n5 chemistry all 2014 - glow blogs · attempt all questions in this section. write your answers...

Necessary data will be found in the Chemistry Data Booklet for National 5.

Instructions for the completion of Section 1 are given on Page two of your question and answer booklet X713/75/01.

Record your answers on the answer grid on Page three of your question and answer booklet

Before leaving the examination room you must give your question and answer booklet to the Invigilator; if you do not, you may lose all the marks for this paper.

N5X713/75/02 Chemistry

Section 1—Questions

MONDAY, 12 MAY

9:00 AM—11:00 AM

*X7137502*

©

NationalQuali cations2014

LI

Page two

SECTION 1

1. In a reaction, 60 cm3 of hydrogen gas was collected in 20 s.

What is the average rate of reaction, in cm3 s–1, over this time?

A

B

C

D

2. Molecules in which four different atoms are attached to a carbon atom are said to be chiral.

Which of the following molecules is chiral?

A

B

C

D

Br

ClH H

C

Br

HH H

C

I

HCl H

C

I

FH Br

C

6020

2060

160

120

Page three

3. What is the charge on the zinc ion in the compound zinc phosphate Zn3(PO4)2?

A 2+

B 3+

C 2−

D 3−

4. Fe2O3 + x CO y Fe + 3CO2

This equation will be balanced when

A x = 1 and y = 2

B x = 2 and y = 2

C x = 3 and y = 2

D x = 2 and y = 3.

5. An acidic solution contains

A only hydrogen ions

B only hydroxide ions

C more hydrogen ions than hydroxide ions

D more hydroxide ions than hydrogen ions.

6. Which of the following oxides, when shaken with water, would give an alkaline solution?

A Calcium oxide

B Nickel oxide

C Nitrogen dioxide

D Sulfur dioxide

7. Which of the following compounds is not a salt?

A Calcium nitrate

B Sodium chloride

C Potassium sulfate

D Magnesium hydroxide

[Turn over

Page four

8. H+(aq) + NO3—(aq) + K+(aq) + OH—(aq) K+(aq) + NO3

—(aq) + H2O(ℓ)

The spectator ions present in the reaction above are

A K+(aq) and NO3—(aq)

B K+(aq) and H+(aq)

C OH—(aq) and NO3—(aq)

D H+(aq) and OH—(aq).

9. The molecular formula for cyclohexane is

A C6H6

B C6H10

C C6H12

D C6H14.

10.

The systematic name for the structure shown is

A 1,1-dimethylpropane

B 2-methylbutane

C 3-methylbutane

D 2-methylpentane.

CH

H H

CH CC

H HH

H

H

HC

H

H

Page five

11. Petrol is a mixture of hydrocarbons.

The tendency of a hydrocarbon to ignite spontaneously is measured by its octane number.

Hydrocarbon Octane number

1 3-methylpentane 74·5

2 butane 93·6

3 pentane 61·7

4 2-methylpentane 73·4

5 hexane 24·8

6 methylcyclopentane 91·3

A student made the hypothesis that as the chain length of a hydrocarbon increases, the octane number decreases.

Which set of three hydrocarbons should have their octane numbers compared in order to test this hypothesis?

A 1, 4, 6

B 1, 2, 4

C 2, 3, 5

D 3, 4, 5

12. Propene reacts with hydrogen bromide to form two products.

H HH

CH CC

H

HHBr

H HH

HBr

CH CC

H

H

H HH

BrH

CH CC

H

H

Which of the following alkenes does not form two products on reaction with hydrogen bromide?

A But-1-ene

B But-2-ene

C Pent-1-ene

D Pent-2-ene

[Turn over

Page six

13. Which of the following alcohols has the highest boiling point?

You may wish to use your data booklet to help you.

A Propan-1-ol

B Propan-2-ol

C Butan-1-ol

D Butan-2-ol

14. A reaction is endothermic if

A energy is required to start the reaction

B heat is released during the reaction

C the temperature drops during the reaction

D the temperature rises during the reaction.

15. Which of the following metals will not react with a dilute solution of hydrochloric acid?

A Copper

B Iron

C Magnesium

D Zinc

16. Which metal can be extracted from its oxide by heat alone?

A Tin

B Zinc

C Lead

D Silver

Page seven

17. The ion-electron equations for the oxidation and reduction steps in the reaction between sulfite ions and iron(III) ions are given below.

oxidation H2O(ℓ) + SO32—(aq) SO4

2—(aq) + 2H+(aq) + 2e—

reduction Fe3+(aq) + e— Fe2+(aq)

The redox equation for the overall reaction is

A H2O(ℓ) + SO32—(aq) + Fe3+(aq) SO4

2—(aq) + 2H+(aq) + Fe2+(aq) + e—

B H2O(ℓ) + SO32—(aq) + 2Fe3+(aq) SO4

2—(aq) + 2H+(aq) + 2Fe2+(aq)

C SO42—(aq) + 2H+(aq) + Fe2+(aq) + e— H2O(ℓ) + SO3

2—(aq) + Fe3+(aq)

D SO42—(aq) + 2H+(aq) + 2Fe2+(aq) H2O(ℓ) + SO3

2—(aq) + 2Fe3+(aq).

18. The apparatus below was set up.

metal X metal Y

sodiumchloridesolution

Which of the following pairs of metals would give the highest reading on the voltmeter?

Metal X Metal Y

A Iron Zinc

B Magnesium Silver

C Zinc Copper

D Zinc Silver

[Turn over

V

Page eight

19. A section of a condensation polymer is shown below.

C

O

OC

O

CO

O

C

O

C6H

4C6H

4(CH2)2

H CO

O

C

O

OC6H

4

One of the monomers is

H

The structural formula for the other monomer is

A

B

C

D

20. Ba2+(aq) + 2NO3—(aq) + 2Na+(aq) + SO4

2—(aq) Ba2+SO42—(s) + 2Na+(aq) + 2NO3

—(aq)

The type of reaction represented by the equation above is

A addition

B displacement

C neutralisation

D precipitation.

[END OF SECTION 1. NOW ATTEMPT THE QUESTIONS IN SECTION 2 OF YOUR QUESTION AND ANSWER BOOKLET]

H OC

O

CO

O

H(CH2)2

H CO OC H(CH2)2

O O

H CO HO(CH2)2

O

H O O H(CH2)2

FOR OFFICIAL USE

N5Chemistry

Section 1—Answer Grid And Section 2

Fill in these boxes and read what is printed below.

Full name of centre Town

Forename(s) Surname Number of seat

Day Month Year Scottish candidate number

*X7137501*

*X713750101*

©

D D M M Y Y

Mark

NationalQuali cations2014

Date of birth

MONDAY, 12 MAY

9:00 AM—11:00 AM

Necessary Data will be found in the Chemistry Data Booklet for National 5.

Total marks—80

SECTION 1—20 marks

Attempt ALL questions in this section.

Instructions for the completion of Section 1 are given on Page two.


Attempt ALL questions in this section.

Write your answers clearly in the spaces provided in this booklet. Additional space for answers and rough work is provided at the end of this booklet. If you use this space you must clearly identify the question number you are attempting. Any rough work must be written in this booklet. You should score through your rough work when you have written your final copy.

Use blue or black ink.

Before leaving the examination room you must give this booklet to the Invigilator; if you do not, you may lose all the marks for this paper.

X713/75/01

LI

*X713750102*

The questions for Section 1 are contained in the question paper X713/75/02.Read these and record your answers on the answer grid on Page three opposite.Do NOT use gel pens.

1. The answer to each question is either A, B, C or D. Decide what your answer is, then fill in the appropriate bubble (see sample question below).

2. There is only one correct answer to each question.

3. Any rough work must be written in the additional space for answers and rough work at the end of this booklet.

Sample Question

To show that the ink in a ball-pen consists of a mixture of dyes, the method of separation would be

A fractional distillation

B chromatography

C fractional crystallisation

D filtration.

The correct answer is B—chromatography. The answer B bubble has been clearly filled in (see below).

A B C D

Changing an answer

If you decide to change your answer, cancel your first answer by putting a cross through it (see below) and fill in the answer you want. The answer below has been changed to D.

A B C D

If you then decide to change back to an answer you have already scored out, put a tick (✓) to the right of the answer you want, as shown below:

A B C D

or

A B C D


Page two

*X713750103*

SECTION 1 — Answer Grid

[Turn over

A B C D

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

* 20 1*

Page three

*X71375010 *Page four

[BLANK PAGE]

DO NOT WRITE ON THIS PAGE

*X713750105*Page five

[Turn over for Question 1 on Page six


*X71375010 *

MARKS DO NOT WRITE IN

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Page six

SECTION 2—60 marksAttempt ALL questions

1. In 1911, Ernest Rutherford carried out an experiment to confirm the structure of the atom. In this experiment, he fired positive particles at a very thin layer of gold foil. Most of the particles passed straight through but a small number of the positively charged particles were deflected.

path of positive particles goldatoms

(a) What caused some of the positive particles to be deflected in this experiment?

(b) Gold is the heaviest element to have only one naturally occurring isotope.

The isotope has a mass number of 197.

(i) Complete the table to show the number of each type of particle in this gold atom.

You may wish to use the data booklet to help you.

Particle Number

Proton

Electron

Neutron

(ii) Most elements have more than one isotope.

State what is meant by the term isotope.

Total marks

1

1

1

3

*X713750107*


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Page seven

2. (a) The properties of a substance depend on its type of bonding and structure. There are four types of bonding and structure.

Discretecovalent

molecular

Covalentnetwork

Ioniclattice

Metalliclattice

Complete the table to match up each type of bonding and structure with its properties.

Type of bonding and structure Properties

do not conduct electricity and have high melting points

have high melting points and conduct electricity when liquid but not when solidconduct electricity when solid and have a wide range of melting points

do not conduct electricity and have low melting points

(b) Graphene is a substance made of a single layer of carbon atoms.

Graphene can conduct electricity.

Suggest what this indicates about some of the electrons in graphene.

Total marks

2

1

3

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*X71375010 *


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Page eight

3. Read the passage below and answer the questions that follow.

Potassium - The Super Element

Potassium is an essential element for almost all living things. The human body requires a regular intake of potassium because humans have no mechanism for storing it. Foods rich in potassium include raisins and almonds. Raisins contain 0·86 g of potassium in every 100 g.

Naturally occurring salts of potassium such as saltpetre (potassium nitrate) and potash (potassium carbonate) have been known for centuries. Potassium salts are used as fertilisers.

Potassium was first isolated by Humphry Davy in 1807. Davy observed that when potassium was added to water it formed globules which skimmed about on the surface, burning with a coloured flame and forming an alkaline solution.

(a) State why the human body requires a regular intake of potassium.

(b) Calculate the number of moles of potassium in 100 g of raisins.

Show your working clearly.

(c) State the colour of the flame which would be seen when potassium burns.


(d) Write the ionic formula for saltpetre.

Total marks

1

2

1

1

5

*X71375010 *


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Page nine

4. Poly(vinylcarbazole) is a plastic which conducts electricity when exposed to light.

The structure of the monomer used to make poly(vinylcarbazole) is

H H

C C

NC12H8 H

(a) Draw a section of the polymer showing three monomer units joined together.

(b) Name the type of polymerisation taking place when these monomers join together.

Total marks

[Turn over

1

1

2

*X713750110*


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Page ten

5. Different types of radiation have different penetrating properties.

An investigation was carried out using three radioactive sources.

Radioactivesource

paper aluminium lead

1

2

3

(a) Name the type of radiation emitted by source 2.

(b) The half-life of source 3 is 8 days.

Calculate the fraction of source 3 that would remain after 16 days.


(c) Radioisotopes can be made by scientists.

The nuclear equation shows how a radioisotope of element X can be made from aluminium.

2713

10Al + n X + He4

2

Name element X.

Total marks

1

2

1

4

*X713750111*


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Page eleven

6. A student reacted acidified potassium permanganate solution with oxalic acid, C2H2O4.

2MnO4–(aq) + 5C2H2O4(aq) + 6H+(aq) 2Mn2+(aq) + 10CO2(g) + 8H2O(ℓ)

Using your knowledge of chemistry, comment on how the student could have determined the rate of the reaction.

[Turn over

3

*X713750112*


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Page twelve

7. The manufacture of potassium nitrate, for use in fertilisers, can be split into three stages.

(a) (i) In stage 1, ammonia is produced.

Name the industrial process used to manufacture ammonia.

(ii) Draw a diagram to show how all the outer electrons are arranged in a molecule of ammonia, NH3.

(b) In stage 2, ammonia is converted into nitric acid, HNO3, as shown in the flow diagram.

ammonia air

reactor

nitrogenmonoxide

oxygen

nitrogendioxide

nitrogenmonoxide absorber

nitric acid

X

1

1

*X713750113*


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Page thirteen

7. (b) (continued)

(i) Name substance X.

(ii) On the flow diagram, draw an arrow to show how the process can be made more economical.

(c) In stage 3, nitric acid is converted to potassium nitrate.

The equation for the reaction taking place is

HNO3(aq) + KOH(aq) KNO3(aq) + H2O(ℓ)

(i) Name the type of chemical reaction taking place in stage 3.

(ii) State how a sample of solid potassium nitrate could be obtained from the potassium nitrate solution.

Total marks

[Turn over

1

1

1

1

6

*X71375011 *


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Page fourteen

8. Pheromones are chemicals, produced by living things, that trigger a response in members of the same species.

When a bee stings an animal the bee also releases a pheromone containing the ester below.

CC

H

H H

HO

HC O

C

HH

H C

CH

H

H

H

H

C H

(a) State another use for esters.

(b) A student made the ester above using ethanoic acid and the following alcohol.

CH

H

H H

C

CH

H

H

H

H

C C

H

H

O H

(i) Name the functional group present in this alcohol.

(ii) Draw a structural formula for an isomer of this alcohol.

1

1

1

*X713750115*


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Page fifteen

8. (b) (continued)

(iii) Ethanoic acid is the second member of a family of compounds which contain the carboxyl functional group.

The full structural formulae for the first three members of this family are shown.

C

H

H

H HC

O

OC

H

H

HH

C

O

O HC

H

H

C

O

O H

methanoicacid

ethanoicacid

propanoicacid

Suggest a general formula for this family of compounds.

(c) The table gives information on some other esters.

Alcohol Carboxylic acid Ester

methanol ethanoic acid methyl ethanoate

propanol methanoic acid propyl methanoate

butanol ethanoic acid butyl ethanoate

pentanol butanoic acid pentyl butanoate

X Y ethyl propanoate

Name X and Y.

Total marks

1

2

6

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*X71375011 *


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Page sixteen

9. Liquefied petroleum gas (LPG), which can be used as a fuel for heating, is a mixture of propane and butane.

(a) Propane and butane are members of the homologous series of alkanes.

Tick (✓) the two boxes that correctly describe members of the same homologous series.

Tick (✓)

They have similar chemical properties.

They have the same molecular formula.

They have the same general formula.

They have the same physical properties.

They have the same formula mass.

(b) The table gives some information about propane and butane.

Alkane Boiling Point (°C)

propane − 2

butane −

Explain why butane has a higher boiling point than propane.

1

2

*X713750117*


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Page seventeen

9. (continued)

(c) 25 kg of water at 10 °C is heated by burning some LPG.

Calculate the energy, in kJ, required to increase the temperature of the water to 30 °C.



(d) LPG is odourless. In order to detect gas leaks, ethyl mercaptan, C2H6S, a smelly gas, is added in small quantities to the LPG mixture.

Suggest one disadvantage of adding sulfur compounds, such as ethyl mercaptan, to fuels such as LPG.

Total marks

3

1

7

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*X71375011 *


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Page eighteen

10. The lowest temperature at which a hydrocarbon ignites is called its flash point.

Hydrocarbon Flash point (°C)

hexane −23

heptane −

octane 13

nonane 31

(a) (i) Using the information in the table, make a general statement linking the flash point to the number of carbon atoms.

(ii) Predict the flash point, in °C, of decane, C10H22.

1

1

*X71375011 *


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Page nineteen

10. (continued)

(b) Nonane burns to produce carbon dioxide and water.

C9H20 + 14O2 9CO2 + 10H2O

Calculate the mass, in grams, of carbon dioxide produced when 32 g of nonane is burned.


Total marks

[Turn over

3

5

*X713750120*


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Page twenty

11. Chlorine can be produced commercially from concentrated sodium chloride solution in a membrane cell. Only sodium ions can pass through the membrane. These ions move in the direction shown in the diagram.

Cl2(g) membrane H2(g)

dilutesodium chloridesolution

concentratedsodium chloridesolution

Na+(aq)ions

water

solution X

+veelectrode

-veelectrode

(a) Write the ion-electron equation for the change taking place at the positive electrode.


(b) (i) Name solution X.

(ii) The hydrogen gas produced, at the negative electrode, can be used as a fuel.

Suggest an advantage of using hydrogen as a fuel.

1

1

1

*X713750121*


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Page twenty-one

11. (continued)

(c) The chlorine gas produced can be used to make phosgene, COCl2. Phosgene is used in the manufacture of drugs and plastics.

Draw a possible structure for phosgene.

Total marks

[Turn over

1

4

*X713750122*


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Page twenty-two

12. Ores are naturally occurring compounds from which metals can be extracted.

(a) When a metal is extracted from its ore, metal ions are changed to metal atoms.

Name this type of chemical reaction.

(b) Iron can be extracted from its ore haematite, Fe2O3, in a blast furnace.

Calculate the percentage by mass of iron in haematite.


(c) Magnesium cannot be extracted from its ore in a blast furnace.

Suggest a method that would be suitable for the extraction of magnesium from its ore.

Total marks

1

3

1

5

*X713750123*


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Page twenty-three

13. Sodium carbonate solution can be added to the water in swimming pools to neutralise the acidic effects of chlorine.

A student carried out a titration experiment to determine the concentration of a sodium carbonate solution.

hydrochloricacid0·1 mol l-1

10 cm3

sodium carbonatesolution and indicator

Rough titre

1st titre

2nd titre

Initial burette reading (cm3) 0·0 0·0 0·0

Final burette reading (cm3) 16·5 15·9 16·1

Volume used (cm3) 16·5 15·9 16·1

(a) Using the results in the table, calculate the average volume, in cm3, of hydrochloric acid required to neutralise the sodium carbonate solution.

(b) The equation for the reaction is

2HCl + Na2CO3 2NaCl + CO2 + H2O

Using your answer from part (a) calculate the concentration, in mol l-1, of the sodium carbonate solution.


Total marks

1

3

4

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Page twenty-four

14. Chemistry in the cinema.

In the film Dante’s Peak, a family trapped by red hot lava escape by crossing a large lake in a boat made from aluminium. The volcano releases heat and the gases hydrogen chloride, sulfur dioxide and sulfur trioxide into the water in the lake. While crossing the lake, holes begin to appear in the bottom of the boat. Just after the family leave the boat, on the other side of the lake, the boat sinks.

Using your knowledge of chemistry, comment on whether or not the events described in the film could take place.

[END OF QUESTION PAPER]

3

*X713750125*


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Page twenty-five

ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK

*X71375012 *


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ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK

*X713750127*Page twenty-seven

[BLANK PAGE]


*X71375012 *Page twenty-eight

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National Qualifications 2014

2014 Chemistry

National 5

Finalised Marking Instructions � Scottish Qualifications Authority 2014 The information in this publication may be reproduced to support SQA qualifications only on a non-commercial basis. If it is to be used for any other purposes written permission must be obtained from SQA’s NQ Assessment team. Where the publication includes materials from sources other than SQA (secondary copyright), this material should only be reproduced for the purposes of examination or assessment. If it needs to be reproduced for any other purpose it is the centre’s responsibility to obtain the necessary copyright clearance. SQA’s NQ Assessment team may be able to direct you to the secondary sources. These Marking Instructions have been prepared by Examination Teams for use by SQA Appointed Markers when marking External Course Assessments. This publication must not be reproduced for commercial or trade purposes.

©

Page two

General Marking Principles for National 5 Chemistry This information is provided to help you understand the general principles you must apply when marking candidate responses to questions in this Paper. These principles must be read in conjunction with the detailed marking instructions, which identify the key features required in candidate responses. (a) Marks for each candidate response must always be assigned in line with these General

Marking Principles and the Detailed Marking Instructions for this assessment. (b) Marking should always be positive. This means that, for each candidate response, marks

are accumulated for the demonstration of relevant skills, knowledge and understanding: they are not deducted from a maximum on the basis of errors or omissions. A guiding principle in marking is to give credit for correct chemistry rather than to look for reasons not to award marks. Example 1: The structure of a hydrocarbon found in petrol is shown below. Name the hydrocarbon. Although the punctuation is not correct, ‘3, methyl-hexane’ should gain the mark. Example 2: A student measured the pH of four carboxylic acids to find out how their strength is related to the number of chlorine atoms in the molecule. The results are shown in the table.

Structural formula pH

CH3COOH 1·65 CH2ClCOOH 1·27 CHCl2COOH 0·90 CCl3COOH 0·51

State how the strength of the acids is related to the number of chlorine atoms in the molecule. Although not completely correct, an answer such as ‘the more Cl2, the stronger the acid’ should gain the mark.

(c) There are no half marks awarded. (d) Candidates must respond to the “command” word as appropriate and may be required

to write extended answers in order to communicate fully their knowledge and understanding.

Page three

(e) Marks should be awarded for answers that have incorrect spelling or loose language as

long as the meaning of the word(s) is conveyed. Example: Answers like ‘distilling’ (for ‘distillation’) and ‘it gets hotter’ (for ‘the temperature rises’) should be accepted. However the example below would not be given any credit, as an incorrect chemical term, which the candidate should know, has been given. Example: If the correct answer is “ethene”, and the candidate’s answer is “ethane”, this should not be accepted.

(f) A correct answer followed by a wrong answer should be treated as a cancelling error and no marks should be awarded. Example: State what colour is seen when blue Fehling’s solution is warmed with an aldehyde. The answer ‘red, green’ gains no marks.

(g) If a correct answer is followed by additional information which does not conflict, the additional information should be ignored, whether correct or not. Example: State why the tube cannot be made of copper. If the correct answer is related to a low melting point, ‘Copper has a low melting point and is coloured grey’ would not be treated as having a cancelling error.

(h) Unless a numerical question specifically requires evidence of working to be shown, full marks should be awarded for a correct final answer (including units if required) on its own. The partial marks shown in the marking scheme are for use when working is given but the final answer is incorrect. An exception is when candidates are asked to ‘Find, by calculation’, when full marks cannot be awarded for the correct answer without working.

(i) Where the marking instructions specifically allocate a mark for units in a calculation, this mark should not be awarded if the units are incorrect or missing. Missing or incorrect units at intermediate stages in a calculation should be ignored.

(j) As a general rule, where a wrong numerical answer (already penalised) is carried

forward to another step, credit will be given provided the result is used correctly. The exception to this rule is where the marking instructions for a numerical question assign separate “concept marks” and an “arithmetic mark”. In such situations, the marking instructions will give clear guidance on the assignment of partial marks.

(k) Ignore the omission of one H atom from a full structural formula provided the bond is shown.

(l) A symbol or correct formula should be accepted in place of a name unless stated otherwise in the marking instructions.

Page four

(m) When formulae of ionic compounds are given as answers it will only be necessary to

show ion charges if these have been specifically asked for. However, if ion charges are shown, they must be correct. If incorrect charges are shown, no marks should be awarded.

(n) If an answer comes directly from the text of the question, no marks should be awarded.

Example: A student found that 0·05 mol of propane, C3H8 burned to give 82· 4 kJ of energy.

C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(ℓ)

Name the type of enthalpy change which the student measured.

No marks should be awarded for 'burning' since the word ‘'burned’ appears in the text. (o) Unless the question is clearly about a non-chemistry issue, eg costs in industrial

chemical process, a non-chemical answer gains no marks.

Example: Suggest why the (catalytic) converter has a honeycomb structure. A response such as ‘to make it work’ may be correct but it is not a chemical answer and the mark should not be awarded.

Page five

Marking Instructions for each question

Section 1

Question Answer Max Mark

1. A 1

2. D 1

3. A 1

4. C 1

5. C 1

6. A 1

7. D 1

8. A 1

9. C 1

10. B 1

11. C 1

12. B 1

13. C 1

14. C 1

15. A 1

16. D 1

17. B 1

18. B 1

19. B 1

20. D 1

Page six

Section 2

Question Answer Max Mark Additional Guidance 1. (a) Repulsion/repelled by

nucleus/positive nucleus /protons/positive protons/positive particles in nucleus or in atom or in gold/ like charges in nucleus, atom or gold

1 Zero marks for just mentioning positive particles/protons etc in nucleus without mentioning them repelling Zero marks for positive particles or like charges without mentioning it is those in nucleus or atom or gold Zero marks for positive charge of the gold atoms

(b) (i) Protons – 79 Electrons – 79 Neutrons – 118 All for 1 mark

1

(ii) Same atomic number / protons AND different mass number / mass / number of neutrons Atoms of the same element with different mass number / mass /number of neutrons Candidate must specify either same atomic number or number of protons/positive charges or atoms of the same element AND different mass number/mass/number of neutrons

1 If electrons mentioned this does not negate a correct answer Do not accept Particles, molecules or same atoms with … Same element with different mass number

Question Answer Max Mark Additional Guidance 2. (a) Covalent network

Ionic lattice Metallic lattice (Discrete) covalent molecular

2

All 4 correct - 2 marks 2 or 3 correct - 1 mark 1 or 0 correct - 0 marks

(b) Delocalised /able or free to move or correct description

1

Mention of ions negates correct answer

Page seven

Question Answer Max Mark Additional Guidance 3. (a) Potassium is an essential

element or humans / human body cannot store it / have no mechanism for storing it

1

(b) 0�022 or 0·02 (moles) with no working (2) 0·86 / 39 = (1) 0·022 or 0·02 (moles) (1)

2

Any incorrect answer with no working award zero marks Allow follow through if incorrect value extracted from text and correctly divided by 39. 39/0·86 = 45·34 1 mark 0·86/100 = 0·0086 1 mark 100/39 = 2·56 1 mark Any other response zero marks If incorrect unit used maximum of 1 mark awarded Accept mol(s) Do not accept ml, g

(c) Lilac/purple 1

(d) K+ NO3-

both charges must be shown

1

Also accept use of brackets which do not negate the correct ionic formula e.g.

(K+) (NO3-) (K)+ (NO3)

-

K+ (NO3-) (K+) NO3

-

Do not accept (K)+ (NO)3-

K+ No3-

If ionic formula for potash (K+)2

CO32- is given this negates

correct answer unless correct answer is identified by candidate as being saltpetre or potassium nitrate

Page eight

Question Answer Max Mark Additional Guidance 4. (a) 1 Award mark if one end bond is

missing NC12H8 H NC12H8 H NC12H8 H C C C C C C H H H H H H

Award mark if one end bond is shown with other end having a H in place of second end bond

Allow dot or ~ to represent end bond

With or without brackets. The bond to NC12H8 does not need to be drawn to the nitrogen but must be drawn to the group.

Zero marks if both end bonds are missing / both ends have H / less than or more than three monomers shown / bond between two carbon missing

(b) Addition or additional 1

Do not award mark for “adding” Mention of condensation negates correct answer

Question Answer Max Mark Additional Guidance 5. (a) alpha or 1

2+ on their own

not accepted but do not negate Any mention of beta or gamma negates correct answer

(b) ¼ / 0·25 / 25% with no working (2) Two half-lives (1) ¼ or 0·25 or 25% (1)

2

If number of half lives is incorrect allow follow through to second step Incorrect answer with no working zero marks

(c) Sodium / Na

1

If mass/atomic number given they must be correct

chromium zero marks

zero marks

Page nine

Question Answer Max Mark Additional Guidance 6. This is an open ended question

1 mark: The student has demonstrated a limited understanding of the chemistry involved. The candidate has made some statement(s) which is/are relevant to the situation, showing that at least a little of the chemistry within the problem is understood. 2 marks: The student has demonstrated a reasonable understanding of the chemistry involved. The student makes some statement(s) which is/are relevant to the situation, showing that the problem is understood. 3 marks: The maximum available mark would be awarded to a student who has demonstrated a good understanding of the chemistry involved. The student shows a good comprehension of the chemistry of the situation and has provided a logically correct answer to the question posed. This type of response might include a statement of the principles involved, a relationship or an equation, and the application of these to respond to the problem. This does not mean the answer has to be what might be termed an “excellent” answer or a “complete” one.

3

Page ten

Question Answer Max Mark Additional Guidance 7. (a) (i) Haber

1

(ii) Diagram showing three hydrogen atoms and one nitrogen atom with three pairs of bonding electrons and two non-bonding electrons in nitrogen eg

H N H H

1

Accept cross /dot /petal /circles The non-bonding electrons in nitrogen must be shown but do not need to be together / shown as a pair Electrons can be on the line or in the overlapping area. Either the nitrogen or all three hydrogen symbols must be shown If inner electrons on nitrogen are shown they must be correct ie 2 electrons

(b) (i) Water / H2O / Hydrogen oxide 1

(ii) Arrow from nitrogen monoxide from absorber to nitrogen monoxide below reactor (anywhere below the reactor and above nitrogen dioxide)

1

Direction of arrow must be correct

(c) (i) Neutralisation 1

H N

H

H

Page eleven

(ii) Evaporation or boil it / boil off the water or distillation or correct description

1

Filtration on its own is not acceptable It negates the correct answer if stated evaporation OR filtration/ evaporation and filtration/ filtration then leave to dry ( unless stated filtrate left to dry) It does not negate if stated filtration followed by evaporation Filtration then evaporation/ filtration followed by evaporation accepted. Filtration and evaporation zero marks.

Page twelve

Question Answer Max Mark Additional Guidance 8. (a) Perfumes, solvents, flavourings,

fragrances, preservatives 1

If other answers are given the marker must be confident that esters are used for this purpose. Markers should check accuracy Also accept uses of polyesters But no marks awarded for esters are used to make polyesters

(b) (i) Hydroxyl 1 Zero marks for hydroxide. If hydroxide is given along with hydroxyl – zero marks. Zero marks for OH or OH circled in molecule however these do not negate hydroxyl

(b) (ii) Any correct full or shortened structural formula for an isomer

1

Incorrect name with a correctly drawn structural formula does not negate correct answer If shortened structure is used for a branch in a structure the bond must be to the carbon of the branch If isomer is another alcohol the carbon must be bonded to the oxygen of the hydroxyl group

(b) (iii) CnH2nO2 CnH2n+1COOH

1

Accept n or x Not acceptable CnH2n + O2

CnH2n 2O The symbols can be in any order The subscripts must be a smaller font size than symbol

CnH2nO2 - not acceptable

Page thirteen

Question Answer Max Mark Additional Guidance (c) ethanol (1)

propanoic acid (1) Spelling of both must be correct

2

If they specify which is X and which is Y they must be correct eg X is ethanol Y= propanoic acid X = propanoic acid Y= ethanol is awarded zero marks If the name of two acids or two alcohols are given zero marks awarded unless specified as X and Y eg X is ethanol award 1 Y is propanol Ethanol and propanol award 0

Page fourteen

Question Answer Max Mark Additional Guidance 9. (a) They have similar chemical

properties and They have the same general formula. Both required for 1 mark

1

Correct answers can be ticked, circled or highlighted in some other way. If more than two boxes ticked zero marks awarded.

(b) Butane, or it, has stronger / more / bigger forces of attraction (1) between molecules or mention of intermolecular attractions (1) If neither of these two points are given a maximum of one mark can be awarded for Butane is bigger / has more carbon or hydrogens / longer carbon chain

2

The term bond is only acceptable if it is specifically identified as between the molecules or used with the term intermolecular. Mention of breaking bonds/bonds within molecule or chain/ breaking carbon to carbon or carbon to hydrogen bonds or more bonds cannot gain the second mark but does not negate the first mark 2 marks can be awarded if candidate explains why propane has a lower boiling point but they must state propane in answer. 1 mark - propane is smaller / has less carbon or hydrogens / smaller carbon chain. Propane must be stated to gain the mark

Page fifteen

(c) 2090 with no working = (3) EH =cmΔT = 4�18x 25 x 20 =2090 (3) using concept cmΔT with c = 4·18 (1) using correct data ie 25 and 20 (1) final answer 2090 (1) If awarding partial marks, the mark for the final answer can only be awarded if the concept mark has been awarded.

3

Ignore negative sign if present. Unit not required however if wrong unit given do not award mark for final answer.eg kJ-1 or kg. Accept kj, kJ, Kj or KJ. If 25 is divided by 1000 = 0·025 maximum 2 marks Answer in joules is accepted but the units must be given. ie 2 090 000 J is acceptable. 2 090 000 on its own is not acceptable.

Question Answer Max Mark Additional Guidance (d) Produces SO2 / acidic gases /

oxides of sulfur

Produces acid rain

1

Zero marks - for produces pollution / toxic or poisonous gases / not environmentally friendly/ flammable on their own but do not negate correct answer

Page sixteen

Question Answer Max Mark Additional Guidance 10. (a) (i) The higher/lower the number of

carbon atoms the higher/lower the flash point The flash point increases/decreases as the number of carbon atoms increases/decreases

1

Cause and effect must be stated correctly Zero marks for: The higher/lower the flash point the higher/lower the number of carbons The number of carbons increases/decreases as the flash point increases/decreases Accept as alternatives increases - goes up/gets higher decreases - goes down/gets lower/less Answer must specifically relate to the number of carbon atoms or length of carbon chain, not to the size of the hydrocarbon molecule. eg accept as the length of the carbon chain increases…. Do not accept as the hydrocarbon gets bigger….

(a) (ii) 47 – 51 inclusive (units not required)

1

Page seventeen

Question Answer Max Mark Additional Guidance (b) 99 with no working (3)

32/128 = 0�25 (1) 0�25 gives 2�25 (9 x 0�25) (1) (this step on its own 2 marks) 2�25 x 44 = 99 (1) (this step on its own 3 marks) ---------------------------------------- 128 g and 44 g both shown (1) 128 g gives 396 g (9 x 44) (1) (this step on its own 2 marks) 32 g gives 99 g [(396/128) x 32] (1) (this step on its own 3 marks) -------------------------------------- 128 g and 44 g both shown (1) 128 g gives 396 g (9 x 44) (1) (this step on its own 2 marks) 128/32 = 4 396/4 = 99 (1) (this step on its own 3 marks) Any other valid method accepted.

3

32/96 ( mass of nonane incorrect) = 0�33 zero marks 0�33 x 9 = 2�97 1 mark correct follow through 2�97 x 44 = 130�68 1 mark correct follow This would be awarded 2 out of 3 marks ---------------------------------------- Any other answer without working = zero marks Unit not required however if wrong unit given do not award mark for final answer. If candidate uses incorrect mass for 9 moles CO2 and has clearly shown working for this step maximum 2 marks can be awarded. If candidate uses incorrect mass for 9 moles of CO2 and has shown no working for this step maximum of 1 mark can be awarded. This also applies to GFM of nonane.

Page eighteen

Question Answer Max Mark Additional Guidance 11. (a) 2Cl- Cl2 + 2e-

or 2Cl- - 2e- Cl2

1

Ignore state symbols if given / state symbols not required Do not need negative sign on electron Negative sign must be shown on chloride ion

(b) (i) sodium hydroxide or sodium oxide

1

Accept correct formula If charges shown they must be correct

(ii) Water is the only product Hydrogen is infinite/renewable Doesn’t produce greenhouse gases / CO2 / CO The products/gases produced do not contribute to the greenhouse effect/global warming Fossil fuels not being used up as fuel

1

Zero marks - environmental friendly / safer / less pollution / less soot Does not produce / toxic gases / harmful gases / SO2 / acid rain Mention of contribution to global warming/greenhouse effect without referring to the combustion products/gases produced would not be awarded a mark These are not acceptable on their own but do not negate

(c) 1

Cl

C

Cl

O

Page nineteen

Question Answer Max Mark Additional Guidance 12. (a) Reduction 1

Redox - zero marks

(b) 70 with no working (3)

GFM = 160g (1) 112 / 160 x 100 (1) = 70 (1)

3

If atomic numbers are used with working shown (68�4 %) maximum 2 marks 68�4 on its own – 0 marks Allow follow through If candidate correctly calculates percentage of oxygen (30%) rather than iron maximum 2 marks but working must be shown 30% on its own zero marks Unit not required however if wrong unit given do not award mark for final answer.

(c) Electrolysis Or correct description eg passing electricity through it

1

Electricity on its own is awarded zero marks heating with carbon negates correct answer heating negates the correct answer unless it is clear that this is used to melt the ore

Page twenty

Question Answer Max Mark Additional Guidance 13. (a) 16 1

Unit not required however if wrong unit given do not award mark for final answer.

(b) 0·08 with no working 3 marks 0·1 x 0·016 = 0·0016 (1)

0·0016/2 = 0·0008 (1) 0·0008/0·01 = 0·08 (1)

0·08 on its own 3 marks or 0·1 x 16 = C2 x 10 (1) 2 1 0·8 = C2 x 10 (1) C2 = 0·08 (1) or any alternative correct method

3

Allow follow through from part (a) For the first method shown candidates should not be penalised if 16 (or volume from part a) and 10 (volume of sodium carbonate solution) are both expressed in cm3. If candidate only calculates number of moles of acid the volume must be in litres to be awarded 1 mark. If candidate correctly divides their number of moles of acid by 2 the mark for the mole ratio can be awarded. Unit not required however if wrong unit given do not award mark for final answer. Accept mol l-1 or mol/l but not mol/l-1 or mol-1 or mol l If concentration of incorrect chemical is calculated then max= 1 mark

Page twenty-one

Question Answer Max Mark Additional Guidance 14. This is an open ended question

1 mark: The student has demonstrated a limited understanding of the chemistry involved. The candidate has made some statement(s) which is/are relevant to the situation, showing that at least a little of the chemistry within the problem is understood. 2 marks: The student has demonstrated a reasonable understanding of the chemistry involved. The student makes some statement(s) which is/are relevant to the situation, showing that the problem is understood. 3 marks: The maximum available mark would be awarded to a student who has demonstrated a good understanding of the chemistry involved. The student shows a good comprehension of the chemistry of the situation and has provided a logically correct answer to the question posed. This type of response might include a statement of the principles involved, a relationship or an equation, and the application of these to respond to the problem. This does not mean the answer has to be what might be termed an “excellent” answer or a “complete” one.

3

[END OF MARKING INSTRUCTIONS]

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