Science 10 - Chemistry 5.2 - Salts

Acid-Base Neutralization Salts are a class of ionic compounds that can be formed during the neutralization reaction of an acid and a base. They are composed of a positive ion (cation) and a negative ion (anion) Neutralization reactions occur when an acid and a base react to produce a salt and water. HCl(aq) + NaOH(aq)  NaCl(s) + H2O(l ) acid base salt water Do practice problems on page 236 Do practice problems on page 236

Metal Oxides and Non-Metal Oxides Metal oxides react with water to form bases. Ex. Na2O(s) + H2O(l )  2NaOH(aq) Non-metal oxides react with water to form acids Ex. SO2(g) + H2O(l )  H2SO3(aq) Non-metal oxides are formed from the burning of fossil fuels Add water in the atmosphere = acid precipitation

Acids and Metals Acids and Metals The most reactive metals, at the bottom of groups 1 and 2, react vigorously with water and acids. All other metals are less reactive than those in groups 1 and 2. When metals do react with acids, H2 gas is usually released and a salt is produced. Ex: 2HCl(aq) + Mg(s)  MgCl2(s) + H2(g) acid metal salt hydrogen gas Do practice problems on page 238

Acids and Carbonates Acids and Carbonates Carbonates (-CO3) neutralize acids, protecting locations with natural carbonate supplies from acid precipitation. H2SO4 + CaCO3 CaSO4 + H2O + CO2 sulphuric calcium calcium water carbon acid carbonate sulphate dioxide

Adding lime (calcium carbonate CaCO3) to a lake is called “liming.” When and why would this be helpful? Why is it not practical to always do liming? What is a better alternative?