Required chemicals for OCR PAG activities

OCR has produced three example activities for each PAG, comprising student sheets and teacher/technician guidance. Centres may use these directly in their centres, adapt them to their requirements, or merely use them as reference for the types of activity that would satisfy the criteria for each PAG and the Endorsement as a whole.

If you are using some or all of OCR’s PAG activities, this document is intended to act as a useful reference for the chemicals required. These are provided as a stand-alone list, as well as listed by PAG, so if you’re not using all the activities you can still see which chemicals are required. Links are also provided to CLEAPSS HazCards for all chemicals identified.

For more details on the requirements of the practical endorsement, see OCR’s practical skills handbook: http://www.ocr.org.uk/Images/208932-practical-skills-handbook.pdf

The full pupil and teacher sheets for PAG activities are available through Interchange.

© OCR 2017 1 v1.0 – 10 October 2017

Contents

1. List of chemicals required for all PAG activities 2. PAG 1.1 – Determination of the composition of copper(II) carbonate basic 3. PAG 1.2 – Determination of the relative atomic mass of magnesium 4. PAG 1.3 – Determination of the formula for magnesium oxide 5. PAG 2.1 – Determination of the concentration of hydrochloric acid 6. PAG 2.2 – Determination of the molar mass of an acid 7. PAG 2.3 – Identification of an unknown carbonate 8. PAG 3.1 – Determination of the enthalpy change of neutralisation 9. PAG 3.2 – Determination of the enthalpy change of a reaction by Hess’ Law 10. PAG 3.3 – Determination of enthalpy changes of combustion 11. PAG 4.1 – Identifying unknowns 1 12. PAG 4.2 – Identifying unknowns 2 13. PAG 4.3 – Identifying unknowns 3 14. PAG 5.1 – Synthesis of a haloalkane 15. PAG 5.2 – Preparation of cyclohexene 16. PAG 5.3 – Oxidation of ethanol 17. PAG 6.1 – Synthesis of aspirin 18. PAG 6.2 – Preparation of benzoic acid 19. PAG 6.3 – Preparation of methyl 3-nitrobenzoate 20. PAG 7.1 – Identifying organic unknowns 1 21. PAG 7.2 – Identifying organic unknowns 2 22. PAG 7.3 – Identifying organic unknowns 3 23. PAG 8.1 – Electrochemical cells 1 24. PAG 8.2 – Electrochemical cells 2 25. PAG 8.3 – Electrochemical cells 3 26. PAG 9.1 – The rate of decomposition of hydrogen peroxide 27. PAG 9.2 – The rate of reaction of calcium carbonate and hydrochloric acid 28. PAG 9.3 – The rate of reaction of magnesium and hydrochloric acid 29. PAG 10.1 – Rates – iodine clock 30. PAG 10.2 – Rates – thiosulfate and acid 31. PAG 10.3 – Rates – activation energy 32. PAG 11.1 – pH – problem solving 33. PAG 11.2 – pH – titration curves 34. PAG 11.3 – pH – acids and buffers 35. PAG 12.1 – Investigating iron tablets 36. PAG 12.2 – Investigating the copper content of brass screws 37. PAG 12.3 – Investigating the reaction between potassium manganate(VII) and ethanedioic acid 38. Apparatus likely to be required 39. Apparatus potentially required

© OCR 2017 2 v1.0 – 10 October 2017

List of chemicals required for all OCR PAG activities

The list below gives the different chemicals identified for use in OCR’s PAG activities, and the PAGs in which they appear. Note that required concentrations of some substances vary in different PAG activities, so always check the concentration required.

Risk assessments should be carried out for all practical activities; to assist in this, clicking on the names of the chemicals below will take you to the relevant CLEAPSS HazCard for that chemical.

2-methylpropan-2-ol – PAG: 5.1, 7.2 Ammonia solution – PAG: 4.1, 7.3, 11.1, 11.2 Ammonium chloride solution – PAG: 4.2 Ammonium iron(II) sulfate solution – PAG: 8.1 Barium chloride solid – PAG: 4.1 Barium chloride solution – PAG: 4.2 Brass – PAG: 12.2 Bromine water – PAG: 5.2, 7.1, 7.3 Butan-1-ol – PAG: 3.3 Calcium carbonate solid – PAG: 4.1 Calcium chloride solid – PAG: 5.2 Citric acid monohydrate – PAG: 2.2, 7.3 Copper(II) carbonate basic solid – PAG: 1.1 Copper sulfate(VI) solution – PAG: 8.1, 8.2, 8.3 Cyclohexane – PAG: 7.1 Cyclohexene – PAG: 7.1, 7.3 Cyclohexanol – PAG: 5.2 D-glucose – PAG: 7.3 Dipotassium peroxidosulfate(VI) solution – PAG: 10.1 Ethanedioic acid solution – PAG: 10.3, 12.3 Ethanoic acid – PAG: 11.1, 11.2, 11.3, 12.2 Ethanol – PAG: 3.3, 5.3, 6.2, 6.3, 7.2 Glycerol – PAG: 7.3 Heptane – PAG: 7.1 Hydrochloric acid – PAG: 2.1, 2.3, 3.1, 3.2, 5.1, 6.1, 6.2, 9.2, 9.3, 10.2, 11.1, 11.2, 11.3 Hydrogen peroxide – PAG: 9.1 Iron(III) chloride solution – PAG: 7.3, 8.1 Iron(II) sulfate(VI) solution – PAG: 8.2, 8.3 Iron tablets – PAG: 12.1 Limonene – PAG: 7.1 Magnesium ribbon – PAG: 1.2, 1.3, 8.2, 8.3, 9.3 Magnesium sulfate(VI) solution – PAG: 8.2, 8.3 Manganese(IV) oxide solid – PAG: 9.1 Marble chips (calcium carbonate) – PAG: 9.2 Methanoic acid – PAG: 11.1 Methanol – PAG: 3.3

© OCR 2017 3 v1.0 – 10 October 2017

Methylbenzoate – PAG: 6.2, 6.3 Methyl orange indicator – PAG: 2.1, 2.3, 6.2 Nitric acid – PAG: 4.1, 4.2, 4.3, 5.1, 6.3, 12.2 Oil of wintergreen – PAG: 6.1 Pentan-1-ol – PAG: 3.3 Phenolphthalein indicator – PAG: 2.2, 11.1 Phosphoric acid – PAG: 5.2 Potassium carbonate solid – PAG: 3.2 Potassium chromate(VI) solution – PAG: 4.1, 5.3 Potassium dichromate(VI) solution (acidified) – PAG: 5.3, 7.2, 7.3 Potassium hydrogen carbonate solid – PAG: 3.2 Potassium iodide solution – PAG: 4.3, 10.1, 12.2 Potassium manganate(VII) solution – PAG: 10.3, 12.1, 12.3 Potassium nitrate(V) solution – PAG: 8.1, 8.2, 8.3 Propan-1-ol – PAG: 3.3 Propan-2-ol – PAG: 7.2 Salicylic acid – PAG: 7.3 Silver nitrate solution – PAG: 4.1, 4.2, 5.1, 7.3 Sodium carbonate solid – PAG: 2.3, 5.3 Sodium carbonate solution – PAG: 4.2, 4.3, 7.3, 12.2 Sodium chloride solution – PAG: 4.2, 4.3, 5.2 Sodium dichromate(VI)-2-water – PAG: 5.3 Sodium ethanoate solution – PAG: 11.1, 11.3 Sodium hydrogen carbonate solid (analytical grade) – PAG: 2.1 Sodium hydrogen carbonate solution – PAG: 5.1 Sodium hydroxide solution – PAG: 2.2, 3.1, 4.2, 6.1, 6.2, 7.3, 11.1, 11.2, 11.3 Sodium sulfate(VI) solid – PAG: 5.1 Sodium sulfate (VI) solution – PAG: 4.2 Sodium thiosulfate solution – PAG: 10.1, 10.2, 12.2 Starch solution – PAG: 10.1, 12.2 Sulfuric acid – PAG: 1.1, 1.2, 4.1, 5.3, 6.3, 11.1, 12.1, 12.3 Tartaric acid – PAG: 7.3 Universal indicator solution – PAG: 5.3 Zinc sulfate(VI) solution – PAG: 8.3

Back to top

© OCR 2017 4 v1.0 – 10 October 2017

PAG 1.1 – Determination of the composition of copper(II) carbonate basic

Label Identity Hazard information

CuCO3·Cu(OH)2(s)

copper(II) carbonate basic solid, CuCO3·Cu(OH)2(s)

Each learner or group will require approximately 1.5 g

Harmful if swallowed

H2SO4(aq)

1.0 mol dm–3 aqueous sulfuric(VI) acid, H2SO4(aq)

Each learner or group will require 50 cm3

WARNING

Causes skin irritation and serious eye irritation

Back to top

Back to chemicals list

© OCR 2017 5 v1.0 – 10 October 2017

PAG 1.2 – Determination of the relative atomic mass of magnesium

Label Identity Hazard information

1.0 mol dm–3 H2SO4(aq)

1.0 mol dm–3 aqueous sulfuric(VI) acid, H2SO4(aq)

Each learner or group will require 10 cm3.

WARNING

Causes skin irritation and serious eye irritation

Mg(s)

magnesium ribbon

Each learner or group will require approximately 0.12–0.16 g

Currently not classified as hazardous in this form

Back to top

Back to chemicals list

© OCR 2017 6 v1.0 – 10 October 2017

PAG 1.3 – Determination of the formula of magnesium oxide

Label Identity Hazard information

Mg(s)

magnesium ribbon

Each learner will require 8–10 cm

Currently not classified as hazardous in this form

Back to top

Back to chemicals list

© OCR 2017 7 v1.0 – 10 October 2017

PAG 2.1 – Determination of the concentration of hydrochloric acid

Label Identity Hazard information

NaHCO3(s)

sodium hydrogen carbonate solid, NaHCO3(s)

Each learner or group will require 2.5 g so that they can accurately measure 2.10 g to use for their standard solution.

Analytical Grade (AG) sodium hydrogencarbonate is required to ensure high purity – standard grade tends to be <99% pure.

Currently not classified as hazardous

HCl (aq)

0.110 mol dm–3 aqueous hydrochloric acid, HCl(aq)

Each learner or group will require about 150 cm3.

Currently not classified as hazardous at this concentration

H2O(l)

distilled/deionised water, H2O(l)

Each learner or group will require about 300 cm3.

No hazard classification

methyl orange indicator

0.04% methyl orange indicator solution

Currently not classified as hazardous at this concentration. Technicians preparing solutions should note that the methyl orange solid is TOXIC.

Back to top

Back to chemicals list

© OCR 2017 8 v1.0 – 10 October 2017

PAG 2.2 – Determination of the molar mass of an acid

Label Identity Hazard information

Unknown hydrated acid

Citric acid monohydrate solid, C6H8O7H2O(s)

Each learner will require between 1.9–2.1g in a stoppered weighing bottle. A freshly opened stock bottle should be used.

WARNING

Causes serious eye irritation and skin irritation. May cause respiratory irritation.

NaOH(aq)

0.100 mol dm3 aqueous sodium hydroxide, NaOH(aq)

Each learner will require about 150 cm3.

Currently not classified as hazardous at this concentration

Phenolphthalein indicator solution

0.1% phenolphthalein indicator solution

WARNING

Highly flammable

See CLEAPSS Recipe Book 46

Back to top

Back to chemicals list

© OCR 2017 9 v1.0 – 10 October 2017

PAG 2.3 – Identification of an unknown carbonate

Label Identity Hazard information

X2CO3(s)

sodium carbonate solid, Na2CO3(s)

Each learner or group will require between 1.2–1.4 g in a stoppered weighing bottle.

WARNING

Causes serious eye irritation

HCl (aq)

0.100 mol dm–3 aqueous hydrogen chloride acid, HCl(aq)

Each learner will require about 150 cm3.

Currently not classified as hazardous at this concentration

methyl orange indicator

0.04% methyl orange indicator

Currently not classified as hazardous at this concentration

See CLEAPSS Recipe Book 46 – Methyl orange solid is TOXIC.

Back to top

Back to chemicals list

© OCR 2017 10 v1.0 – 10 October 2017

PAG 3.1 – Determination of the enthalpy change of neutralisation

Label Identity Hazard information

HCl (aq)

1.00 mol dm–3 aqueous hydrochloric acid, HCl(aq)

Each learner or group will require about 50 cm3

Currently not classified as hazardous at this concentration

NaOH(aq)

1.0 mol dm3 aqueous

sodium hydroxide, NaOH(aq)

Each learner or group will require about 50 cm3

DANGER

Causes severe skin burns and eye damage

Wear splash-proof goggles

Back to top

Back to chemicals list

© OCR 2017 11 v1.0 – 10 October 2017

PAG 3.2 – Determination of an enthalpy change of reaction by Hess’ Law

Label Identity Hazard information

HCl(aq)

2.00 mol dm–3 aqueous hydrochloric acid, HCl(aq)

Each learner or group will require 2 × 30 cm3

Currently not classified as hazardous at this concentration

K2CO3(s)

potassium carbonate solid, K2CO3(s)

Each learner or group will require between 2.5–3.0 g

WARNING

Causes serious eye irritation

KHCO3(s)

potassium hydrogen carbonate solid, KHCO3(s)

Each learner or group will require between 3.2–3.7 g

Currently not classified as hazardous

Back to top

Back to chemicals list

© OCR 2017 12 v1.0 – 10 October 2017

PAG 3.3 – Determination of enthalpy changes of combustion

Label Identity Hazard information

methanol methanol, CH3OH(l)

DANGER

Highly flammable liquid & vapour. Toxic if swallowed. Toxic in contact with skin. Toxic if inhaled. Causes damage to organs if swallowed, if inhaled and through contact with the skin.

ethanol ethanol, C2H5OH(l)

DANGER

Highly flammable liquid and vapour.

IDA is also: Harmful if swallowed. May cause damage to organs.

propan-1-ol propan-1-ol, C3H7OH(l)

DANGER

Highly flammable liquid and vapour. Causes serious eye damage. May cause drowsiness or dizziness.

butan-1-ol butan-1-ol, C4H9OH(l) DANGER

Flammable liquid and vapour. Causes skin irritation. Causes serious eye damage. May cause respiratory irritation or drowsiness or dizziness. Butan-1-ol is also: Harmful if swallowed.

© OCR 2017 13 v1.0 – 10 October 2017

Label Identity Hazard information

pentan-1-ol pentan-1-ol, C5H11OH(l) Flammable. Harmful by inhalation.

Back to top

Back to chemicals list

© OCR 2017 14 v1.0 – 10 October 2017

PAG 4.1 – Identifying unknowns 1

LabelIdentity / amount required per

learner or groupHazard information

A (for PAG4.1)

A mixture of barium chloride solid, BaCl2(s) and calcium carbonate solid, CaCO3(s) (see note below)

Each learner or group should be provided with about 1.0 g of a mixture containing about 0.3 g of BaCl2·2H2O and 0.7 g of CaCO3.

A large quantity of the mixture should be prepared which can be dispensed to learners.

DANGER

Toxic if swallowed. Harmful if inhaled.

0.4 mol dm-3 HNO3(aq)

0.4 mol dm–3 aqueous nitric acid, HNO3(aq)

ca. 15–20 cm3

WARNING

Causes skin irritation and serious eye irritation

0.05 mol dm-3 AgNO3(aq)

0.05 mol dm–3 aqueous silver nitrate(V), AgNO3(aq)

ca. 10 drops

Currently not classified as hazardous at this concentration

Solutions cause skin to blacken and will stain clothing and some bench surfaces.

1.0 mol dm-3 NH3(aq)

1.0 mol dm–3 aqueous ammonia, NH3(aq)

ca. 15–20 cm3

Causes skin and eye irritation

Ensure room is well ventilated

Avoid inhaling vapour

1.0 mol dm-3 H2SO4(aq)

1.0 mol dm–3 aqueous sulfuric(VI) acid, H2SO4(aq)

ca. 2–3 cm3

WARNING

Causes skin irritation and serious eye irritation

0.1 mol dm-3 K2CrO4(aq)

0.1 mol dm–3 aqueous potassium chromate(VI), K2CrO4(aq)

ca 2–3 cm3

DANGER

May cause: genetic defects; cancer by inhilation

May cause an allergic skin reaction

© OCR 2017 15 v1.0 – 10 October 2017

LabelIdentity / amount required per

learner or groupHazard information

Wear splash-resistant goggles

Wear chemical-resistant gloves

Back to top

Back to chemicals list

© OCR 2017 16 v1.0 – 10 October 2017

PAG 4.2 – Identifying unknowns 2

Label Identity Hazard information

A (for PAG 4.2)1.0 mol dm–3 aqueous sodium chloride, NaCl(aq)

Currently not classified as hazardous, but for the sake of the practical label as

B (for PAG 4.2)1.0 mol dm–3 aqueous ammonium chloride, NH4Cl(aq)

Currently not classified as hazardous

C (for PAG 4.2)1.0 mol dm–3 aqueous sodium sulfate(VI), Na2SO4(aq)

Currently not classified as hazardous

D (for PAG 4.2)1.0 mol dm–3 aqueous sodium carbonate, Na2CO3(aq)

WARNING

Causes serious eye irritation

HNO3(aq)1.0 mol dm3 aqueous nitric acid, HNO3(aq)

DANGER

Causes severe skin burns and eye damage

Wear splash-proof goggles/face shield

AgNO3(aq)0.05 mol dm–3 aqueous silver nitrate(V), AgNO3(aq)

Currently not classified as hazardous at this concentration

Solutions cause skin to blacken and will stain clothing and some bench surfaces.

BaCl2(aq)0.2 mol dm3 aqueous barium chloride, BaCl2(aq)

Currently not classified as hazardous at this concentration

NaOH(aq)0.4 mol dm3

aqueous sodium hydroxide, NaOH(aq)

WARNING

Causes skin irritation and serious eye irritation

Back to top

Back to chemicals list

© OCR 2017 17 v1.0 – 10 October 2017

PAG 4.3 – Identifying unknowns 3

Label Identity Hazard information

A (for PAG 4.3)1.0 mol dm–3 aqueous sodium chloride, NaCl(aq)

Currently not classified as hazardous, but for the sake of the practical label as

WARNING

Causes skin irritation and serious eye irritation

B (for PAG 4.3)1.0 mol dm–3 aqueous potassium iodide, KI (aq)

Currently not classified as hazardous, but for the sake of the practical label as

WARNINGCauses skin irritation and serious eye irritation

C (for PAG 4.3)0.4 mol dm–3 aqueous nitric acid, HNO3(aq)

WARNINGCauses skin irritation and serious eye irritation

D (for PAG 4.3)0.05 mol dm–3 aqueous silver nitrate(V), AgNO3(aq)

Solutions cause skin to blacken and will stain clothing and some bench surfaces.

Currently not classified as hazardous at this concentration, but for the sake of this practical label as:

WARNING

Causes skin irritation and serious eye irritation

E (for PAG 4.3)1.0 mol dm–3 aqueous sodium carbonate, Na2CO3(aq)

WARNING

Causes serious eye irritation… but for the sake of this practical, label as:

WARNING: Causes skin irritation and serious eye irritation

Back to top

Back to chemicals list

© OCR 2017 18 v1.0 – 10 October 2017

PAG 5.1 – Synthesis of a haloalkane

LabelIdentity / amount required

per learner or groupHazard information

2-methylpropan-2-ol

2-methylpropan-2-ol, CH3CH(CH3)ClCH3(l)

c. 6.5 cm3 (5 g).

Note: 2-methylpropan-2-ol has a melting temperature of 25.5C – ensure it has melted before supplying the learners.

DANGER

Highly flammable liquid and vapour. Causes serious eye irritation. Harmful if inhaled. May cause respiratory irritation.

conc. HCl(aq)

concentrated hydrochloric acid, HCl(aq)

c. 20 cm3

DANGER

Causes severe skin burns and eye damage. May cause respiratory irritation.

Wear splash-proof goggles/face shield

Wear chemical resistant gloves

5% NaHCO3(aq)

5% w/v sodium hydrogencarbonate solution, NaHCO3(aq)

c. 50 cm3

Currently not classified as hazardous

Na2SO4(s)

anhydrous sodium sulfate(VI) solid, Na2SO4(s)

c. 3 g

Currently not classified as hazardous

HNO3(aq)

0.4 mol dm–3 aqueous nitric acid, HNO3(aq)

a few drops

WARNING

Causes skin irritation and serious eye irritation

AgNO3(aq)

0.05 mol dm–3 aqueous silver nitrate, AgNO3(aq)

a few drops

Currently not classified as hazardous at this concentration

Solutions cause skin to blacken and will stain clothing and some bench surfaces.

Back to top

Back to chemicals list

© OCR 2017 19 v1.0 – 10 October 2017

PAG 5.2 – Preparation of cyclohexene

LabelIdentity / amount required

per learner or groupHazard information

cyclohexanol

cyclohexanol, C6H11OH

c. 10 cm3

Note: Cyclohexanol has a melting point of 26C – ensure it has melted before supplying the learners.

Harmful by inhalation and if swallowed. Irritating to respiratory system and skin.

conc. H3PO4(aq)85% (w/w) phosphoric(V) acid (orthophosphoric acid)

c. 4 cm3

DANGER

Causes severe skin burns and eye damage

Wear splash-proof goggles/face shield

Wear chemical resistant gloves

sat. NaCl(aq)

saturated sodium chloride solution, NaCl(aq)

c. 15 cm3

Currently not classified as hazardous at this concentration

CaCl2(s)anhydrous calcium chloride, CaCl2(s)

c. 2-3 g

WARNING

Causes serious eye irritation

Br2(aq)

<0.06 mol dm–3 bromine water, Br2(aq)

c. a few drops

Currently not classified as hazardous at this concentration

Back to top

Back to chemicals list

© OCR 2017 20 v1.0 – 10 October 2017

PAG 5.3 – Oxidation of ethanol

LabelIdentity / amount required

per learner or groupHazard information

ethanolethanol, C2H5OH(l)

ca. 2 cm3

DANGER

Highly flammable liquid and vapour.

IDA is also: Harmful if swallowed. May cause damage to organs.

Na2Cr2O7·2H2O(s)

Sodium dichromate(VI)-2-water, Na2Cr2O7·2H2O(s)

2.0 g and 4.0 g separately preweighed in weighboats/sample tubes

DANGER

May intensity fire; oxidiser. Toxic if swallowed. Harmful in contact with skin. Causes severe skin burns and eye damage. May cause an allergic skin reaction. Fatal if inhaled. May cause allergy or asthma symptoms or breathing difficulties if inhaled. May cause genetic defects. May cause cancer. May damage fertility. May damage the unborn child. Causes damage to organs through prolonged or repeated exposure. Very toxic to aquatic life with long lasting effects.

Wear splash-proof goggle.

Wear chemical-resistant gloves.

2.0 mol dm–3 H2SO4(aq)

2.0 mol dm–3 aqueous sulfuric(VI) acid, H2SO4(aq)

ca.20 cm3

WARNING

Causes skin irritation and serious eye irritation

3.0 mol dm–3 H2SO4(aq)

3.0 mol dm–3 aqueous sulfuric(VI) acid, H2SO4(aq)

ca.20 cm3

WARNING

Causes skin irritation and serious eye irritation

© OCR 2017 21 v1.0 – 10 October 2017

LabelIdentity / amount required

per learner or groupHazard information

Na2CO3(s)

sodium carbonate solid, Na2CO3(s)

ca. 0.5 g

WARNING

Causes serious eye irritation

universal indicator solution

< 1% w/v commercial formulation or follow CLEAPSS Recipe Book #47.

ca. a few drops

FLAMMABLE if made up in 50:50 ethanol:water

acidified 0.100 mol dm–3 K2Cr2O7(aq)

0.100 mol dm–3 potassium dichromate(VI), K2Cr2O7(aq), made up in 0.100 mol dm–3 sulfuric(VI) acid, H2SO4(aq)

ca. a few drops

DANGER

May cause allergic skin reactions; allergy / asthma symptoms / breathing difficulties if inhaled; cancer; genetic defects. May damage the unborn child.

Causes skin irritation and serious eye irritation. May cause damage to organs through prolonged or repeated exposure.

Causes severe skin burns and eye damage. Harmful if swallowed. May cause respiritatory irritation.

Wear splash-proof goggle.

Wear chemical-resistant gloves.

Back to top

Back to chemicals list

© OCR 2017 22 v1.0 – 10 October 2017

PAG 6.1 – Synthesis of aspirin

LabelIdentity / amount required

per learner or groupHazard information

oil of wintergreen

oil of wintergreen (98% methyl 2-hydroxybenzoate)

ca 2.5 g

WARNING

Causes skin irritation, serious eye irritation and may cause respiratory irritation.

2.0 mol dm-3 NaOH(aq)

2.0 mol dm3 aqueous

sodium hydroxide, NaOH(aq)

ca. 25 cm3

DANGER

Causes severe skin burns and eye damage

Wear splash-proof goggles

2.00 mol dm-3 HCl(aq)

2.00 mol dm–3 aqueous hydrochloric acid, HCl(aq)

ca. 5 cm3

Currently not classified as hazardous at this concentration

Back to top

Back to chemicals list

© OCR 2017 23 v1.0 – 10 October 2017

PAG 6.2 – Preparation of benzoic acid

LabelIdentity / amount required

per learner or groupHazard information

methyl benzoate

methyl benzoate, C6H5COOCH3(l)

c. 2 cm3

WARNING

Harmful if swallowed. May cause skin irritation and serious eye irritation.

2.0 mol dm–3 NaOH(aq)

2.0 mol dm3 aqueous

sodium hydroxide, NaOH(aq)

c. 10 cm3

DANGER

Causes severe skin burns and eye damage

Wear splash-proof goggles

2.00 mol dm–3 HCl(aq)

2.00 mol dm–3 aqueous hydrochloric acid, HCl(aq)

c. 20 cm3

Currently not classified as hazardous at this concentration

Ethanolethanol, C2H5OH(l)

c. 10 cm3

DANGER

Highly flammable liquid and vapour.

IDA is also: Harmful if swallowed. May cause damage to organs.

methyl orange indicator

0.1% methyl orange indicator

Currently not classified as hazardous at this concentration

See CLEAPSS Recipe Book 46

Back to top

Back to chemicals list

© OCR 2017 24 v1.0 – 10 October 2017

PAG 6.3 – Preparation of methyl 3-nitrobenzoate

LabelIdentity / amount required

per learner or groupHazard information

methyl benzoate

methyl benzoate, C6H5COOCH3(l)

c. 2.5 cm3

WARNING

Harmful if swallowed. May cause skin irritation and serious eye irritation.

conc. H2SO4

concentrated sulfuric(VI) acid, H2SO4(aq)

c. 7 cm3

DANGER

Causes severe skin burns and eye damage

Wear splash-proof goggles/face shield

conc. HNO3

concentrated nitric(V) acid, HNO3(aq)

c. 2 cm3

DANGER

Causes severe skin burns and eye damage

May intensify fire; oxidiser

Wear splash-proof goggles/face shield

Wear chemical resistant gloves

ethanolethanol, C2H5OH(l)

c. 15 cm3

DANGER

Highly flammable liquid and vapour.

IDA is also: Harmful if swallowed. May cause damage to organs.

Back to top

Back to chemicals list

© OCR 2017 25 v1.0 – 10 October 2017

PAG 7.1 – Identifying organic unknowns 1

LabelIdentity / amount

required per learner or group

Hazard information

heptaneheptane, C7H16(l)

c. 1 drop

DANGER

Highly flammable liquid and vapour. May be fatal if swallowed and enters airways. May cause drowsiness or dizziness. Causes skin irritation. Very toxic or toxic to aquatic life with long lasting effects.

cyclohexanecyclohexane, C6H12(l)

c. 1 drop

DANGER

May be fatal if swallowed and enters airways. May cause drowsiness or dizziness. Highly flammable liquid and vapour. Causes skin irritation. Very toxic or toxic to aquatic life with long lasting effects.

cyclohexenecyclohexene, C6H10(l)

c. 1 drop

DANGER

Highly flammable liquid and vapour. Harmful if swallowed. May be fatal if swallowed and enters airways. Toxic to aquatic life with long lasting effects.

limonenelimonene, C10H16(l)

c. 1 drop

WARNING

Flammable liquid and vapour. Causes skin irritation. May cause allergic skin reaction. Very toxic to aquatic life with long lasting effects.

Br2(aq)<0.06 mol dm–3 bromine water, Br2(aq)

c. 2 cm3

Currently not classified as hazardous at this concentration

Back to top

Back to chemicals list

© OCR 2017 26 v1.0 – 10 October 2017

PAG 7.2 – Identifying organic unknowns 2

LabelIdentity / amount required

per learner or groupHazard information

ethanolethanol, CH3CH2OH(l)

c. 3 drops

DANGER

Highly flammable liquid and vapour.

IDA is also: Harmful if swallowed. May cause damage to organs.

propan-2-ol

propan-2-ol, CH3CHOHCH3(l)

c. 3 drops

DANGER

Highly flammable liquid and vapour. Causes serious eye damage. May cause drowsiness or dizziness.

2-methylpropan-2-ol

2-methylpropan-2-ol, (CH3)3COH(l)

c. 3 drops

DANGER

Highly flammable liquid and vapour. Causes serious eye irritation. Harmful if inhaled. May cause respiratory irritation.

acidified 0.100 mol dm–3 K2Cr2O7(aq)

0.100 mol dm–3 aqueous potassium dichromate(VI), K2Cr2O7(aq), in 1.4 mol dm–3 sulfuric(VI) acid, H2SO4(aq)

c. 20 drops

DANGER

May cause allergic skin reactions; allergy / asthma symptoms / breathing difficulties if inhaled; cancer; genetic defects. May damage the unborn child.

Causes skin irritation and serious eye irritation. May cause damage to organs through prolonged or repeated exposure.

Causes severe skin burns and eye damage. Harmful if swallowed. May cause respiritatory irritation.

Back to top

Back to chemicals list

© OCR 2017 27 v1.0 – 10 October 2017

PAG 7.3 – Identifying organic unknowns 3

LabelIdentity / amount required

per learner or groupHazard information

A–F (for PAG 7.3)

Separate samples of compounds A–F for PAG7.3

c. 1 g per compound

DANGER

Each compound has different hazards.

Assume all are:

Harmful if swallowed and in contact with the skin. May be fatal if swallowed and enters airways. May cause an allergic skin reaction. Cause serious eye damage. Cause respiratory irritation.

Assume liquids are:

Highly flammable liquid and vapour.

Toxic to aquatic life with long lasting effects.

A (for PAG 7.3) D-glucose, C6H12O6(s) Currently no hazard classification

B (for PAG 7.3)citric acid monohydrate, C6H8O7H2O(s)

WARNING

Causes serious eye irritation and skin irritation. May cause respiratory irritation.

C (for PAG 7.3)tartaric acid (2,3-dihydrobutanedioic acid), HOOCCH(OH)CH(OH)COOH(s)

WARNING

Causes serious eye irritation. Causes skin irritation. May cause respiratory irritation.

© OCR 2017 28 v1.0 – 10 October 2017

LabelIdentity / amount required

per learner or groupHazard information

D (for PAG 7.3)salicylic acid (2-hydroxybenzoic acid), HOC6H4COOH(s)

DANGER

Harmful if swallowed. Causes serious eye damage.

E (for PAG 7.3)glycerol, CH2OHCH(OH)CH2OH(l)

Currently no hazard classification

F (for PAG 7.3) cyclohexene, C6H10(l)

DANGER

Highly flammable liquid and vapour. Harmful if swallowed. May be fatal if swallowed and enters airways. Toxic to aquatic life with long lasting effects.

0.500 mol dm–3 Na2CO3(aq)

0.500 mol dm–3 aqueous sodium carbonate, Na2CO3(aq)

c. 10 cm3

Currently not classified as hazardous at this concentration

0.4 mol dm–3 NaOH(aq)

0.4 mol dm3 aqueous sodium

hydroxide, NaOH(aq)

c. 1 cm3

WARNING

Causes skin irritation and serious eye irritation

1.0 mol dm–3 NH3(aq)

1.0 mol dm–3 aqueous ammonia, NH3(aq)

c. 4 cm3

WARNINGCauses skin and eye irritation

Ensure room is well ventilated

Avoid inhaling vapour

© OCR 2017 29 v1.0 – 10 October 2017

LabelIdentity / amount required

per learner or groupHazard information

2.0 mol dm–3 NH3(aq)

2.0 mol dm–3 aqueous ammonia, NH3(aq)

c. 2 cm3

DANGER

Causes skin irritation and serious eye damage

Ensure room is well ventilated

Avoid inhaling vapour

Wear splash-proof goggles

0.05 mol dm–3 AgNO3(aq)

0.05 mol dm–3 aqueous silver nitrate(V), AgNO3(aq)

c. 2 cm3

Currently not classified as hazardous at this concentration

Solutions cause skin to blacken and will stain clothing and some bench surfaces.

0.1 mol dm–3 FeCl3(aq)

0.1 mol dm–3 aqueous iron(III) chloride, FeCl3(aq)

c. 2 cm3

WARNING

Causes serious eye irritation

acidified 0.100 mol dm–3 K2Cr2O7(aq)

0.100 mol dm–3 aqueous potassium dichromate(VI), K2Cr2O7(aq), in 1.4 mol dm–3 sulfuric(VI) acid, H2SO4(aq)

c. 6 cm3

DANGER

May cause allergic skin reactions; allergy / asthma symptoms / breathing difficulties if inhaled; cancer; genetic defects. May damage the unborn child.

Causes skin irritation and serious eye irritation. May cause damage to organs through prolonged or repeated exposure.

Causes severe skin burns and eye damage. Harmful if swallowed. May cause respiritatory irritation.

Wear splash-proof goggle.

Wear chemical-resistant gloves.

Br2(aq)

<0.06 mol dm–3 bromine water, Br2(aq)

c. 2 cm3

Currently not classified as hazardous at this concentration

© OCR 2017 30 v1.0 – 10 October 2017

Back to top

Back to chemicals list

© OCR 2017 31 v1.0 – 10 October 2017

PAG 8.1 – Electrochemical cells 1

LabelIdentity / amount required

per learner or groupHazard information

0.1 mol dm–3 copper sulfate(VI) solution

0.1 mol dm–3 aqueous copper sulfate(VI) solution, CuSO4(aq)

c. 50 cm3

Currently not classified as hazardous at this concentration

0.1 mol dm–3 ammonium iron(II) sulfate solution

0.1 mol dm–3 aqueous diammonium iron(II) sulfate solution, (NH4)2SO4

FeSO4(aq)

Currently not classified as hazardous at this concentration.

0.1 mol dm–3 FeCl3(aq)

0.1 mol dm–3 aqueous iron(III) chloride, FeCl3(aq)

WARNING

Causes serious eye irritation

A–E (for PAG 8.1)

Mixtures of aqueous ammonium iron(II) sulfate:iron(III) chloride

Volumetric ratios:

A – 1 Fe2+ : 5 Fe3+

B – 1 Fe2+ : 3 Fe3+

C – 1 Fe2+ : 1 Fe3+

D – 3 Fe2+ : 1 Fe3+

E – 5 Fe2+ : 1 Fe3+

c. 50 cm3 from a stock bottle (see below)

WARNING

Causes serious eye irritation.

saturated potassium nitrate(V) solution

saturated aqueous KNO3(aq)

c. 200 cm3 in a wide shallow container for the whole class

Currently not classified as hazardous at this concentration.

Handle the soaked filter papers with tweezers.

Back to top

Back to chemicals list

© OCR 2017 32 v1.0 – 10 October 2017

PAG 8.2 – Electrochemical cells 2

LabelIdentity / amount required

per learner or groupHazard information

1.0 mol dm–3 copper sulfate(VI)

1.0 mol dm–3 aqueous copper sulfate(VI) solution, CuSO4(aq)

c. 50 cm3

WARNING

Harmful if swallowed. Causes skin irritation. Causes serious eye irritation.

1.0 mol dm-3 iron(II) sulfate(VI)

1.0 mol dm–3 aqueous iron(II) sulfate(VI) solution, ZnSO4(aq)

c. 50 cm3

WARNING

Causes serious eye irritation.

1.0 mol dm–3 magnesium sulfate(VI)

1.0 mol dm–3 aqueous magnesium sulfate(VI) solution, MgSO4(aq)

c. 50 cm3

Currently not classified as hazardous

1.0 mol dm-3 zinc sulfate(VI)

1.0 mol dm–3 aqueous zinc sulfate(VI) solution, ZnSO4(aq)

c. 50 cm3

DANGER

Causes serious eye damage.

saturated potassium nitrate(V) solution

saturated aqueous potassium nitrate(V) solution, KNO3(aq)

c. 200 cm3 in a wide shallow container for the whole class

Currently not classified as hazardous at this concentration

magnesium

Magnesium ribbon, Mg(s)

one strip, c. 10 cm piece of ribbon

Currently not classified as hazardous in this form.

Back to top

Back to chemicals list

© OCR 2017 33 v1.0 – 10 October 2017

PAG 8.3 – Electrochemical cells 3

LabelIdentity / amount required

per learner or groupHazard information

0.1 mol dm–3 copper sulfate(VI) solution

0.1 mol dm–3 aqueous copper sulfate(VI) solution, CuSO4(aq)

c. a few drops

Currently not classified as hazardous at this concentration

0.1 mol dm–3 iron(II) sulfate(VI)

0.1 mol dm–3 aqueous iron(II) sulfate(VI) solution, ZnSO4(aq)

c. a few drops

Currently not classified as hazardous at this concentration

0.1 mol dm–3 magnesium sulfate(VI)

1.0 mol dm–3 aqueous magnesium sulfate(VI) solution, MgSO4(aq)

c. a few drops

Currently not classified as hazardous

0.1 mol dm-3 zinc sulfate(VI)

0.1 mol dm–3 aqueous zinc sulfate(VI) solution, ZnSO4(aq)

c. a few drops

WARNING

Causes serious eye damage.

magnesium ribbon

magnesium ribbon (c. 1 cm), Mg(s)

one piece

Currently not classified as hazardous in this form.

saturated potassium nitrate(V) solution

Saturated aqueous potassium nitrate(V) solution, KNO3(aq)

c. a few drops

Currently not classified as hazardous at this concentration

Back to top

Back to chemicals list

© OCR 2017 34 v1.0 – 10 October 2017

PAG 9.1 – The rate of decomposition of hydrogen peroxide

Label Identity Hazard information

H2O2(aq) Aqueous hydrogen peroxide, H2O2(aq), of

concentration 0.167 mol dm–3 (2 volume H2O2).

This solution deteriorates quite rapidly, and so should be made up freshly. Dilute 100 volume H2O2 in distilled or de-ionised water. See

CLEAPSS® guidance.

Each learner or group will require 20 cm3 per experiment.

Currently not classified as hazardous at this concentration.

MnO2(s) Each learner or group will require about 0.05 g per experiment.

WARNING

Harmful if swallowed. Harmful if inhaled.

Back to top

Back to chemicals list

© OCR 2017 35 v1.0 – 10 October 2017

PAG 9.2 – The rate of reaction of calcium carbonate and hydrochloric acid

Label Identity Hazard information

Marble chips Marble chips (calcium carbonate), CaCO3(s).

It is recommended to use the largest size of marble chips that will give a decent rate (reaction complete in 4–5 minutes) to minimise the change in surface area.

Currently not classified as hazardous.

2 mol dm–3 HCl(aq) 2 mol dm–3 aqueous hydrochloric acid, HCl(aq)

Each learner or group will require 20 cm3 per mass loss experiment.

Currently not classified as hazardous at this concentration.

0.5 mol dm–3 HCl(aq) 0.5 mol dm–3 aqueous hydrochloric acid, HCl(aq)

Each learner or group will require 20 cm3 per gas collection experiment.

Currently not classified as hazardous at this concentration.

Back to top

Back to chemicals list

© OCR 2017 36 v1.0 – 10 October 2017

PAG 9.3 – The rate of reaction of magnesium and hydrochloric acid

Label Identity Hazard information

Mg(s) Magnesium ribbon.

Each learner or group will require a piece of mass about 0.08 g for each experiment; if 3 runs are completed as done here 3 pieces will be required.

Currently not classified as hazardous in this form

2.00 mol dm–3 HCl(aq)

2.00 mol dm–3 aqueous hydrochloric acid, HCl(aq).

Each learner or group will require about 20 cm3 at this concentration.

Currently not classified as hazardous at this concentration

1.00 mol dm–3 HCl(aq)

1.00 mol dm–3 aqueous hydrochloric acid, HCl(aq).

Each learner or group will require about 20 cm3 at this concentration.

Currently not classified as hazardous at this concentration

0.500 mol dm–3 HCl(aq)

0.500 mol dm–3 aqueous hydrochloric acid, HCl(aq).

Each learner or group will require about 20 cm3 at this concentration.

Currently not classified as hazardous at this concentration

Back to top

Back to chemicals list

© OCR 2017 37 v1.0 – 10 October 2017

PAG 10.1 – Rates – iodine clock

Label Identity Hazard information

1.00 mol dm–3

KI(aq)Aqueous potassium iodide, KI(aq), 1.00 mol dm–3.

This should be supplied in a stoppered bottle, which may be shared by up to four learners or groups.

50 cm3 per learner or group should be sufficient to run two series of experiments, varying [I–(aq)] and [S2O8

2–] respectively.

Currently not classified as hazardous

0.0400 mol dm–3 K2S2O8(aq)

0.0400 mol dm–3 aqueous dipotassium peroxodisulfate(VI), K2S2O8(aq)

This solution deteriorates on storage and is best made no more than a few days in advance.

50 cm3 per learner or group should be sufficient to run two series of experiments, varying [I–(aq)] and [S2O8

2–(aq)] respectively.

DANGER

May cause respiratory irritation

May cause allergy or asthma symptoms or breathing difficulties if inhaled.

0.0100 mol dm–3

Na2S2O3(aq)0.0100 mol dm–3 aqueous sodium thiosulfate, Na2S2O3(aq)

Each learner or group will require about 10 cm3 per series of experiments (5 runs).

Currently not classified as hazardous

Starch 1% aqueous starch indicator

This ‘solution’ is really a suspension and does not keep. The starch solution should be freshly made up but supplied at room temperature.

This solution is made by mixing 1 g of soluble starch with distilled or de-ionised water to form a thin paste. 80 cm3 of distilled or de-ionised water is then boiled and poured into the starch–water paste. The paste is stirred, allowed to cool and diluted to 100 cm3.

The starch solution should be supplied in a small, stoppered bottle, which may be shared by up to four learners or groups.

Each learner or group will require about 5 cm3 per series of experiments (5 runs).

Currently no hazard classification

Back to top

Back to chemicals list

© OCR 2017 38 v1.0 – 10 October 2017

PAG 10.2 – Rates – thiosulfate and acid

Label Identity Hazard information

0.150 mol dm–3 Na2S2O3(aq)

0.150 mol dm–3 aqueous sodium thiosulfate, Na2S2O3(aq).

Amount required will depend on number of repeats and learners’ decisions regarding dilutions required. About 350 cm3 per learner or group should be sufficient for 1 set of experiments investigating the effect of both [S2O3(aq)] and [HCl(aq)].

Currently not classified as hazardous

2.00 mol dm–3 HCl(aq)

2.00 mol dm–3 aqueous hydrochloric acid, HCl(aq)

Amount required will depend on number of repeats and learners’ decisions regarding dilutions required. About 100 cm3 per learner or group should be sufficient for 1 set of experiments investigating the effect of both [S2O3(aq)] and [HCl(aq)].

Currently not classified as hazardous at this concentration

Water Distilled (or de-ionised) water.

Back to top

Back to chemicals list

© OCR 2017 39 v1.0 – 10 October 2017

PAG 10.3 – Rates – activation energy

Label Identity Hazard information

0.0200 mol dm–3

KMnO4(aq)0.0200 mol dm–3 aqueous potassium manganate, KMnO4(aq).

This solution is made up by dissolving 3.16 g of KMnO4 in distilled or deionised water and made up to 1.00 dm3 of solution. The neutral solution is not stable, so should be prepared about an hour or two before the activity.

Each learner or group will require about 100 cm3.

Currently not classified as hazardous at this concentration.

0.500 mol dm–3 H2C2O4(aq)

0.500 mol dm–3 aqueous ethanedioic acid (oxalic acid), H2C2O4(aq).

This solution is made up by dissolving 63.0 g of H2C2O42H2O in distilled or deionised water and made up to 1.00 dm3 of solution.

Each learner or group will require about 100 cm3.

WARNING Causes serious eye irritation

Water Distilled or de-ionised water. No hazard

Back to top

Back to chemicals list

© OCR 2017 40 v1.0 – 10 October 2017

PAG 11.1 – pH – problem solving

LabelIdentity / amount required

per learner or groupHazard information

A–G (PAG 11.1)

Randomly assign A–G to the seven solutions, and pass the teacher the list.

0.1 mol dm3 aqueous ammonia, NH3(aq)c. 15 cm3

Currently not classified as hazardous at this concentration, but as supplied as an unknown solution, label as:

WARNING

May cause skin and eye irritation

0.1 mol dm–3 ethanoic acid, CH3COOH(aq), 0.1 mol dm–3

c. 15 cm3

Currently not classified as hazardous at this concentration, but as supplied as an unknown solution, label as:

WARNING

May cause skin and eye irritation

ethanoate buffer (0.1 mol dm–3 ethanoic acid CH3COOH (aq) / 0.1 mol dm–3sodium ethanoate, CH3COONa(aq)), (1 : 1)c. 15 cm3

Currently not classified as hazardous at this concentration, but as supplied as an unknown solution, label as:

WARNING

May cause skin and eye irritation

0.1 mol dm–3 aqueous hydrochloric acid, HCl(aq)c. 15 cm3

Currently not classified as hazardous at this concentration, but as supplied as an unknown solution, label as:

WARNING

May cause skin and eye irritation

© OCR 2017 41 v1.0 – 10 October 2017

LabelIdentity / amount required

per learner or groupHazard information

0.1 mol dm–3 aqueous methanoic acid, HCOOH(aq)c. 15 cm3

Currently not classified as hazardous at this concentration, but as supplied as an unknown solution, label as:

WARNINGMay cause skin and eye irritation

0.1 mol dm–3 aqueous sodium hydroxide, NaOH(aq)c. 15 cm3

Currently not classified as hazardous at this concentration, but as supplied as an unknown solution, label as:

WARNINGMay cause skin and eye irritation

0.1 mol dm–3 aqueous sulfuric(VI) acid, H2SO4(aq)c. 15 cm3

Currently not classified as hazardous at this concentration, but as supplied as an unknown solution, label as:

WARNINGMay cause skin and eye irritation

Phenolphthalein indicator solution

0.1% phenolphthalein indicator solutionaccess to a dropper bottle

WARNINGHighly flammableSee CLEAPSS Recipe Book 46

0.4 mol dm–3 NaOH(aq)

0.4 mol dm3 aqueous

sodium hydroxide, NaOH(aq)c. 15 cm3

WARNINGCauses skin irritation and serious eye irritation

0.4 mol dm–3 HCl(aq)

0.4 mol dm–3 aqueous hydrochloric acid, HCl(aq)c. 15 cm3

Currently not classified as hazardous at this concentration

Back to top

Back to chemicals list

© OCR 2017 42 v1.0 – 10 October 2017

PAG 11.2 – pH – titration curves

Label Identity / amount required per learner or group Hazard information

0.1 mol dm–3 HCl(aq)

0.1 mol dm–3 aqueous hydrochloric acid, HCl(aq)

c. 150 cm3

Currently not classified as hazardous at this concentration

0.1 mol dm–3 ethanoic acid

0.1 mol dm3 aqueous ethanoic acid, CH3CO2H(aq)

c. 150 cm3

Currently not classified as hazardous at this concentration

0.1 mol dm–3 NaOH(aq)

0.1 mol dm3 aqueous sodium hydroxide, NaOH(aq)

c. 150 cm3

Currently not classified as hazardous at this concentration

0.1 mol dm–3 NH3(aq)

0.1 mol dm–3 aqueous ammonia, NH3(aq)

c. 150 cm3

Currently not classified as hazardous at this concentration, but recommend labelling as:

WARNINGCauses skin and eye irritationEnsure room is well ventilatedAvoid inhaling vapour

Back to top

Back to chemicals list

© OCR 2017 43 v1.0 – 10 October 2017

PAG 11.3 – pH – acids and buffers

LabelIdentity / amount required

per learner or groupHazard information

0.100 mol dm–3 HCl(aq)

0.100 mol dm–3 aqueous hydrochloric acid, HCl(aq)

c. 10 cm3

Currently not classified as hazardous at this concentration

0.400 mol dm–3 NaOH(aq)

0.400 mol dm3 aqueous

sodium hydroxide, NaOH(aq)

c. 5 cm3

WARNING

Causes skin irritation and serious eye irritation

0.400 mol dm–3 ethanoic acid

0.400 mol dm3 aqueous ethanoic acid, CH3COOH(aq)

c. 60 cm3

Currently not classified as hazardous at this concentration

0.400 mol dm–3

sodium ethanoate

0.400 mol dm–3 aqueous sodium ethanoate, CH3COONa(aq)

c. 60 cm3

Currently not classified as hazardous at this concentration

Back to top

Back to chemicals list

© OCR 2017 44 v1.0 – 10 October 2017

PAG 12.1 – Investigating iron tablets

Label Identity Hazard informationIron tablets Commercial iron tablets.

Usually labelled ‘200 mg’ and containing 65 mg iron in the form of soluble Fe(II) ions.

Each learner or group should be given 5 tablets.

The packaging should be made available to learners so that they can find information regarding the identity and mass of the active ingredient.

Not classified as hazardous

KMnO4(aq) 0.0100 mol dm3 aqueous potassium manganate(VII), KMnO4(aq) in 0.1 mol dm–3 aqueous sulfuric acid, H2SO4(aq).

Solutions are best prepared no more than a few days before use, and should be shielded from light. The solution can be standardised by titration against a standard solution of ethanedioic acid (oxalic acid), and learners given the accurate concentration.

Each learner or group may require up to 100–150 cm3, depending on the chosen method. The solution may have to be diluted to give adequate titration results.

Currently not classified as hazardous at this concentration

H2SO4(aq) 1 mol dm3 (approx.) aqueous sulfuric acid, H2SO4(aq).

Each learner or group may require up to 250 cm3, depending on the chosen method.

WARNINGCauses skin irritation and serious eye irritation

Back to top

Back to chemicals list

© OCR 2017 45 v1.0 – 10 October 2017

PAG 12.2 – Investigating the copper content of brass screws

Label Identity Hazard informationBrass Brass screws.

If learners are dissolving the brass themselves, each learner or group will require about 2.5 g of screws.

The teacher will need 2 g of brass screws for the demonstration.

Not classified as hazardous

c. HNO3 Concentrated nitric acid, HNO3(aq).

This should be provided in a fume cupboard. Around 10 cm3 will be required to dissolve 2.5 g of brass screws.

DANGERCauses severe skin burns and eye damageMay intensify fire; oxidiserWear splash-proof goggles/face shieldWear chemical resistant gloves

Na2CO3(aq) 0.500 mol dm–3 aqueous sodium carbonate, Na2CO3(aq).

Currently not classified as hazardous at this concentration

CH3COOH(aq)

1.00 mol dm–3 aqueous ethanoic acid, CH3COOH(aq).

Currently not classified as hazardous at this concentration

Na2S2O3(aq) 0.100 mol dm–3 aqueous sodium thiosulfate, Na2S2O3(aq).

Each learner or group will require about 150 cm3, depending on their chosen method.

This solution is made up by dissolving 24.82 g of Na2S2O35H2O in distilled or deionised water and making up to 1.00 dm3 of solution.

Currently not classified as hazardous at this concentration

KI(aq) 0.500 mol dm–3 aqueous potassium iodide, KI(aq).

Each learner or group will require about 40 cm3, depending on their chosen method.

This solution is made up by dissolving 83.0 g of KI in distilled or de-ionised water and making up to 1.00 dm3 of solution.

This should be supplied in a stoppered bottle, which may be shared by up to four learners/groups.

Currently not classified as hazardous

Starch Starch indicator solution

This ‘solution’ is really a suspension and does not keep. The starch solution should be freshly made up but supplied at room temperature.

This solution is made by mixing 1 g of soluble starch with distilled or de-ionised water to form a

Currently not classified as hazardous

© OCR 2017 46 v1.0 – 10 October 2017

thin paste. 80 cm3 of distilled or de-ionised water is then boiled and poured into the starch–water paste. The paste is stirred, allowed to cool and diluted to 100 cm3.

The starch solution should be supplied in a small, stoppered bottle, which may be shared by up to four learners/groups.

Dissolved brass

Learners/groups may be issued with pre-prepared samples of dissolved brass, or could prepare samples themselves. See ‘Notes’ for the procedure on how to prepare samples.Each learner or group will require about 100 cm3 of solution, with the mass of the brass dissolved written on the container.

Alternatively, mock ‘dissolved brass’ can be prepared as a solution of copper(II) sulfate of approximate concentration 0.10 mol dm–3. Use a range of values from 2.60–2.80 g as the mass of brass (the actual mass does not matter and it is better if different learners get different titres).

Approximate 0.10 mol dm–3 CuSO4(aq) can made up by dissolving 25.0 g of CuSO45H2O in distilled (or de-ionised) water and making up to 1.00 dm3 of solution.

Pre-prepared samples of dissolved brass should be treated as causing severe skin burns and eye damage.

CuSO4(aq) has no hazard classification at concentration 0.10 mol dm–3.

Back to top

Back to chemicals list

© OCR 2017 47 v1.0 – 10 October 2017

PAG 12.3 – Investigating the reaction between potassium manganate(VII) and ethanedioic acid

Label Identity Hazard information

KMnO4(aq) 0.0200 mol dm–3 aqueous potassium manganate, KMnO4(aq).

This solution is made up by dissolving 3.16 g of KMnO4 in distilled or deionised water and making up to 1.00 dm3 of solution. The neutral solution is not stable, so should be prepared about an hour or two before the activity.

Each learner or group will require about 100 cm3.

Currently no hazard classification at this concentration

H2C2O4(aq) 0.500 mol dm–3 aqueous ethanedioic acid (oxalic acid), H2C2O4(aq).

This solution is made up by dissolving 63.0 g of H2C2O42H2O in distilled or deionised water and making up to 1.00 dm3 of solution.

Each learner or group will require about 100 cm3.

WARNING

Causes serious eye irritation

H2SO4(aq) 1.00 mol dm–3 aqueous sulfuric acid, H2SO4(aq).

Each learner or group will require about 100 cm3.

WARNING

Causes skin irritation and serious eye irritation

Water Distilled or de-ionised water.

This should be supplied in a wash bottle.

Each learner or group will require about 200 cm3.

No hazard

Back to top

Back to chemicals list

© OCR 2017 48 v1.0 – 10 October 2017

Apparatus likely to be required

The following apparatus is likely to be required to complete activities covering all techniques required by the Practical Endorsement in GCE Chemistry (Section 1.2.2 of the specification).

Balance reading to at least two decimal places Stop clocks/watches reading to 1 s or better Beakers (400 cm3, 250 cm3, 100 cm3) Pipettes (25 cm3, 10 cm3) Pipette fillers Burettes (50 cm3) Measuring cylinders (250 cm3, 50 cm3, 25 cm3, 10 cm3) Gas syringes (100 cm3) (can be replaced by inverted burettes, measuring cylinders) Thermometers (−10 to 110 °C or equivalent, accurate to 0.5 °C) Heating apparatus: water baths, or electric heaters, or sand baths. A water bath could consist of a beaker of

water on a tripod and gauze over a Bunsen flame. pH indicator paper, or pH meter, or pH probe. pH probes can be prohibitively expensive, but cheaper

alternatives exist that still allow acceptable results: ‘Pocket’ pH meters are available for £30–£40, e.g. from: http://www.rapidonline.com/Test-Measurement/Voltcraft-PH-100ATC-pH-Meter-51-5153. Narrow range pH paper offers resolution of 0.2–0.4 pH.

Quickfit (or microscale) apparatus to carry out distillation and reflux. Note that the requirements for the Practical Endorsement require use of ‘laboratory apparatus’ for distillation and reflux, not specifically Quickfit. Experience of using Quickfit apparatus may be beneficial as preparation for the written assessments.

Retort stands and clamps Test tubes and boiling tubes Test-tube holders Stoppers Dropping pipettes Filter funnels, or apparatus to carry out filtration under reduced pressure: Buchner flask and Buchner funnel

or boiling tube with side-arm and Hirsch funnel Filter paper Volumetric flasks (250 cm3 or 100 cm3) Conical flasks (250 cm3, 100 cm3) Watchglasses Separating funnels Melting point apparatus or oil bath/Thiele tubes Melting point tubes (capillary tubes) Chromatography paper or thin layer chromatography plates Voltmeter (or multimeter) Apparatus for setting up electrochemical cells Wash bottles with distilled water

© OCR 2017 49 v1.0 – 10 October 2017

Apparatus potentially required

The following laboratory equipment may additionally be required to support further practical work towards the Endorsement as well as to support teaching of the specification and preparation for the written examinations.

Plastic/styrofoam cups for use as a calorimeter Pipeclay triangles Porcelain crucibles + lid Bunsen burners Glass rods Heat proof mats Tripods and gauze Colorimeter Data loggers

© OCR 2017 50 v1.0 – 10 October 2017