Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
3.3(a) Redox Learning Outcomes In all cases pupils should be able to state that: The electrochemical series 1 Electricity can be produced by connecting different metals together, with an electrolyte, to form a simple cell. 2 The voltage between different pairs of metals varies and this leads to the electrochemical series. 3 Electricity can be produced in a cell by connecting two different metals in solutions of their metal ions. 4 Electricity can be produced in a cell when at least one of the half-cells does not involve metal atoms. 5 Electrons flow in the external circuit from the species higher in the electrochemical series to the one lower in the electrochemical series. 6 The purpose of the ‘ion bridge’ (salt bridge) is to allow the movement of ions to complete the circuit. Redox reactions 7 Oxidation is the loss of electrons by any reactant in a chemical reaction. 8 A metal element reacting to form a compound is an example of oxidation. 9 Reduction is a gain of electrons by a reactant in any reaction. 10 A compound reacting to form a metal is an example of reduction. 11 In a redox reaction, oxidation and reduction occur together. 12 Ion-electron equations can be written for oxidation and reduction reactions. 13 Ion-electron equations can be combined to produce redox equations. 14 Chemical cells are examples of redox reactions 15 A simple cell can be set up to investigate which factors might affect the size of the voltage produced by the cell. 16 One factor that can be investigated is to find out if different pairs of metals produce different voltages. 17 Another factor could be to investigate whether the electrolyte affects the size of the voltage produced. Displacement 18 Displacement reactions occur when a metal is added to a solution containing ions of a metal lower in the electrochemical series. 19 Displacement is another example of a redox reaction. 20 The reaction of metals with acids can establish the position of hydrogen in the electrochemical series. Electrolysis 21 Electrolysis is when electricity is passed through a solution to break it up into elements. 22 Electrolysis is another example of a redox reaction. 23 During electrolysis, oxidation occurs at the positive electrode and reduction occurs at the negative electrode.