2 D12Explain the chemical composition of acids and bases, and explain the change of pH in neutralization reactions.
3 Learning TargetI can differentiate between acids and bases.
4 Acids When dissolved in water, they ionize (form ions) Form H+ (Hydrogen) ions, which attach to water molecules to form hydronium ions, H3O+Properties:Taste sourBlue litmus paper turns redConduct electric currentCorrosive
6 Strong Acids HNO3 + H2O H3O+ + NO3- Complete ionization in water High concentration of hydronium ions in the liquidStrong acidConducts electricityStrong electrolyteElectrolyte: substance that conducts electricity when dissolved in water
7 Weak Acids CH3COOH + H2O H3O+ + CH3COO- Weak acids Low concentration of hydronium ions in the liquidDo not conduct electricity wellWeak electrolyteDouble headed arrowFew ions in a solution of acetic acid
8 Acid Safety Corrosive Can damage living tissues Vapors can be harmful to eyes, mouth and lungsWear safety goggles, gloves, lab apron
9 Bases When dissolved in water form OH- (hydroxide ions) Properties Tastes bitterSolution feels slipperyTurn red litmus paper blueLike acids, bases can also damage the skin
11 Bases When bases dissolve in water, they ionize. NaOH Na+ + OH- Not all bases contain OH-Some will react with water to form hydroxide ionNH H2O NH OH-
12 Strong Bases High concentration of OH- in the solution Ba(OH) Ba OH-Complete ionization in waterGood conductor of electricityStrong electrolyte
13 Weak Bases Low concentration of OH- in solution NH3 + H2O NH4+ + OH- Do not ionize completelyNot a good conductor of electricityWeak electrolyte
14 Base Safety Bases are corrosive and can damage living tissue Wear safety goggles, gloves and a lab apron!!
15 Let’s Review What ions do acids produce? What ions do bases produce? What is the difference between a strong acid and a weak acid?Why should we observe lab safety rules when working with acids and bases?
17 Detecting Acids and Bases You can determine if a substance is an acid or a base by using an indicator.An indicator is a substance that changes color in the presence of an acid or base.Indicators measure the level of hydronium ions. The level determines if a substance is acidic or basic.
18 Indicators Cabbage juice can be used as an indicator Litmus paper is a common indicatorAcids turn blue litmus paper redBases turn red litmus paper blueOnly indicates if a substance is an acid or a baseTo determine strength or weakness, pH values are usedcatalog.flatworldknowledge.comprofmarsolais.com
19 pH A measure of the concentration of H3O+ ions in solution Acidity or basicity of a solution can be criticalEnzymes in your body will not function properly if your blood is too basic or acidicFish cannot survive in waters that are too acidic or basicck12.orghapnotes.wikidot.com
20 Acid: substance that produces H+ ions in aqueous solution Base: substance that produces OH- ions in aqueous solutionNeutral Pure H2OIon ConcentrationIon Concentration[OH-][H+]StrongerWeakerWeakerStrongerBasesAcidspH Scale
21 pH Small differences in pH mean large differences in acidity Example: pH of coke = 3pH of coffee = 5Coke is 102 , or 100, times more acidic than coffee.ch302.cm.utexas.edu
23 Let’s ReviewLemon juice has a pH of 2.2. Is it an acid or a base?
24 Detergents such as Tide have a pH of about 10 Detergents such as Tide have a pH of about 10. Is Tide an acid or a base?
25 Seawater has a pH of 8.2. Is seawater an acid or a base?
26 The inside of your mouth has a pH of 7. Is it an acid or a base?
27 409 cleaner contains ammonia that has a pH of 12 409 cleaner contains ammonia that has a pH of 12. What will 409 do to red litmus paper?
28 A soft drink has a pH of 3.2. What will it do to a piece of red litmus paper?
29 Determining pHYou can find pH from the concentration of a strong acid.pH is the negative power of 10 that is used to describe the concentration of H3O+ ions.The concentration of H3O+ in pure water is 1 x 10-7.The pH of pure water = 7
30 Determining pHThe concentration of H3O+ ions in a solution of a strong acid is the same as the concentration of the acid.Determine the pH of a M (Molar) solution of the strong acid HCl.concentration of H3O+ ions = concentration of HClconcentration of H3O+ ions = M = 1 x 10-4 MpH = -(-4) = 4