Chemical changes Study Guide

A base is a chemical substance characterised by its ability to react with an acid. This reaction, known as a neutralisation reaction, consistently yields two specific products: a salt and water. This definition is fundamental in general chemistry and helps classify various compounds, differentiating bases from other types of substances like alkalis, which are soluble bases. Common examples of bases include metal oxides and metal hydroxides.

Electrolysis is a chemical process that uses electrical energy to drive non-spontaneous chemical reactions. It specifically involves the decomposition of an electrolyte—a substance that contains free ions and is capable of conducting electricity—by passing a direct electrical current through it. In this process, ions in the electrolyte move towards electrodes of opposite charge. Positively charged ions (cations) migrate to the negatively charged electrode (cathode) and gain electrons, undergoing reduction. Negatively charged ions (anions) migrate to the positively charged electrode (anode) and lose electrons, undergoing oxidation. This transfer of electrons at the electrodes causes the chemical bonds within the electrolyte to break, leading to the formation of new substances. The electrical energy supplied via the direct current effectively provides the activation energy necessary for these reactions to occur, transforming electrical energy into chemical energy.