaCO 3 any one from: dust (pollution) ignore smell allow named respiratory problem noise (pollution) ignore pollution unqualified scar on landscape allow reduction in tourism destroys habitats ignore takes up space extra traffic more heavy vehicles carbon dioxide (iii) decomposition [5] M8. (a) building (b) provides jobs Page 9 of 26

20 (c) any two from: ignore references to water noise allow sound pollution dust / visual pollution accept global dimming ignore smoke air / atmospheric exhaust gases accept acid rain / global warming / named gaseous pollutants (more) traffic accept more lorries 2 (d) O ignore any numbers 3 / three (e) calcium oxide accept quicklime do not accept calcium dioxide [7] M9. (a) gas / carbon dioxide / CO 2 (produced / released) ignore how gas is formed (b) 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 2 Page 20 of 26

21 (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 2 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 2 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) amount of waste 7 Wind direction carries dust, noise, fumes etc towards town (only B & D are directly downwind of town) 4 [7] Page 2 of 26

22 E. (a) It was pleasing to note that the majority of students could correctly complete the diagram of the electronic structure. Where mistakes were made in the configuration, one mark was awarded for showing electrons. (b) The formation of sodium chloride was less well understood with less than a tenth of students able to gain three or four marks. To gain full marks it was necessary only to state that a sodium atom loses an electron to become a sodium ion and that a chlorine atom gains an electron to become a chloride ion. Many students stated that seven electrons were transferred. There were frequent references to the sharing of electrons. Few students realised that losing an electron results in a positively charged ion and vice versa. E2. (a) (i) This was well answered. Several students adopted an excellent strategy of writing out the structure as 2, 8, 3 and then drawing the diagram. Most students used dots or crosses to represent the electrons. Some students changed their minds and over-wrote their original answer; so at times it was difficult to tell whether an electron had been crossed out or not. The most common errors were putting more than 2 electrons in the first shell or fewer than 8 in the second shell. (iii) The names of the two sub-atomic particles in the nucleus were well known. The most common error was to include electron and, occasionally, nucleus. Only a minority of students answered this correctly. Several students were confused about the names and the charges on sub-atomic particles. Others incorrectly thought that the overall electrical charge was related to the number of electrons in the outer shell. (b) (i) This question was well done with only a few students giving an incorrect answer or not providing an answer. A few put symbols or formulae on the dotted lines, suggesting that they do not know what is meant by balancing a chemical equation. A majority of students did not understand why aluminium reacts with iron oxide. A substantial number of students did not appreciate that the reactivity series relates to the reactivity of metals not compounds. Others attempted unsuccessfully to answer in terms of electrons. E3. Except for part (b) this chemistry question was, in general, poorly answered. Many candidates appeared not to know the meaning of the word property and even fewer knew the specific properties of non-metals and ionic compounds. Some made muddled references to atomic structure. In part (c), many suggested that copper is used for hot water pipes in preference to steel because it is cheaper (even though they had just been told that steel is cheaper), or that it is a conductor. Page 22 of 26

23 E4. Paper 2 Option P This question was generally well answered. Paper 4 Option Q This question was well answered. E5. (a) The majority of students correctly calculated the percentages of chromium and nickel in stainless steel. (b) (i) Surprisingly a large number of students could not define an element. (iii) A large majority of students knew that the softness of pure metal made it unsuitable for a replacement hip joint. Surprisingly most students could not explain, in terms of structure, why stainless steel is harder than pure iron. E6. (a) (i) Most students realised that there were three different elements in calcium carbonate. Most students did not realise that there were five different atoms in the formula of calcium carbonate. (b) Most answers had correctly identified a cause of atmospheric pollution and usually linked it to the correct effect. (c) (i) The majority of students realised that there was metal in a light bulb, although very few could give a correct second reason. Most students were able to give one environmental reason for recycling glass bottles to make new glass bottles, although very few could give a correct second reason. Page 23 of 26

24 E7. (a) (i) Many students said the quarry would provide more jobs or increase trade. Uses of limestone were often mentioned but ignored, as were references to the quarry being a tourist attraction. Most correct responses mentioned noise or dust pollution. Many students just said the quarry would cause pollution, which was too vague. A specific example had to be given. (b) (i) The majority of students selected the correct formula for limestone. (iii) Approximately, equal numbers of students selected either carbon dioxide or carbon monoxide as one of the products formed when limestone is heated. Few gave oxygen as the answer. A fifth of students thought heating limestone is an oxidation reaction. The remaining students were roughly split between selecting combustion or decomposition. E8. (a) The majority of candidates knew that limestone could be used as a building material. (b) (c) (d) (e) The majority of candidates were able to identify that one possible advantage for the people who lived near to the limestone quarry was that it could provide jobs. Many candidates just stated environmental pollution or emissions without giving the type of environmental pollution or the type of emission. However, most candidates did score two marks here. The most popular correct answers were dust, noise and pollution caused by carbon dioxide in exhaust gases. Most candidates correctly gave O as the symbol for oxygen. The number of oxygen atoms in the formula CaCO 3 was often stated incorrectly as being two. Most candidates correctly gave calcium oxide as the compound with the formula CaO. A few candidates thought incorrectly that the name of the compound was calcium oxygen. Page 24 of 26

25 E9. (a) In the final question it was good to see carbon dioxide named as the cause of the loss of mass. Quite a few candidates seemed to think incorrectly that the loss in mass was caused by the heat driving off the impurities or the moisture in the limestone. (b) (c) This part proved to be difficult for most candidates. Many thought that the calcium oxide would react with oxygen rather than with water vapour or carbon dioxide in the air. Several candidates scored zero because they selected one site but went on to write about a different site. A few good accounts failed to score full marks as they contained all advantages and no disadvantages. Many candidates listed points straight from the map, such as near the road or near the river without explaining why these are advantages or disadvantages. A common misunderstanding was that the heavier the mass of solid remaining after heating, the more limestone you were getting. All sites would be noisy, destroy an area of beauty and cause dust. The question is why some sites would be more acceptable than others. The mark scheme allowed any chosen site to gain all four marks. Page 25 of 26

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