Paper 1 Model Answers

• three observations when an excess of copper carbonate reacts with sulfuric acid: 1. colourless solution 2. fizzing 3. copper carbonate left at the end
• to remove the excess of copper carbonate from sulfuric acid, use filtration
• the pH of copper sulphate at the end of the experiment is 7
• copper carbonate and sulfuric acid react to produce copper sulfate, this is a neutralisation or exothermic reaction
• the formula of potassium sulphate is K2 SO4
• group 7 elements are known as the halogens
• group 7 elements react in similar ways because they all have 7 electrons in their outer most shell
• the melting points of group 7 elements increase going down the group because molecules increase in size going down the group so the forces between the molecules increase
• the state symbol for bromine at -50C is solid
• at the surface of bromine at its boiling point, evaporation, condensation and boiling occur
• fullerene conducts heat, which makes it very useful in nanotechnology
• aluminium is an alloy because other metal atoms have different sizes to aluminium atoms so the layers of aluminium atoms are distorted so the layers can't slide which makes the alloy harder
• hydrochloric acid is a strong acid, which is an acid that completely ionises in aqueous solutions
• magnesium can be used to distinguish between a strong and weak acid of the same concentration because magnesium disappears at a greater rate with a strong acid
• if the concentration of HCI is increase by a factor of 100, this makes the pH decrease by a unit of 2
• a half equation to show that sodium is oxidised when eating with titanium chloride (which is a redox reaction): Na -> NA+ + e-
• sodium conducts electricity because it has delocalised electrons that carry the charge through the metal
• sodium chloride can conduct electricity when liquid or molten because the ions are free to move