feasibility of a reaction Determine the temperature at which by the relationship: Deduce how varies with a reaction becomes feasible. ΔG = TΔS temperature. ΔG ΔH – Use graphs to deduce how ΔG For a reaction to be Determine the temperature varies with temperature. feasible, the value of at a reaction becomes must be zero or feasible. Practical activities: ΔG negative. Find vaporisation of water. ΔS Carry out test-tube reactions to deduce the signs of and ΔH, ΔS ΔG for different reactions and check observations by calculating values. 3.1.11 2.0 Use IUPAC cell notation to Students draw electrochemical cells January 2013 Knockhardy electrochemistry Electrode potentials weeks represent cells. for different combinations of half Unit 5 Q7 powerpoint: cells, and use EƟ values to 3.1.11.1 Understand that potentials calculate EMFs. January 2012 Electrode potentials and are measured relative to Unit 5 Q4 cells the standard hydrogen Students use the electrochemical electrode. series to predict and explain the June 2006 Understand that a direction of reactions. Unit 5 Q4 potential difference is The potential of an set up between two half electrode is affected by Students use Le Chatelier’s January 2004 cells (electrodes) that conditions. Principle to predict how changing Unit 5 Q4 are joined by a salt concentration affects electrode bridge. Know the standard potential values, and plan an June 2011 conditions under which experiment to test predictions. Unit 5 Q5 Understand that potentials are measured. electrode potentials are Practical activities: measured relative to the
feasibility of a reaction by the relationship: ΔG = ΔH – TΔS For a reaction to be feasible, the value of ΔG must be zero or negative. Deduce how ΔG varies with temperature. Determine the temperature at a reaction becomes feasible. Determine the temperature at which a reaction becomes feasible. Use graphs to deduce how ΔG varies with temperature. Practical activities: Find ΔS vaporisation of water. Carry out test-tube reactions to deduce the signs of ΔH, ΔS and ΔG for different reactions and check observations by calculating values. 3.1.11 Electrode potentials 3.1.11.1 Electrode potentials and cells Understand that a potential difference is set up between two half cells (electrodes) that are joined by a salt bridge. Understand that electrode potentials are measured relative to the 2.0 weeks Use IUPAC cell notation to represent cells. Understand that potentials are measured relative to the standard hydrogen electrode. The potential of an electrode is affected by conditions. Know the standard conditions under which potentials are measured. Students draw electrochemical cells for different combinations of half cells, and use EƟ values to calculate EMFs. Students use the electrochemical series to predict and explain the direction of reactions. Students use Le Chatelier’s Principle to predict how changing concentration affects electrode potential values, and plan an experiment to test predictions. Practical activities: January 2013 Unit 5 Q7 January 2012 Unit 5 Q4 June 2006 Unit 5 Q4 January 2004 Unit 5 Q4 June 2011 Unit 5 Q5 Knockhardy electrochemistry powerpoint:
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