3.2.13 standard electrode potentials

(HL)#chem whatarethemechanismsofchemicalchange

Reactivity 3.2.13 - standard cell potential, can be calculated from standard electrode potentials. has a positive value for a spontaneous reaction

• the electromotive force can be calculated for a voltaic cell made from any two half-cells and deduce the direction of electron flow
• cell potential is the difference in the tendencies of the half-cells to be reduced

the values used must be the reduction potentials in the data tables

determining the direction of reaction spontaneity

electrons move from the half-cell with the more negative electrode potential to the half-cell with the less negative electrode potential

• if is positive, the reaction is spontaneous
• if is negative, the reaction is non-spontaneous and the reverse reaction is spontaneous

comparing relative oxidising and reducing power of half-cells

the more negative , the stronger the reducing agent

• wants to get rid of electrons
  the more positive , the stronger the oxidising agent
• wants to gain electrons