3.2a A physical change results in the rearrangement of existing particles in a substance. A
chemical change results in the formation of different substances with changed properties.
3.2b Types of chemical reactions include synthesis, decomposition, single replacement,
and double replacement.
3.2c Types of organic reactions include addition, substitution, polymerization, esterification,
fermentation, saponification, and combustion.
3.2d An oxidation-reduction (redox) reaction involves the transfer of electrons (e - ).
3.2e Reduction is the gain of electrons.
3.2f A half-reaction can be written to represent reduction.
3.2g Oxidation is the loss of electrons.
3.2h A half-reaction can be written to represent oxidation.
3.2i Oxidation numbers (states) can be assigned to atoms and ions. Changes in
oxidation numbers indicate that oxidation and reduction have occurred.
3.2j An electrochemical cell can be either voltaic or electrolytic. In an electrochemical
cell, oxidation occurs at the anode and reduction at the cathode.
3.2k A voltaic cell spontaneously converts chemical energy to electrical energy.
3.2l An electrolytic cell requires electrical energy to produce a chemical change. This
process is known as electrolysis.