2 Properties of Acids What is an Acid? An acid is any substance that creates Hydrogen Ions (H+) in water.Acids share several characteristics…Acids taste sourAcids react with metalsAcids react with carbonatesAcids turn blue litmus red
3 Properties of Acids Sour Taste Items such as citrus fruits are acidic in natureThey contain citric acid which gives them their sour taste
4 Properties of Acids Acids react with metals Acids will “eat away” at metals such as magnesium zinc, and iron.This property is described as being corrosiveAcids react with carbonatesCarbonate ions (CO32-) have a negative charge and when acids react with them Carbon Dioxide gas is producedAn example would be the reaction of Hydrochloric Acid (HCl) with Limestone
5 Uses of Acids Acids are used in a variety of ways every day: Many of the foods we eat contain acidsAcids are often used in cleaning suppliesAcids in your stomach allow you to digest foodLactic acid in your muscles causes fatigueAcids are used in lawn care products
6 Examples of Acids Hydrochloric Acid – HCl Nitric Acid – HNO3 Sulfuric Acid – H2SO4What do you notice about the first letter of each?What does this tell you about the molecule?
7 Properties of Bases What is a base? A base is any substance that produces Hydroxide Ions ( OH-) in waterBases share several characteristics:Bases have a bitter tasteBases feel slipperyBases turn red litmus blueBases do not react with metals or carbonates
8 Properties of Bases Bases have a bitter taste Tonic water is a drink that has a bitter taste due to the base quinine.
9 Properties of Bases Bases have a slippery feel Items such as soap and shampoo are bases
10 Uses of Bases Bases are also useful to us everyday: Baking soda reacts with acids in baking to create the carbon dioxide gas that causes bread to riseMilk of Magnesia and Calcium Carbonate are used to neutralize stomach acidsMany cleaning supplies have bases in themBases are used to help make mortar and cement
11 Examples of Bases Sodium Hydroxide – NaOH Potassium Hydroxide – KOH Calcium Hydroxide – Ca(OH)2Magnesium Hydroxide -- Mg(OH)2What do you notice about the ending of each base?What does this tell you about each molecule?
12 Measuring the Strength of Acids and Bases To measure the strength of Acids and Bases we use the pH scale which ranges from 0 – 14.The pH scale measure the concentration of Hydrogen Ions in a solutionWhen pH is low, the concentration of hydrogen ions is high.The lower the pH the stronger the AcidThe higher the pH the stronger the baseA pH of 7 is considered neutral
14 What happens when Acids and bases React with each other? The reaction between an acid and a base is called a neutralization reactionThe products of these reactions are a salt and waterA salt is any ionic compound formed by a neutralization reactionWater comes from the combination of the hydrogen ions and the hydroxide ionsAlthough it is called a neutralization reaction, the resulting solution is not always neutral (pH of 7). It depends on the strength of the acid and the base that are combined.