How to Balance Redox Equations in Alkaline (and Acid) Solutions?
The Fuel Cell of Hydrogen and Oxygen can take place in Acid or Alkaline Solution. H₂ + 2 O₂ ------> 2 H₂O In either situation we first balance the redox equations in acid solution Oxidation Half Equation H₂ -----> H₂O 1. Add H₂O to balance O H₂O + H₂ -----> H₂O 2. Balance H with H+ H₂O + H₂ -----> H₂O + 2H⁺ 3. Balance charge with e⁻ There is 0 on LHS and +2 on RHS so add 2e to the RHS H₂O + H₂ ----> H₂O + 2H⁺ + 2e⁻ Cancel H₂O The oxidation equation is balanced in acid solu
Born Haber Cycle Screenshot - Student completes Born Haber cycle for Aluminium Oxide..
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Enthalpy of Solution Screenshot
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How to Balance Redox Equations
Sulphuric Acid is reduced by Iodide ions to form Sulphur Dioxide and Iodine. Reduction Half Equation H₂SO₄ -----> SO₂ 1. Balance the species that has been oxidised or reduced. In this case the sulphur has been reduced from +6 to +4. The sulphur atoms are balanced. 2. Balance oxygen using H₂O There are 4 on LHS and 2 on RHS so add 2 H20 to the RHS H₂SO₄ ----> SO₂ + 2H₂O 3. Balance hydrogen atoms (H+) There are 2 on LHS and 4 on RHS so add 2H+ to LHS H₂SO₄ + 2H⁺ ----> S
Limiting Reagents
If you have worked out the MOLES of two reactants then the limiting reagent is the one with less moles. Sorted? Well, it depends. If the reactants are in a 1:1 ratio then the above is true. But if the ratio is not equal then I'm afraid it's a bit more complicated. Let's say reactants A and B have a ratio of 2:1 in the balanced equation. If we have 0.020 moles of A and 0.015 moles of B which is the limiting reagent? If we start with A we can see from the ratio that 0.02 moles
