Spec chem

• This is the GCSE Chemistry (8462) specification for teaching from September 2016 onwards, for exams in 2018 onwards, version 1.1 04 October 2019
• Contents


  • 1 Introduction
  • 2 Specification at a glance
  • 3 Working scientifically
  • 4 Subject content
  • 5 Scheme of assessment
  • 6 General administration
  • 7 Mathematical requirements
  • 8 Practical assessment
  • 9 Appendix A: periodic table
• Why choose AQA for GCSE Chemistry


  • Clear straightforward specification and exams
  • Specification developed with teachers
  • Practicals trialled by teachers
  • Straightforward exams so students can give straightforward answers
  • AQA is an educational charity focused on the needs of teachers and students
• Support and resources to help you teach

  • Teaching resources
  • Preparing for exams
  • Analyse your students' results with Enhanced Results Analysis (ERA)
  • Professional development
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• Subject content


  • Atomic structure and the periodic table
  • Bonding, structure, and the properties of matter
  • Quantitative chemistry
  • Chemical changes
  • Energy changes
  • The rate and extent of chemical change
  • Organic chemistry
  • Chemical analysis
  • Chemistry of the atmosphere
  • 10. Using resources
  • 11. Key ideas
• Assessments


  • Paper 1: Topics 1-5
  • Paper 2: Topics 6-10
• Working scientifically


  • Understand how scientific methods and theories develop over time
  • Use a variety of models to solve problems, make predictions and develop scientific explanations
  • Appreciate the power and limitations of science and consider ethical issues
  • Explain everyday and technological applications of science
  • Evaluate risks in practical science and the wider societal context
  • Recognise the importance of peer review and communicating results
  • Use scientific theories to develop hypotheses
  • Plan experiments and devise procedures
  • Apply knowledge of techniques, instruments, apparatus and materials
  • Carry out experiments appropriately
  • Recognise when to apply sampling techniques
  • Make and record observations and measurements
  • Evaluate methods and suggest improvements
• Carry out experiments appropriately

  1. Having due regard for the correct manipulation of apparatus

  2. Ensuring the accuracy of measurements

  3. Considering health and safety
• Presenting observations and other data using appropriate methods

  1. Construct and interpret frequency tables and diagrams, bar charts and histograms

  2. Plot two variables from experimental or other data
• Translating data from one form to another


  Translate data between graphical and numeric form
• Carrying out and represent mathematical and statistical analysis

  1. Use an appropriate number of significant figures

  2. Find the arithmetic mean and range of a set of data

  3. Construct and interpret frequency tables and diagrams, bar charts and histograms

  4. Make order of magnitude calculations

  5. Change the subject of an equation

  6. Substitute numerical values into algebraic equations using appropriate units for physical quantities

  7. Determine the slope and intercept of a linear graph

  8. Draw and use the slope of a tangent to a curve as a measure of rate of change

  9. Understand the physical significance of area between a curve and the x-axis and measure it by counting squares as appropriate
• Representing distributions of results and make estimations of uncertainty

  1. Apply the idea that whenever a measurement is made, there is always some uncertainty about the result obtained

  2. Use the range of a set of measurements about the mean as a measure of uncertainty
• Interpreting observations and other data (presented in verbal, diagrammatic, graphical, symbolic or numerical form), including identifying patterns and trends, making inferences and drawing conclusions

  1. Use data to make predictions

  2. Recognise or describe patterns and trends in data presented in a variety of tabular, graphical and other forms

  3. Draw conclusions from given observations
• Presenting reasoned explanations including relating data to hypotheses

  1. Comment on the extent to which data is consistent with a given hypothesis

  2. Identify which of two or more hypotheses provides a better explanation of data in a given context
• Being objective, evaluating data in terms of accuracy, precision, repeatability and reproducibility and identifying potential sources of random and systematic error

  1. An accurate measurement is one that is close to the true value

  2. Measurements are precise if they cluster closely

  3. Measurements are repeatable when repetition, under the same conditions by the same investigator, gives similar results

  4. Measurements are reproducible if similar results are obtained by different investigators with different equipment

  5. Measurements are affected by random error due to results varying in unpredictable ways; these errors can be reduced by making more measurements and reporting a mean value

  6. Systematic error is due to measurement results differing from the true value by a consistent amount each time

  7. Any anomalous values should be examined to try to identify the cause and, if a product of a poor measurement, ignored
• Use scientific vocabulary, terminology and definitions
• Recognise the importance of scientific quantities and understand how they are determined
• Use SI units (eg kg, g, mg; km, m, mm; kJ, J) and IUPAC chemical nomenclature unless inappropriate
• Use prefixes and powers of ten for orders of magnitude (eg tera, giga, mega, kilo, centi, milli, micro and nano)
• Interconvert units
• Use an appropriate number of significant figures in calculation
• Relative atomic mass


  An average value that takes account of the abundance of the isotopes of the element
• Calculating relative atomic mass

  Given the percentage abundance of isotopes
• Electronic structure


  The electrons in an atom occupy the lowest available energy levels (innermost available shells)
• Representing electronic structure


  • 2,8,1 for sodium
  • Diagram showing two electrons in the lowest energy level, eight in the second energy level and one in the third energy level
• Periodic table


  • Elements are arranged in order of atomic (proton) number
  • Elements with similar properties are in columns, known as groups
  • The table is called a periodic table because similar properties occur at regular intervals
• Relationship between position in periodic table and electron arrangement

  Elements in the same group have the same number of electrons in their outer shell (outer electrons) and this gives them similar chemical properties
• Predicting reactions and reactivity from position in periodic table

  Possible reactions and probable reactivity can be predicted
• Development of periodic table

  • Before discovery of protons, neutrons and electrons, scientists arranged elements by atomic weights
  • Early periodic tables were incomplete and some elements were placed in inappropriate groups
  • Mendeleev left gaps for undiscovered elements and changed order based on atomic weights
  • Discovery of isotopes explained why order based on atomic weights was not always correct
• Metals


  Elements that react to form positive ions
• Non-metals


  Elements that do not form positive ions
• Position in periodic table

  • Metals are found to the left and towards the bottom
  • Non-metals are found towards the right and top
• Group 0 (noble gases)

  • Unreactive and do not easily form molecules
  • Atoms have stable arrangements of electrons
  • Boiling points increase with increasing relative atomic mass
• Group 1 (alkali metals)


  • Characteristic properties due to single electron in outer shell
  • Reactivity increases going down the group
• Group 7 (halogens)


  • Similar reactions due to seven electrons in outer shell
  • Further down the group, higher relative molecular mass, melting point and boiling point
  • Reactivity decreases going down the group
  • More reactive halogen can displace less reactive halogen from aqueous solution
• Transition metals


  • Different properties compared to Group 1 elements, e.g. higher melting points, densities, strength, hardness, lower reactivity
• Typical transition metal properties

  • Ions with different charges, form coloured compounds, useful as catalysts
• Chemical bonds


  • Ionic - formed from oppositely charged ions
  • Covalent - formed by sharing pairs of electrons
  • Metallic - formed by sharing delocalised electrons
• Ionic bonding


  • Occurs in compounds formed from metals combined with non-metals
  • Involves transfer of electrons from metal to non-metal
• Representing ionic bonding


  Using dot and cross diagrams