7.S.II.7

Kinds of reactions Oxidation: a chemical reaction that commonly involves oxygen. More generally, oxidation is a reaction in which an atom accepts electrons while combining with other elements. The atom that gives away electrons is said to be oxidized. Examples: rusting of iron, burning of paper. Heat is given off. Reduction: the opposite of oxidation. Reduction involves the gaining of electrons. An oxidized material gives them away and heat is taken up. Acids: for example, vinegar, HCl, H2SO4; sour; turn litmus red Bases: for example, baking soda; bitter; turn litmus blue pH: ranges from 0-14; neutral = 7, acid = below 7, base = above 7 Reactions with acids and bases In water solution, an acid compound has an H ion (a proton lacking an electron), and the base compound has an OH ion (with an extra electron). When the two come together, they form HOH (water) plus a stable compound called a “salt.