1. Acid and Bases 5.3 and 5.4 -Types of Oxides- Many acids and bases are formed by dissolving oxides in water

2. At the end of this, you should able to: Classify oxides as acidic or basic based on metallic/non-metallic character Give examples of each Discuss neutralization reactions

3. What is an oxide? An oxide is a compound of oxygen and another element. Most oxides can be grouped into two types: acidic oxides (or non-metal oxide (NMO) produce an aq sol’n pH less than 7) basic oxides (or metal oxides (MO) produce an aq sol’n pH greater than 7)

4. Acidic oxides (NMO) Oxides of non-metal (NMO) Acidic oxides are often gases at room temperature.

5. Acidic oxides (NMO) React with water to produce acids. Example: sulphur trioxide + water sulphuric acid SO 3 + H 2 O H 2 SO 4

6. Acidic oxides (NMO) React with basic oxide (MO) to produce ternary salts (ionic compound, MNMO). Example: sulphur trioxide + sodium oxide sodium sulphate SO 3 + Na 2 O Na 2 SO 4

7. Acidic oxides React with bases to produce salts and water Example: carbon dioxide + sodium hydroxide sodium carbonate + water CO 2 + 2NaOH Na 2 CO 3 + H 2 O

8. Examples of acidic oxides Acidic Oxide Formula Acid Produced with Water sulphur trioxideSO 3 sulphuric acid, H 2 SO 4 sulphur dioxideSO 2 sulphurous acid, H 2 SO 3 carbon dioxideCO 2 carbonic acid, H 2 CO 3 phosphorous(V) oxide P 4 O 10 phosphoric acid, H 3 PO 4

9. Facts about Acidic Oxides When CO 2 (from combustion reactions) reacts with H 2 0 in the atmosphere, carbonic acid is formed. The acidity (low pH) produced is of concern to all aquatic animals that have shells like zooplankton, snails, crab…since it thins their shells... making them weaker, more prone to infection…all food webs are affected too. Nitrogen monoxide produced in the car engine is a respiratory irritant. It is mostly removed from the exhaust with a catalytic converter Sulphur trioxide produces sulphuric acid which comes down as acidic rain and snow and destroys aquatic and terrestrial ecosystems

10. Basic oxides (MO) Oxides of metal (MO) Basic oxides are often solids at room temperature. Most basic oxides are insoluble in water. Calcium oxide (quicklime)

11. Basic oxides (MO) React with non-metal oxides (NMO) to produce ternary salts (ionic compounds, MNMO) Example: Magnesium oxide + carbon dioxide magnesium carbonate MgO + CO 2 MgC O 3

12. Basic oxides (MO) React with acids to produce salts and water only. Example: Magnesium oxide + hydrochloric acid magnesium chloride + water MgO + 2HC l MgC l 2 + H 2 O This is a neutralisation reaction

13. Examples of basic oxides Basic Oxide Formula magnesium oxideMgO sodium oxideNa 2 O calcium oxideCaO copper(II) oxideCuO

14. Facts about basic oxides CaO is called lime. Adding CaO to acidic lakes by dropping it from a plane results in a less acidic lake or neutral lake and is called “liming” When lime is added to water, it forms a solution of calcium hydoxide(quicklime)... important in glass, paper and cement NaOH is the most widely used chemical in the world- billions of kg of sodium hydroxide is made and sold all over the world NaOH is used to make paper, detergent, aluminum…thousands of products

15. Neutralization Reactions…upset stomach…too much acid? Try a Tums (CaCO 3 ) It is a ternary salt with a polyatomic ion. It will react with HCl in the stomach and produce CaCl 2 and H 2 CO 3 which further breaks down to CO 2 and H 2 O + no more acidity, Ca +2 ions absorbed… good for bones - gas produced… Try milk of magnesia (Mg(OH) 2 ) Only slightly soluble in water so the basic characteristics not felt in the mouth and esophagus (aq.). MgCl 2 and H 2 O produced + no more acidity - difficult to swallow since slightly bitter Do not try NaOH…very soluble in water…ouch!

16. Acids and Bases in Action Acid rain causes a decrease in reproduction and a crash in populations especially aquatic ones. A lake can be treated with lime. Some lakes are affected more (N Ont., ground is granite) and others less (S Ont., ground is limestone) by acid rain. Limestone= nature’s natural antacid Leavening agents= substances that produce CO 2 gas in baking Citric acid (from fruit) reacts with baking soda (NaHCO 3 ) creating CO 2 gas, sodium citrate and water Baking powder has dry tartaric acid and baking soda. It is activated by moisture. Recycling of car battery parts requires the work of acids and bases…great example of chemistry at work

17. Both an Acid and a Base! Sodium Hydrogen Carbonate…it rhymes NaHCO 3 Can react with a strong acid to produce a salt, water and carbon dioxide thus acting as a base (proton acceptor) NaHCO 3 + HCl → H 2 CO 3 + NaCl → H 2 O + CO 2 + NaCl NaHCO 3 Can react with a strong base to form a salt and water thus acting as an acid (proton donor) NaHCO 3 + NaOH = Na 2 CO 3 + H 2 O