Q1. The diagram shows a small part of the structure of silicon dioxide. Draw a ring around the correct answer to complete each sentence.

Transcription

1 Q. The diagram shows a small part of the structure of silicon dioxide. (a) Use the diagram above to answer the question. Draw a ring around the correct answer to complete each sentence. In silicon dioxide, each silicon atom is bonded with three oxygen atoms. two four ionic. The bonds in silicon dioxide are covalent. metallic. (2) (b) Oleksiy Mark/iStock Silicon dioxide is used as the inside layer of furnaces. Suggest why. () Page of 36

2 (c) Nanowires can be made from silicon dioxide. Draw a ring around the correct answer to complete the sentence. brittle. The word nano means the wires are very thick. thin. () (Total 4 marks) Q2. The picture shows a student filling in a multiple choice answer sheet using a pencil. Cihan Ta?k?n/iStock The pencil contains graphite. Graphite rubs off the pencil onto the paper. Diagrams and 2 show how the atoms are arranged in graphite. (a) Use the diagrams to help you explain why graphite can rub off the pencil onto the paper. Page 2 of 36

3 (2) (b) Draw a ring around the type of bond which holds the atoms together in each layer. covalent ionic metallic () (Total 3 marks) Q3. This question is about lithium and sodium. (a) Use the Chemistry Data Sheet to help you to answer this question. In which group of the periodic table are lithium and sodium? Group () (b) A lithium atom can be represented as The diagram represents the lithium atom. (i) Some particles in the nucleus have a positive charge. What is the name of these particles?... () (ii) Some particles in the nucleus have no charge. What is the name of these particles?... () (iii) Use the correct answer from the box to complete the sentence The mass number of this atom of lithium is () Page 3 of 36

4 (c) Sodium reacts with chlorine to produce sodium chloride. sodium + chlorine sodium chloride The diagram shows how the reaction happens. Only the outer electrons are shown. Draw a ring around the correct answer to complete each sentence. gaining (i) A sodium atom changes into a sodium ion by losing an electron. sharing () a negative (ii) A sodium ion has no charge. a positive () (iii) The ions in sodium chloride are held together by strong covalent electrostatic forces. magnetic () (d) Sodium chloride is an ionic compound. Tick ( ) two properties of ionic compounds. Property Tick ( ) Do not dissolve in water High melting points Low boiling points Strong bonds (2) Page 4 of 36

5 (e) (i) The formula of sodium chloride is NaCl Calculate the relative formula mass of sodium chloride. Relative atomic masses: Na = 23; Cl = Relative formula mass =... () (ii) Draw a ring around the correct answer to complete each sentence. The relative formula mass of a substance, in grams, is one ion isotope mole of the substance. () (f) Nanoparticles of sodium chloride (salt) are used to flavour crisps. What are nanoparticles? () (Total 2 marks) Page 5 of 36

6 Q4. Silicon dioxide is used as a lining for furnaces. Furnaces can be used to melt iron for recycling. Oleksiy Mark/iStock The diagram shows a small part of the structure of silicon dioxide. Explain why silicon dioxide is a suitable material for lining furnaces (Total 4 marks) Page 6 of 36

7 Q5. Oil rigs are used to drill for crude oil. Digital Vision/Photodisc (a) Drills are made from an alloy of iron. The diagrams show the particles in the alloy and in pure iron. Use the diagrams to explain why the alloy is harder than pure iron. (2) (b) Drill heads contain diamonds. Tick ( ) two reasons why diamonds are hard. Reason Tick ( ) Diamonds have a giant covalent structure. Diamonds have high melting points. Diamonds are unreactive. Diamonds have strong bonds between carbon atoms. (2) Page 7 of 36

8 (c) Methane gas is often found where crude oil is found. The diagram shows how atoms bond in methane. Only the outer electrons are shown. (i) Draw a ring around the correct answer to complete the sentence. a compound. Methane is an element. a mixture. () (ii) Draw a ring around the correct answer to complete each sentence. C 4 H 4 The formula of methane is C 4 H CH 4 () (iii) Name the type of bond between the carbon and hydrogen atoms in methane.... () (d) Explain why methane is a gas at 20 C. (2) (Total 9 marks) Page 8 of 36

9 Q6. This question is about the planet Mars. Tristan3D/Shutterstock (a) Mars is a red colour in the sky at night. The red colour of Mars is because of iron oxide. Iron oxide is an ionic compound. Draw a ring around the correct answer to complete each sentence. giant lattices. Ionic compounds are made of polymer chains. simple molecules. () (b) Many spacecraft have been sent to Mars. Parts of these spacecraft are made from polymers. (i) Polymers that behave like shape memory alloys are used in spacecraft. The shape memory polymers are cooled and compressed. These polymers are stored on the spacecraft until needed. Suggest how the polymers could be made to return to their original shape. () Page 9 of 36

10 (ii) Thermosetting polymers are used for the tiles on the outside of spacecraft. The diagram shows the structure of a thermosetting polymer. Explain, in terms of structure, why some polymers are thermosetting. (2) (c) Instrumental methods such as GC MS are used to analyse substances found on Mars. In GC MS, gas chromatography columns are linked to mass spectrometers. (i) What does gas chromatography do to the substances? () (ii) Give two reasons for using instrumental methods for analysis. 2 (2) (Total 7 marks) Page 0 of 36

11 Q7. Scientists have recently developed a method to produce large sheets of a substance called graphene. Graphene is made from carbon and is a single layer of graphite just one atom thick. The properties of graphene include: it conducts electricity it is transparent since it is only one atom thick it is strong and durable. These properties make it suitable to overlay a monitor screen to make it a touchscreen. The photograph below shows the structure of graphene. Photographs supplied by istockphoto/thinkstock Use your knowledge of the bonding in graphite and the photograph of the structure to help you to explain, as fully as you can: (a) (i) why graphene is strong; (3) Page of 36

12 (ii) why graphene conducts electricity. (2) (b) Suggest why a sheet of graphite which has a large number of carbon layers would not be suitable for the touchscreen. () (Total 6 marks) Q8. Pure carbon can exist in two forms, diamond and graphite. (a) Complete the diagram to show the electronic structure of a carbon atom. A carbon atom has 6 electrons. Show the electrons as crosses (x). () Page 2 of 36

13 (b) A drill bit is used to cut holes through materials. The cutting end of this drill bit is covered with very small diamonds. By Wanderlinse [CC By 2.0], via Flickr (i) What property of diamond makes it suitable for use on the cutting end of a drill bit? () (ii) Explain, as fully as you can, why diamond has this property. Use your knowledge of the structure and bonding of diamond and the information shown opposite to help you to answer this question. (3) Page 3 of 36

14 (c) Explain why graphite is a good conductor of electricity and why diamond does not conduct electricity. (3) (Total 8 marks) Page 4 of 36

15 Q9. The picture shows a copper kettle being heated on a camping stove. Copper is a good material for making a kettle because: it has a high melting point it is a very good conductor of heat. (a) Explain why copper, like many other metals, has a high melting point. Your answer should describe the structure and bonding of a metal. (4) Page 5 of 36

16 (b) Aeroplanes contain many miles of electrical wiring made from copper. This adds to the mass of the aeroplane. It has been suggested that the electrical wiring made from copper could be replaced by carbon nanotubes which are less dense than copper. The diagram shows the structure of a carbon nanotube. (i) What does the term nano tell you about the carbon nanotubes? () (ii) Like graphite, each carbon atom in the carbon nanotube is joined to three other carbon atoms. Explain why the carbon nanotube can conduct electricity. (2) (Total 7 marks) Page 6 of 36

17 Q0. Spacecraft have been to the planets Venus and Mars. The spacecraft have sent back information about the atmosphere of each planet. Tristan3D/Shutterstock (a) The main gas in the atmosphere of Mars is carbon dioxide. Explain why, in terms of structure, carbon dioxide is a gas, even at low temperatures. (3) (b) Gas chromatography linked to a mass spectrometer (GC-MS) is used to identify substances found on Mars. (i) What is the purpose of gas chromatography? () (ii) What information do the molecular ion peaks from the mass spectrometer give about the substances? () Page 7 of 36

18 (c) The atmosphere on Venus contains droplets of sulfuric acid solution. (i) Suggest a ph value for sulfuric acid solution. ph =... () (ii) Name the ion which makes sulfuric acid solution acidic. () (d) The atmosphere of Venus contains the isotopes and Describe the similarities and the differences in the isotopes and You should refer to the sub-atomic particles in each isotope. (3) (Total 0 marks) Page 8 of 36

19 Q. Read the article and then answer the questions. Nanotennis! Tennis balls contain air under pressure, which gives them their bounce. Normal tennis balls are changed at regular intervals during tennis matches because they slowly lose some of the air. This means that a large number of balls are needed for a tennis tournament. Feng Yu/iStock Nanocoated tennis balls have a nanosize layer of butyl rubber. This layer slows down the escape of air so that the ball does not lose its pressure as quickly. The nanocoated tennis balls last much longer and do not need to be replaced as often. (a) Tick ( ) the best description of a nanosize layer. Description Tick ( ) A layer one atom thick. A layer a few hundred atoms thick. A layer millions of atoms thick. () (b) Suggest two ways in which using nanocoated tennis balls would be good for the environment. (2) (Total 3 marks) Page 9 of 36

20 Q2. Graphite and diamond are different forms of the element carbon. Graphite and diamond have different properties. The structures of graphite and diamond are shown below. Graphite Diamond (a) Graphite is softer than diamond. Explain why. (4) (b) Graphite conducts electricity, but diamond does not. Explain why. (3) (Total 7 marks) Page 20 of 36

21 Q3. Read the information Graphene Scientists have made a new substance called graphene. The bonding and structure of graphene are similar to graphite. Graphene is made of a single layer of the same atoms as graphite. Graphene Graphite Use the information above and your knowledge of graphite to answer the questions. (a) This part of the question is about graphene. Choose the correct answer to complete each sentence. (i) ionic covalent metallic The bonds between the atoms in graphene are... () (ii) chromium carbon chlorine Graphene is made of... atoms. () (iii) In graphene each atom bonds to... other atoms. () Page 2 of 36

22 (b) This part of the question is about graphite. Graphite is used in pencils. Explain why. Use the diagrams to help you. (2) (Total 5 marks) Q4. This drinks bottle is made of thermosoftening plastic. Drinks bottles of this type can be recycled. Describe and explain how the bottles can be changed into new plastic objects (Total 4 marks) Page 22 of 36

23 Q5. Oil rigs are used to drill for crude oil. Digital Vision/Photodisc (a) Drill heads are made from steel. Steel is an alloy. Explain why alloys are harder than pure metals. (3) (b) Drill heads also contain diamonds. Describe, as fully as you can, the structure and bonding in diamond. (4) Page 23 of 36

24 (c) Polymers are produced from crude oil. Describe the structure and bonding in a thermosoftening polymer and explain why thermosoftening polymers melt when heated. (4) (Total marks) Page 24 of 36

25 M. (a) four covalent (b) because it has a high melting point accept it won t melt accept it won t decompose or react allow withstand high temperatures ignore boiling point (c) thin [4] M2. (a) layers which have weak forces / attractions / bonds between them second mark must be linked to layers or which can slide over each other or separate ignore references to rubbing (b) covalent [3] M3. (a) / one (b) (i) protons (ii) neutrons (iii) 7 (c) (i) losing (ii) a positive (iii) electrostatic Page 25 of 36

26 (d) high melting points strong bonds (e) (i) 58.5 (ii) mole (f) very small (particles) or ignore tiny / small / smaller / microscopic etc. -00nm in size or (particle with a) few hundred atoms [2] M4. high melting point reference to incorrect bonding or incorrect particles or incorrect structure = max 3 accept will not melt (at high temperatures) ignore withstand high temperatures because a lot of energy needed to break bonds because it is covalent or has strong bonds accept bonds are hard to break and because it is a giant structure or a macromolecule or a lattice ignore many bonds [4] M5. (a) (alloy) atoms / ions / particles not in layers accept layers are distorted accept different (size) particles / atoms so, (alloy) layers / atoms / ions / particles can t slide if no other mark awarded allow (an alloy) is a mixture of metals for mark (b) diamonds have a giant covalent structure Page 26 of 36

27 diamonds have strong bonds between carbon atoms (c) (i) a compound (ii) CH 4 (iii) covalent (d) methane has a low boiling point or boiling point less than 20 C molecules because it has small molecules accept it has forces between molecules accept weak forces between molecules for 2 marks [9] M6. (a) giant lattices (b) (i) heat / warm / increase the temperature allow reduce pressure do not accept melt (ii) (polymer) chains cannot slide because they have cross-links if no other mark awarded allow polymers do not melt for mark (c) (i) separates (substances) (ii) any two from: ignore reliable / precise / efficient ignore references to cost quick / rapid accurate can detect small quantities / sensitive 2 [7] Page 27 of 36

28 M7. (a) (i) ionic / molecules / metallic / (inter)molecular = max 2 because graphene / it has a giant structure / lattice / macromolecular accept all / every / each atom is bonded to 3 other atoms because graphene / it has covalent bonds / is covalent because in graphene / the bonds are strong or a lot of energy needed / hard to break the bonds (ii) there are delocalised / free electrons because one (delocalised / free) electron per atom linked to first marking point accept because three electrons per atom used (in bonding) accept because one electron per atom not used (in bonding) (b) opaque (owtte) eg could not see through them or layers slide or layers not aligned ignore thick [6] M8. (a) 2,4 (drawn as crosses) on shells accept dots / e / - etc. (b) (i) hard allow rigid / high melting point do not allow references to bonding ignore strong ignore unreactive ignore structure Page 28 of 36

29 (ii) any three from max 2 if ionic / metallic / molecule / intermolecular bonds or incorrect number of bonds giant structure / lattice / macromolecular allow many bonds covalent (bonds) (covalent) bonds are strong accept needs lots of energy to break bonds (owtte) (each) carbon / atom forms four bonds or (each) carbon / atom bonded to four other atoms 3 Page 29 of 36

30 (c) any three from: max 2 if ionic / ions / metallic / molecule it needs to be qualified graphite has delocalised / free electrons do not accept the electrons move unless qualified (around structure etc) or electrons that can move through / around the structure each carbon is joined to three other carbon atoms allow graphite has three bonds or diamond one electron from each atom is free / delocalised has no free / delocalised electrons do not accept the electrons do not move or no electrons that move around the structure all the electrons are used for bonding allow diamond has 4 bonds or each carbon joined to four other carbon atoms 3 [8] M9. (a) reference to incorrect bonding or incorrect structure or incorrect particles = max 3 giant structure / lattice ignore many bonds made up of positive ions surrounded by delocalized / free electrons allow positive ions surrounded by a sea of electons with strong bonds / attractions allow hard to break for strong Page 30 of 36

31 so a lot of energy is needed to break these bonds / attractions / forces ignore high temperature ignore heat (b) (i) that they are very small or -00 nanometres or a few(hundred) atoms accept tiny / really small / a lot smaller / any indication of very small eg. microscopic, smaller than the eye can see ignore incorrect numerical values if very small is given (ii) delocalised / free electrons allow sea of electrons one non-bonded electron from each atom accept electron(s) moving through the structure / nanotube allow electron(s) carry / form / pass current / charge [7] M0. (a) has simple / small molecules accept molecular covalent the intermolecular forces / intermolecular bonds (are weak) do not accept weak covalent bonds or reference to incorrect bonding only need a small amount of energy to be overcome accept only need a small amount of energy to separate the molecules if no other mark awarded, allow it has a low boiling point for mark (b) (i) to separate (ii) (relative) molecular mass allow M r / (R)MM / relative mass / mass of molecule / (R)FM (c) (i) any ph value from 0 to 6.9 Page 3 of 36

32 (ii) hydrogen allow H + ignore H / H 2 / H (d) any three from: same number of protons accept same atomic number numbers if given must be correct 2 H has one neutron H has no neutrons accept different mass number or different number of neutrons for mark ignore relative atomic mass same number of electrons numbers if given must be correct 3 [0] M. (a) a layer a few hundred atoms thick (b) any two from: any two ideas less materials or save resources less energy less fuel less pollution / greenhouse effect / global warming less waste ignore references to cost / recycling 2 [3] M2. (a) Graphite: because the layers (of carbon atoms) in graphite can move / slide it = graphite this is because there are only weak intermolecular forces or weak forces between layers accept Van der Waals forces allow no covalent bonds between layers Page 32 of 36

33 Diamond: however, in diamond, each carbon atom is (strongly / covalently) bonded to 4 others allow diamond has three dimensional / tetrahedral structure so no carbon / atoms able to move / slide allow so no layers to slide or so diamond is rigid (b) because graphite has delocalised electrons / sea of electrons allow free / mobile / roaming electrons which can carry charge / current or move through the structure however, diamond has no delocalised electrons accept however, diamond has all (outer) electrons used in bonding [7] M3. (a) (i) covalent two different answers indicated gains 0 marks (ii) carbon two different answers indicated gains 0 marks (iii) 3 two different answers indicated gains 0 marks (b) layers can slide / slip because there are no bonds between layers accept because weak forces / bonds between layers or so (pieces of) graphite rubs / breaks off or graphite left on the paper [5] Page 33 of 36

34 M4. heat then mould / extrude into a new shape / object plastic made of polymer chains that can move (when heated) because plastic / polymer has weak intermolecular forces [4] M5. (a) because atoms / ions / particles in alloy are different (sizes) do not allow reference to molecules ignore reference to compounds so layers distorted (and layers / atoms / ions / particles) don t slide or slide less easily accept all marking points in a suitably labelled or annotated diagram if no other mark awarded accept an alloy is a mixture or contains different metals / elements for mark (b) giant structure or lattice or macromolecule max 3 marks if incorrect bonding strong bonds (between carbon / atoms) covalent (bonds) each carbon / atom forms 4 bonds accept tetrahedral if no other marks awarded, allow carbon (atoms) for mark (c) reference to incorrect bonding = max 3 reference to weak covalent bonds = max 2 allow correctly drawn diagram for first two marking points eg. (tangled) lines with no cross-links chains or large molecules ignore layers Page 34 of 36

35 with intermolecular forces or forces between chains allow bonds for forces accept no cross-links that are weak must relate to 2 nd marking point and are easily overcome/ broken (when heated) accept molecules / chains can flow / move [] Page 35 of 36

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