Unit 6: Acid-Base Applications Lesson 8: Oxides in Water

Metal Oxides in Water Metal oxides are a type of salt and thus dissociate completely in water: e.g. Na2O(s) → 2 Na+ + O2- The metal ions that form are always spectators, but O2- is a strong base: O2- + H2O → 2 OH- Putting these together, the overall reaction is: Na2O + H2O → 2 NaOH

Non-Metal Oxides in Water When a non-metal oxide reacts with water, the water bonds to the molecule to produce an acid. For example: CO2 + H2O → H2CO3 SO2 + H2O → H2SO3 SO3 + H2O → H2SO4

Practice: Pg. 185 #144-145 10 min

Brain Break! Climb the ladders by changing one letter at a time to get from one word to the other. e.g. Sun, fun, fur, for, fog

Acid Rain Because of dissolved CO2, rain is naturally slightly acidic, with a pH of about 5.6. Rain with pH < 5.0 is considered “acid rain.”

What Causes Acid Rain? The main contributors to acid rain are SOx and NOx. SOx is the mixture of SO2 and SO3, which come from the burning of coal, oil, and most other fuels. NOx is the mixture of NO and NO2, which come from combustion reactions (such as those that occur in automobile engines).

Why Should We Care? Acidified water and soil kills fish and plants. Acid rain leaches poisonous substances out of rocks and removes nutrients from topsoil. Metal and stone structures are slowly destroyed by acid rain.