2022

• green copper carbonate and sulfuric acid used to produce blue copper sulfate crystals

  -green solid/powder

  -colourless solution

  -blue solution formed
• How can excess copper carbonate be removed?

  filtration
• This

  reaction is neutralisation
• potssium sulphate-$K_2SO_4$
• group 7 known as

  halogens
• Plan to Find Reactivity Order Using Temperature Change:

  • Use 3 polystyrene cups and measure 100 cm³ of hydrochloric acid into each (same concentration).
  • Record the starting temperature of the acid in each cup using a thermometer.
  • Add a fixed mass of metal (e.g. 3 g of each different metal) to each cup one at a time.
  • Stir gently and record the highest temperature reached during the reaction.
  • For each metal, calculate the temperature change (highest temp - starting temp).
  • Repeat the experiment for each metal to improve reliability and calculate a mean temperature change.
  • Use the average temperature changes to rank the metals by reactivity:
  • The greater the temperature rise, the more reactive the metal.
• Why does group 7 react in a similar way

  They have 7 electrons in the outer shell
• Trend in Melting Points of Group 7 Elements:

  • Group 7 molecules increase in size as you go down the group.
  • This causes intermolecular forces to become stronger.
  • So more energy is needed to overcome these forces, meaning melting points increase with increasing relative atomic mass.
• bromine is

  solid (s)
• carbon molecule

  fullerene
• Name one more process that happens at the surface of bromine at its boiling point.

  condensation
• name one property that makes the carbon molecule useful in nanotechnology

  conducts heat
• Why Other Metals Are Added to Aluminium (Alloys):

  • Other metal atoms are different sizes to aluminium atoms.
  • This distorts the layers in the structure.
  • So the layers can't slide over each other easily.
  • This makes the alloy stronger and harder than pure aluminium.


  yh
• Bonding in Polymers – Chains vs Between Chains:

  • Covalent bonds hold the atoms within each polymer chain.
  • Intermolecular forces act between the polymer chains.
  • Covalent bonds are strong, but intermolecular forces are weak.
• strong acid

  completely ionises in aq solution
• Using Magnesium to Distinguish Strong and Weak Acids:

  • Magnesium will fizz faster in the strong acid.
  • This is because strong acids release more hydrogen ions, so the reaction is quicker.


  yh
• Change in pH When Concentration Increases by Factor of 100:

  • pH decreases by 2
  • Because a factor of 100 = 10², and each pH unit = 10× change in H⁺ ions
• How Sodium Metal Conducts Electricity (2 marks)

  • Sodium has delocalised electrons.
  • These electrons carry electrical charge through the metal.
• How Sodium Chloride Can Conduct Electricity (3 marks)

  • Sodium chloride only conducts electricity when molten or dissolved (liquid).
  • This is because the ions are free to move.
  • These moving ions carry the electrical current.