Acids & Bases solution with pH < 7 tastes sour react with bases turn litmus red solution with pH > 7 tastes bitter soapy texture (slippery feel) react with acids turn litmus blue Strong: - stomach acid - battery acid - strong hydrochloric acid Weak: - tomato juice - saliva - coffee Strong: - ammonia - drain cleaner - oven cleaner Weak: - baking soda - detergent - antacids

pH measure of hydrogen ions in a solution pH 7 acidicneutral basic (or alkaline) Pure Water Human Blood 4.6 – Fish Start to Die 4.0 – Most Animals Dead Lakes & Soil in Alberta ACIDICBASICNEUTRAL Stomach Acid Tomato Juice Oven Cleaner Antacids

Rain Water Milk Toothpaste Detergent/Soap Household cleaners Human Blood Carrots Wine Acid Rain Borax Sodium hydroxide (NaOH) Aspirin CORROSIVE CAUSTIC

Measuring pH pH meter - direct measure of pH litmus paper pHydrion indicator paper

universal indicators e.g. phenophthalein, bromothymol blue, methyl orange red cabbage juice indictor

Neutral Substances pH 7, neither acidic nor basic when an acid & base are mixed in correct proportions they react and form a neutral solution → this reaction is called NEUTRALIZATION –neutralization produces salt and water e.g. HCl (aq) + NaOH (aq) → NaCl (s) + H 2 O (l) hydrochloric sodium sodium water acid hydroxide chloride

Impacts to the Environment industrial activities emit gases such as CO 2 and SO 2 when these gases dissolve in water they form acids → ACID RAIN acid rain can lower the pH of water and soil… having a negative impact on the health and survival of many living organisms sometimes we treat acidic areas with lime (a base) to neutralize the acid watch acid rain lab

acid rain is the most common way we alter the pH of our environment changing pH is most noticed in water bodies… including the oceans acidification of oceans – 6 minacidification of oceans – 21 min

Potential Impacts of Changing pH in our Environment declining health/death for living things –especially respiratory illnesses for humans –especially for corals, shellfish, etc. as shells weaken/dissolve decay of materials such as metal & rock allow toxic levels of metals to become available in the environment allow transport of other pollutants more readily through the environment (e.g. pesticides) pathogens (e.g. bacteria) can become more successful