Do you struggle with the difference between Lavoisier, Arrhenius and Davy or do chemical calculations always leave you stumped? Each week our tutors will address the main issues and calculations within each of the modules of the year 12 chemistry syllabus and also give advice on how to answer some of the extended response questions.

9.2 Production of Materials

Important issues which students normally forget to address:

• The systematic name of polystyrene;
• The structure of cellulose;
• Why a catalyst is needed for the addition of water to ethylene in order to form ethanol;
• The reasons underlying the multiple uses of ethanol as a solvent;
• The use and development of biopolymers – remember that the syllabus asks you to analyse the progress of the biopolymer;
• The proper construction of a galvanic cell – remember you need to label the cathode and anode (and what metal they are composed of), the solution used for the saltbridge and what the electrodes are sitting in, and the direction of the electron flow;
• How commercial radioisotopes and transuranic elements are produced;
• Recent discoveries of elements.

Calculations

• Molar Heat of Combustion – Process

• 1. Use q=-mcΔt….where m is the mass of the water, c is the specific heat capacity of water (-4.18Jk^-1g^-1) and Δt is the change in temperature.
  2. Convert the value calculated into kJ by just dividing it by 1000.
  3. Find out the number of moles of the fuel used in the experiment.
  4. Divide the value (the one calculated in point 2) by the number of moles of the fuel.
  5. Remember to include the SI units in your final answer, i.e -1020kJ mol^-1 and also that the answer is negative as the process is exothermic.

Past Questions

Our tutors will make any corrections and provide a proper approach to the questions.

• Explain why ethanol can dissolve a whole range of small substances such as salts, polar molecules and even non-polar molecules to a small extent.

• Analyse progress in the development and use of a named biopolymer. This analysis should name the specific enzyme(s) used or organism used to synthesise the material and an evaluation of the use or potential use of the polymer produced related to its properties.