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Working Scientifically - A-Levels Chemistry

Appendix 5a: Practical skills identified for indirect assessment and developed through teaching and learning

Question papers will assess the following abilities:

a) Independent thinking

  • solve problems set in practical contexts
  • apply scientific knowledge to practical contexts

b) Use and application of scientific methods and practices

  • comment on experimental design and evaluate scientific methods
  • present data in appropriate ways
  • evaluate results and draw conclusions with reference to measurement uncertainties and errors
  • identify variables including those that must be controlled

c) Numeracy and the application of mathematical concepts in a practical context

  • plot and interpret graphs
  • process and analyse data using appropriate mathematical skills as exemplified in the mathematical appendix for each science
  • consider margins of error, accuracy and precision of data

d) Instruments and equipment

  • know and understand how to use a wide range of experimental and practical instruments, equipment and techniques appropriate to the knowledge and understanding included in the specification

Appendix 5b: Practical skills identified for direct assessment and developed through teaching and learning

Practical work carried out throughout the course will enable students to develop the following skills.

a) Independent thinking

  • apply investigative approaches and methods to practical work

b) Use and apply scientific methods and practices

  • safely and correctly use a range of practical equipment and materials
  • follow written instructions
  • make and record observations
  • keep appropriate records of experimental activities
  • present information and data in a scientific way
  • use appropriate software and tools to process data, carry out research and report findings

c) Research and referencing

  • use online and offline research skills including websites, textbooks and other printed scientific sources of information
  • correctly cite sources of information

d) Instruments and equipment

  • use a wide range of experimental and practical instruments, equipment and techniques appropriate to the knowledge and understanding included in the specification

Appendix 5c: Use of apparatus and techniques

Use of apparatus and techniques – chemistry

Specifications for chemistry must give students opportunities to use relevant apparatus to develop and demonstrate these techniques.

All of the techniques listed below will be assessed through a minimum of 12 identified practical activities within each specification. These 'core' practicals must allow students to demonstrate all of the practical skills given in 5b.

Practical techniques to be gained by candidates

Practical technique
1.use appropriate apparatus to record a range of measurements (to include mass, time, volume of liquids and gases, temperature)
2.use water bath or electric heater or sand bath for heating
3.measure pH using pH charts, or pH meter, or pH probe on a data logger
4.use laboratory apparatus for a variety of experimental techniques, including:
• titration, using burette and pipette
• distillation and heating under reflux, including setting up glassware using retort stand and clamps
• qualitative tests for ions and organic functional groups
• filtration, including use of fluted filter paper, or filtration under reduced pressure
5.use volumetric flask, including accurate technique for making up a standard solution
6.use acid-base indicators in titrations of weak/strong acids with weak/strong alkalis
7.purify:
• a solid product by recrystallization
• a liquid product, including use of separating funnel
8.use melting point apparatus
9.use thin-layer or paper chromatography
10.set up electrochemical cells and measuring voltages
11.safely and carefully handle solids and liquids, including corrosive, irritant, flammable and toxic substances
12.measure rates of reaction by at least two different methods, for example:
• an initial rate method such as a clock reaction
• a continuous monitoring method

Appendix 5d: Mapping between Appendix 5c and core practicals (chemistry)

This qualification gives students opportunities to use relevant apparatus to develop practical skills and demonstrate competency in a range of practical techniques.

All of the techniques listed in Appendix 5c will be assessed through a series of core practical activities within this specification.

To achieve the Science Practical Endorsement, students need to show competence in the 12 practical techniques listed in Appendix 5c: Use of apparatus and techniques.

The following table shows how each core practical activity, listed in the content, maps to the required practical techniques in Appendix 5c: Use of apparatus and techniques.

Core practical mapping

Chemistry Core Practical123456789101112
1: Measuring the molar volume of a gas✓✓✓
2: Preparation of a standard solution from a solid acid✓✓✓✓✓
3: Finding the concentration of a solution of hydrochloric acid✓✓✓✓✓
4: Investigation of the rates of hydrolysis of halogenoalkanes✓✓✓✓
5: The oxidation of ethanol✓✓✓✓
6: Chlorination of 2-methylpropan-2-ol with concentrated hydrochloric acid✓✓✓✓✓✓
7: Analysis of some inorganic and organic unknowns✓✓✓
8: To determine the enthalpy change of a reaction using Hess's Law✓✓✓
9. Finding the Ka value for a weak acid✓✓✓
10. Investigating some electrochemical cells✓✓✓
11. Redox titration✓✓✓✓
12. The preparation of a transition metal complex✓✓✓✓✓
13a and 13b: Following the rate of the iodine-propanone reaction by a titrimetric method and investigating a 'clock reaction' (Harcourt-Esson, iodine clock)✓✓✓✓✓
14. Finding the activation energy of a reaction✓✓✓
15. Analysis of some inorganic and organic unknowns✓✓✓✓
16. The preparation of aspirin✓✓✓✓✓✓✓