C2.1Structure and bonding, C2.2 Structure and properties & C2.3 Atomic Structure - Foundation

Transcription

1 C2.Structure and bonding, C2.2 Structure and properties & C2.3 Atomic Structure - Foundation Q. (a) The diagram represents an atom of nitrogen. (i) Use words from the box to label the diagram. electron neutron nucleus proton (2) Draw a ring around the mass number of this atom () Q2. (a) An atom of aluminium can be represented as shown below. In this atom of aluminium the number of protons is... and the number of neutrons is... (2) Which statement in the table below describes the mass of an electron? Tick ( ) one box. Statement Tick ( ) Electrons have a very small mass compared to protons. Electrons have about the same mass as protons. Electrons are much heavier than protons. Electrons have about the same mass as neutrons. () Page

2 Q3. The diagram represents an atom of beryllium. Use a number from the box to complete each sentence (a) The atomic number (proton number) of this atom is. () The mass number of this atom is. () (Total 2 marks) Q4. Sodium reacts with chlorine. The reaction forms sodium chloride. (a) Use words from the box to answer the questions. compound element hydrocarbon mixture Which word best describes: (i) sodium... sodium chloride?... () () When sodium reacts with chlorine the sodium atoms change into sodium ions. The diagrams below represent a sodium atom and a sodium ion. Page 2

3 Use the diagrams to help you explain how a sodium atom turns into a sodium ion (2) (i) The diagram below represents a chlorine atom. When chlorine reacts with sodium the chlorine forms negative chloride ions. Complete the diagram below to show the outer electrons in a chloride ion (Cl ). () Chloride ions are strongly attracted to sodium ions in sodium chloride. Explain why () Q5. The drawing shows a container of a compound called magnesium chloride. Page 3

4 (i) How many elements are joined together to form magnesium chloride? () Magnesium chloride is an ionic compound. What are the names of its ions?... ions and... ions () (iii) How many negative ions are there in the formula for magnesium chloride? () (iv) Complete the sentence. Ions are atoms, or groups of atoms, which have lost or gained.... () (v) Suggest three properties which magnesium chloride has because it is an ionic compound. Property... Property 2... Property 3... (3) Q6. This question is about giant structures. Diamond, graphite and silicon dioxide all have giant structures. (a) The diagrams show the structures of these three substances. Draw a line from each structure to its name. Page 4

5 (2) Complete the sentences using words from the box. covalent four hard ionic shiny soft three two (i) Diamond, graphite and silicon dioxide have high melting points because all the (iii) (iv) (v) atoms in their structures are joined by strong... bonds. In diamond each atom is joined to... other atoms. Diamond can be used to make cutting tools because it has a rigid structure which makes it very... In graphite each atom is joined to... other atoms. Graphite can be used to make pencils because it has a structure which makes it... () () () () () When a diamond is heated to a high temperature and then placed in pure oxygen it burns. Carbon dioxide is the only product. Name the element in diamond.... () Q7. The diagram represents a particle of methane. Page 5

6 (a) What is the formula of methane?... () Choose a word from the box to answer the question. atom ion molecule Which of the words best describes the methane particle shown in the diagram?... () Choose a word from the box to answer the question. covalent ionic metallic What is the type of bonding shown in the diagram?... () (Total 3 marks) Q8. This barbecue burns propane gas. The diagram represents a propane molecule. (a) What is the formula of propane?... () (i) Draw a ring around the name of the particle represented by the symbols Page 6

7 and in the diagram. electron neutron proton () Draw a ring around the type of bonding that holds the atoms together in a propane molecule. covalent ionic metallic () Under high pressure in the cylinder propane is a liquid. Liquid propane evaporates easily to form a gas when the tap on the cylinder is opened. Draw a ring around the correct answer in each box to explain why propane evaporates easily. Propane has a high low boiling point because it consists of large small molecules. () Q9. This picture shows a sword. The sword is about 3400 years old. It is made of an alloy called bronze. Bronze is made from copper and tin. Bronze made better swords than pure copper. This is because bronze is harder than pure copper. (a) Draw a ring around the correct answer to complete the sentence. metals. An alloy is a mixture of molecules. non-metals. () Pure copper can be quite easily bent out of shape. Which two statements in the table explain why copper can be bent? Tick ( ) two boxes. Copper atoms are arranged in layers. Statements Tick ( ) Page 7

8 Copper atoms are joined by strong covalent bonds. Copper atoms can slide over each other. Copper is made of small molecules. (2) Which one statement in the table explains why bronze is harder than pure copper? Tick ( ) one box. Statements Tick ( ) Copper and tin atoms are the same size. The layers of atoms are distorted in bronze. The copper and tin atoms are joined by strong covalent bonds in bronze. () Q0. Iron is the main structural metal used in the world. (a) The diagram represents the particles in iron, Fe. Draw a ring around the correct word in the box to complete the sentence. Iron is described as an element because all the atoms compounds metals are the same. () Stainless steel is mostly iron. The diagram represents the particles in stainless steel. Use the correct words from the box to Page 8 complete the sentences about alloys.

9 metal mixture molecule polymer smart structure Stainless steel is an alloy because it is a... of iron, chromium and nickel. An alloy is made up of more than one type of.... Stainless steel alloys are harder than iron because the different sized atoms added change the.... An alloy that can return to its original shape after being deformed is called a... alloy. (4) Page 9

10 Q. (a) Read the article about the use of nanoparticles in sun creams. Sun creams Many sun creams use nanoparticles. These sun creams are very good at absorbing radiation, especially ultraviolet radiation. Owing to the particle size, the sun creams spread more easily, cover better and save money because you use less. The new sun creams are also transparent, unlike traditional sun creams which are white. The use of nanoparticles is so successful that they are now used in more than 300 sun cream products. Some sun creams contain nanoparticles of titanium oxide. Normal-sized particles of titanium oxide are safe to put on the skin. It is thought that nanoparticles can pass through the skin and travel around the body more easily than normal-sized particles. It is also thought that nanoparticles might be toxic to some types of cell, such as skin, bone, brain and liver cells. (i) How is the size of nanoparticles different from normal-sized particles of titanium oxide?... () Suggest how the size of nanoparticles might help them to enter the body more easily () Give two advantages of using nanoparticles in sun creams (2) Why might nanoparticles be dangerous inside the body? () (Total 5 marks) Page 0

11 Q2. (a) The diagram represents an atom of nitrogen. Label the diagram. (3) Ammonia has the formula NH 3. It is made from nitrogen and hydrogen. How many atoms are in an ammonia molecule?... () The diagrams show the electron arrangement in nitrogen and hydrogen. Nitrogen Hydrogen Which diagram below, A, B, C or D, represents an ammonia molecule? A B C D Write your answer in the box. Page Diagram () (Total 5 marks)

12 Q3. (a) Every chemical element has a chemical symbol. Choose the correct chemical symbols from the box and complete the three spaces in the table. C Co Cu Fe I Ir Zn Zr Name of element Chemical symbol Copper... Iron... Zinc... (3) Give one use for each of the following metals. You should give a different use for each metal. Copper... Iron... (2) Give three physical properties which metals usually have (3) (d) Metals usually form ionic compounds. Give one property of an ionic compound. () Page 2

13 (e) The diagrams show two different atoms, atom A and atom B. Atom A Atom B (i) Complete the following sentence. For these two atoms to become ions one... would be transferred from atom... to atom.... () Atom A and atom B are from different elements. How can you tell this from their nuclei? () Q4. This question is about fluorine and some of its compounds. (a) The diagram represents a molecule of hydrogen fluoride. Draw a ring around the type of bonding that holds the hydrogen and fluorine atoms together in this molecule. covalent ionic metallic () Page 3

14 Fluorine is made in industry by the electrolysis of a mixture of potassium fluoride and hydrogen fluoride. (i) Use one word from the box to complete the sentence. gas liquid solid To allow electrolysis to take place the mixture of potassium fluoride and hydrogen fluoride must be.... () The mixture of potassium fluoride and hydrogen fluoride contains fluoride ions (F ), hydrogen ions (H + ) and potassium ions (K + ). Use one word from the box to complete the sentence. fluorine hydrogen potassium During electrolysis the element formed at the positive electrode is.... () Q5. Read the article and then answer the questions that follow. Hydrogen fuel for cars? Hydrogen is an excellent fuel. On combustion it reacts with oxygen from the air to release a large amount of energy. The only product of combustion is water which does not cause pollution. Hydrogen gas can be stored under pressure in a cylinder but a leak of the gas could cause an explosion. It has been found that lithium nitride can absorb and then release large volumes of hydrogen. Hydrogen stored in lithium nitride will not explode. The problem is that the rate at which hydrogen is absorbed and then released from normal sized particles of lithium nitride is slow. Recently scientists have made nanosized particles of lithium nitride. The nanosized particles have the advantage that they absorb and release the hydrogen much faster when needed in the fuel cell. (a) Use information from the article to help you to answer these questions. (i) Give two reasons why hydrogen is an excellent fuel (2) Page 4

15 Hydrogen stored in lithium nitride is safer in an accident than a cylinder full of hydrogen gas. State why.... () (iii) What is the advantage of using nanosized particles of lithium nitride instead of normal sized particles for storing hydrogen?... () Lithium nitride is an ionic compound that contains lithium ions (Li + ) and nitride ions (N 3 ). (i) The periodic table on the Data Sheet may help you to answer this question. Which diagram, A, B or C, represents the electronic structure of a lithium atom? Write your answer in the box. Diagram () Tick ( ) the statement which describes how a lithium atom (Li) changes into a lithium ion (Li + ). Statement Tick ( ) A lithium atom loses a neutron. A lithium atom loses an electron. A lithium atom loses a proton. () (iii) The diagram shows the electronic structure of a nitrogen atom. Which diagram, A, B or C, represents the electronic structure of a nitride ion (N 3 Page 5

16 )? Write your answer in the box. Diagram () The equation for the reaction of lithium nitride with hydrogen is: Li 3N + 2H 2 LiNH 2 + 2LiH What does the symbol mean? Draw a ring around your answer. reversible reaction endothermic reaction neutralisation () (d) Draw a ring around the correct answer in each box to complete the sentences. (i) Nanosized particles of lithium nitride will be much larger a little larger much smaller than normal sized particles of lithium nitride. One of the reasons why nanosized particles have different properties () from normal sized particles is that they have a greater density mass surface area than normal sized particles of lithium nitride. () (Total 0 marks) Page 6

17 Q6. This question is about oxygen atoms. (a) (i) Oxygen atoms have 8 electrons. Complete the diagram to represent the arrangement of electrons in an oxygen atom. Use crosses ( ) to represent the electrons. () Name the part of the oxygen atom that is labelled A on the diagram.... () Two isotopes of oxygen are oxygen-6 and oxygen-8. oxygen-6 oxygen-8 Describe, in terms of particles, how an oxygen-8 atom is different from an oxygen-6 atom (2) (Total 4 marks) Q7. Use the Data Sheet to help you answer this question. When sodium reacts with water it forms sodium ions. The diagrams below represent the electron arrangements of some atoms and ions. Which of the diagrams, A to E, represents the electron arrangement of each of the following? (i) A sodium atom, Na... A sodium ion, Na +... Page 7 (Total 2 marks)

18 Q8. Calcium and magnesium are elements. They are found in the Earth s crust as compounds, often carbonates and sulphates. Magnesium is also found as its chloride. (a) Calcium and magnesium are in the same Group in the Periodic Table. State which Group this is.. () Use the Data Sheet to help you to answer this question. (i) Write the chemical formula of magnesium chloride.... () Name the type of bonding in magnesium chloride.... () (Total 3 marks) Q9. Electrons, neutrons and protons are sub-atomic particles. (a) Complete the six spaces in the following table. Name of sub-atomic particle Relative mass Relative charge (3) An aluminium atom has 3 electrons. How are these arranged in shells around the nucleus? () Chromium atoms have 24 protons and 28 neutrons. (i) How many electrons does each neutral chromium atom have?... () Page 8

19 What is the mass number of chromium?... () (d) What change occurs to an atom which undergoes the process of reduction in a chemical reaction? () (e) The diagram shows part of the ionic lattice of a sodium chloride crystal. Explain why the ions in this lattice stay in place. (3) (Total 0 marks) Page 9

20 Q20. Hydrogen chloride (HCl) can be made by the reaction of hydrogen (H 2) with chlorine (Cl 2). (a) The diagrams represent molecules of hydrogen and chlorine. Draw a similar diagram to represent a molecule of hydrogen chloride (HCl). You need show only the outer energy level (shell) electrons. () The word equation for the reaction of hydrogen with chlorine is shown below. hydrogen + chlorine hydrogen chloride Write a balanced symbol equation for this reaction.. (2) Hydrogen chloride gas reacts with magnesium to form the ionic compound called magnesium chloride. Use the table of ions on the Data Sheet to help you to write the formula of magnesium chloride.. () (d) Why does magnesium chloride have a much higher melting point than hydrogen chloride?.... (2) (Total 6 marks) C2.3 Analysis and Quantitative Chemistry - Foundation Page 20

21 Q. Calcium oxide (quicklime) is made by heating calcium carbonate (limestone). calcium carbonate calcium oxide + carbon dioxide 00 g? 44 g (a) 44 grams of carbon dioxide is produced when 00 grams of calcium carbonate is heated. Calculate the mass of calcium oxide produced when 00 grams of calcium carbonate is heated. mass... g () What mass of carbon dioxide could be made from 00 tonnes of calcium carbonate? mass... tonnes () (Total 2 marks) Q2. Follow the steps to find the percentage of iron in iron oxide. Relative atomic masses: O 6; Fe 56. (i) Step Calculate the relative formula mass of iron oxide, Fe 2O 3... () Step 2 Calculate the total relative mass of just the iron atoms in the formula, Fe 2O 3.. () (iii) Step 3 Calculate the percentage (%) of iron in the iron oxide, Fe 2O 3... Percentage of iron... % () (Total 3 marks) Page 2

22 Q3. (a) A chemist was asked to identify a nitrogen compound. The chemist carried out an experiment to find the relative formula mass (M r) of the compound. The M r of the compound was 44. Relative atomic masses: N = 4, O = 6 Draw a ring around the formula of the compound. NO NO 2 N 2O 4 N 2O () Potassium nitrate is another nitrogen compound. It is used in fertilisers. It has the formula KNO 3. The M r of potassium nitrate is 0. Calculate the percentage of nitrogen by mass in potassium nitrate. Relative atomic mass: N = 4... Percentage of nitrogen =... % (2) (Total 3 marks) Q4. Iron is an essential part of the human diet. Iron(II) sulfate is sometimes added to white bread flour to provide some of the iron in a person s diet. (a) The formula of iron(ii) sulfate is FeSO 4 Calculate the relative formula mass (M r) of FeSO 4 Relative atomic masses: O = 6; S = 32; Fe = The relative formula mass (M r) =... (2) Page 22

23 What is the mass of one mole of iron(ii) sulfate? Remember to give the unit.... () What mass of iron(ii) sulfate would be needed to provide 28 grams of iron? Remember to give the unit.... () (Total 4 marks) Q5. Toothpastes often contain fluoride ions to help protect teeth from attack by bacteria. Some toothpastes contain tin(ii) fluoride. This compound has the formula SnF 2. (a) Calculate the relative formula mass (M r) of SnF 2. Relative atomic masses: F = 9; Sn = 9 Relative formula mass (M r) =... (2) Calculate the percentage by mass of fluorine in SnF 2. Percentage by mass of fluorine =... % Page 23 (2)

24 A tube of toothpaste contains.2 g of SnF 2. Calculate the mass of fluorine in this tube of toothpaste. Mass of fluorine =... g () (d) The diagram represents the electron arrangement of a fluorine atom. Explain how a fluorine atom can change into a fluoride ion, F. (2) Q6. The result of a process used to detect and identify the colours in two foods, A and B, is shown. (i) Describe the differences between the colours used in food A and food B.... (2) Tick ( ) the name of the process used to detect and identify colours in food. Process ( ) chromatography extraction hardening () Page 24

25 Q7. Chromatography was carried out on a sample of soft drinks to check that they contained only colours that were safe. This is the result. Safe colours Colours from the soft drinks What conclusions about the safety of the colours in the soft drinks A, B, C and D can be made from the results shown by chromatography? Q8. (Total 2 marks) (a) Suggest why it is important to be able to identify the colour additives in food. () Page 25

26 A brown colour used in sweets was analysed using chromatography. The results were compared with those from E04 and E33. What do the results tell you about the brown colour and its suitability for use in sweets? (3) Once all the unsuitable colours are removed, the company claims that its sweets are now free from artificial colours. Does this mean that the sweets contain no additives? Explain your answer. (2) (Total 6 marks) Page 26

27 Q9. The diagram shows the main parts of an instrumental method called gas chromatography linked to mass spectroscopy (GC-MS). This method separates a mixture of compounds and then helps to identify each of the compounds in the mixture. (a) In which part of the apparatus: (i) is the mixture separated?... () is the relative molecular mass of each of the compounds in the mixture measured?... () (i) Athletes sometimes take drugs because the drugs improve their performance. One of these drugs is ephedrine. Ephedrine has the formula: C 0H 5NO What relative molecular mass (M r) would be recorded by GC-MS if ephedrine was present in a blood sample taken from an athlete? Show clearly how you work out your answer. Relative atomic masses: H = ; C = 2; N = 4; O = Relative molecular mass =... (2) Page 27

28 Another drug is amphetamine which has the formula: C 9H 3N The relative molecular mass (M r) of amphetamine is 35. Calculate the percentage by mass of nitrogen in amphetamine. Relative atomic mass: N = Percentage of nitrogen =... % (2) Athletes are regularly tested for drugs at international athletics events. An instrumental method such as GC-MS is better than methods such as titration. Suggest two reasons why (2) (d) When a blood sample is taken from an athlete the sample is often split into two portions. Each portion is tested at a different laboratory. Suggest why (Total 0 marks) (2) Page 28

29 C2.Structure and bonding, C2.2 Structure and properties & C2.3 Atomic Structure Markscheme - Foundation M. (a) (i) all three correct 2 marks one correct mark 2 4 A [4] M2. (a) 3 4 numbers must be in the order shown electrons have a very small mass compared to protons electrolysis of molten aluminium oxide [4] M3. (a) 4 9 M4. (a) (i) element [2] compound an / one electron from the sodium atom is lost / transferred to form a sodium ion (i) 8 electrons drawn on outer energy level / shell Page 29

30 because oppositely charged ions attract each other or because chloride ions are negative and sodium ions are positive [6] M5. (i) two or 2 magnesium and chloride (iii) 2 (iv) electrons accept charges (v) any three from M6. (a) (is a) giant structure/lattice structure crystalline / hard accept just 'crystals(s) high melting point / solid high boiling point conductor (of electricity) when dissolved in water or conductor (of electricity) when ions are free to move conductor (of electricity) when molten soluble in water 3 [7] all three lines correct gains 2 marks one or two correct gains mark if there are more than 3 lines then lose mark for each extra line Page 30 2

31 (i) covalent (iii) (iv) (v) four hard three soft carbon accept C [8] M7. (a) CH 4 4 should be below halfway up H / tail of 4 below the dotted line molecule covalent [3] M8. (a) C 3H 8 capital letters for symbols numbers must be halfway or lower down the element symbol allow H 8C 3 do not allow 3:8 or C 3 and H 8 (i) electron covalent low and small both for mark [4] M9. (a) metals copper atoms are arranged in layers copper atoms can slide over each other. the layers of atoms are distorted in bronze [4] Page 3

32 M0. (a) atoms mixture metal structure smart M. (a) (i) small or few atoms thick or size in the range 00 nanometres owtte sensible idea of passing through smaller gaps owtte eg can pass through skin / pores / cells or more easily absorbed any two from: good at absorbing UV light / radiation spread more easily cover better save money / use less transparent less chance of getting skin cancer or stops skin cancer ignore more effective alone 2 toxic to (cells / specific cells) allow harm / damage / kill or cause cancer Page 32

33 M2. (a) mark each, in these positions only 3 4 A [5] M3. (a) Cu Fe Zn one significant use for each metal do not credit vague answers such as in experiments and the like do not credit the same use more than once copper examples: do not credit diet supplement coins or coinage (metal) or make alloys or bronze or brass conducting electricity or (electrical) wiring or motors or cables (domestic) (water) pipes heat exchangers roofing steam pipes Page 33

34 stills or cooking utensils iron or steel answers examples: do not credit diet supplement * access-hole covers (sometimes known as manhole covers) * catalyst (in the production of ammonia) * manufacture of steel(s) or in the basic oxygen process * named vehicle or transport or machinery or railings any other uses for iron and steel can be credited provided that the use is clear so, for example, bridges and railway lines would be creditworthy but do not credit buildings and transport which are too vague any three general properties of do not credit hard or strong or tough or magnetic are not brittle accept can be bent (into shape) or flexible can be hammered (into shape) accept are malleable can be stretched (into shape) accept are ductile (good) conductors of heat accept just (good) conductor once only (good) conductors of electricity high boiling points high density or heavy or dense high melting points ringing sound when struck accept sonorous solids (at room temperature) accept shiny (when polished) or silvery 4 (d) any one of do not credit electron references * (good) conductor (of electricity) when molten or liquid Page 34

35 accept dissolves in water or crystalline * (good) conductor (of electricity) when in aqueous solution accept (good) conductor (of electricity) when dissolved in water * high melting point or high boiling point do not credit just solid (e) (i) electron from A to B both parts required different numbers of protons accept different atomic numbers do not credit references to neutrons [3] M4. (a) covalent (i) liquid fluorine accept F / F 2 do not accept fluoride M5. (a) (i) gives out a large amount of energy only water produced / product is non polluting (owtte) allow it does not harm the environment does not explode / burst into flames owtte ignore will not react (iii) hydrogen absorbed and released much faster allow more efficient allow can store a larger amount Page 35

36 (i) B (iii) a lithium atom loses an electron C reversible (d) (i) much smaller surface area [0] M6. (a) (i) nucleus it has 2 more neutrons or converse or O-6 has 8 neutrons ( mark) O-8 has 0 neutrons ( mark) 2 [4] M7. (i) B or 2, 8, for one mark A or 2, 8 for one mark [2] Page 36

37 M8. (a) Group 2 / Alkaline Earth Metals for mark (i) MgCl 2/Mg 2+ (Cl ) 2 (or equation with correct answer) for mark ionic / electrovalent for mark [3] M9. (a) proton + () both required neutron both required electron () both required accept words or diagram to this effect (i) (d) any one of gains one or more electrons accept gains an electron becomes an anion do not credit becomes an ion becomes a negative ion (e) sodium ions have a (single) positive charge and chloride ions have a (single) negative charge Page 37

38 do not credit chlorine ions but allow this error to be carried forward ions with opposite charge are attracted (to each other) or the positive ions and the negative ions are attracted (to each other) or the sodium ions and the chloride ions are attracted (to each other) (positive and negative) ions are arranged alternatively (in each direction or dimension) or ions with the same charge are repelled (by each other) no mark for just ionic bonds [0] M20. (a) bonding pair in the overlap and 6 other electrons arranged around the chlorine must have either circles or symbols need not be pairs but must not be in the overlap region accept without H and Cl if clear accept all x s or all o s H 2 + Cl 2 2HCl accept multiples or fractions accept correct formulae but not balanced for mark correctly balanced equation containing correct lower / upper case symbols gets mark 2 Page 38

39 MgCl 2 accept Mg 2+ (Cl ) 2 (d) because magnesium chloride is made of ions or is ionic accept there are strong forces of attraction between the ions / particles in MgCl 2 or strong electrostatic attractions accept more energy to separate particles in MgCl 2 do not accept MgCl 2 molecules do not accept reference to breaking bonds hydrogen chloride is made of molecules or is covalent accept there are only weak forces of attraction (between the particles / molecules) in HCl do not accept weak covalent bonds do not accept reference to breaking bonds do not accept MgCl 2 is a solid and HCl is a gas [6] Page 39

40 C2.3 Analysis and Quantitative Chemistry Markscheme - Foundation M. (a) 56g for mark 44 tonnes for mark [2] M2. (i) 60 2 (iii) 70 M3. (a) N 2O ignore units ignore units do not carry forward errors [3] 3.8 to 4 gains full marks without working if answer incorrect 3 gains mark or 4/0 00 gains mark M4. (a) 52 correct answer with or without working = 2 marks (4 6) gains mark ignore any units 2 2 [3] 52g(rams) ecf from the answer to (a) and g must have unit g / gram / gramme / grams etc accept g / mol or g per mole or g mole or g/mol or g per mol or g mol do not accept g m do not accept G 76(g) ecf from their answer to (a) or divided by 2 ignore units [4] Page 40

41 M5. (a) correct answer with or without working ( ) for mark only allow (9 + 9 =) 38 for mark only ignore units accept answers in the range 24 to ignore incorrect rounding after correct answer 25 only without working gains mark or 38/57 00 gains mark or (9/57 00 =) 2 to 2. gains mark allow error carried forward from part(a) 38/(a) 00 gains 2 marks if calculated correctly (9/38 00 =) 3.8 gains mark accept answers in the range 0.28 to 0.3 allow error carried forward from part /00.2 correctly calculated ignore units 2 2 (d) an electron allow electrons allow electron shared / lost for mark apply list principle for additional particles is gained owtte must be linked to electron accept can hold / take in if in correct context eg it can hold another electron (in its outer shell) = 2 marks it can take an electron (from another atom) = 2 marks M6. (i) any two from: A has four colours(*) B has three colours(*) (*) if first two bullets not stated accept A has more colours (than B) or B has less colours (than A) for mark only A / B have two colours the same B has one different colour 2 chromatography [3] Page 4

42 M7. drinks / colours B and C are safe drinks / colours A and D are not safe accept a pair of one safe colour and one not safe colour identified for mark accept A, B, C and D all contain one safe colour for mark ignore references to shading M8. (a) check if safe to eat / healthy or [2] permitted accept references to allergies / medical problems any three from: accept dye for colour made up of two colours / dots contains an unknown colour / dot contains a harmful colour contains E04 / quinoline yellow or does not contain E33 / brilliant blue further analysis needed 3 ignore No or Yes but No must be implied there could be other additives (in the sweets) accept any other type of additives but not colourings could still contain / use / add natural colours accept non-artificial for natural or named natural colours [6] Page 42

43 M9. (a) (i) column mass spectrometer (i) 65 if answer is not correct then evidence of correct working gains one mark. e.g. (0 2) % accept 0 / 0.4 / if answer is not correct then evidence of correct working gains one mark. e.g. minimum evidence would be 4/35 2 any two from: faster more accurate detects smaller amounts 2 (d) to avoid bias accept to check / compare the result to improve reliability [0] Page 43