Chemistry Acids and Bases Unit Notes Properties of Acids & Bases Property Majority of ions present Acids pH range Indicators Taste Reactivity Electrolyte? Examples The pH Scale • The “Potential of _____________” • Used to ____________ convey the acidity of a solution Acid Base Theories Arrhenius Theory Arrhenius acids increase [___] in aqueous solution ▫ [H+] = __________ ion concentration Arrhenius bases increase [____] in solution ▫ [OH-] = __________ ion concentration ▫ ALL Arrhenius bases ______ contain hydroxide! Bases Bronsted-Lowry Theory • Bronsted-Lowry Acids ______ protons ▫ A proton is just _____! • Bronsted-Lowry Bases ________ protons • _______ Arrhenius bases are Bronsted-Lowry, but _____ _____ Bronsted-Lowry bases are Arrhenius! Ex. NaOH is a base according to Arrhenius and B-L, but NH3 is only a base according to B-L, not Arrhenius. Strength vs. Concentration • The ____________________ of an acid or base is simply its molarity ▫ • Molarity (M) = The _________________ of an acid or base is determined by the percent it ____________ in solution ▫ Weak does ________ _________ harmless!!! You can have a very weak but harmful acid. ▫ HF is ___________, but it sure looks painful! STRONG Acids and Bases Ionization Ions WEAK Acids and Bases Strong or Weak??? H2SO4 HNO3 HClO4 HClO3 HCl HBr HI Strong Acids Sulfuric acid Nitric acid Perchloric acid Chloric acid Hydrochloric acid Hydrobromic acid Hydroiodic acid Ca(OH)2 Sr(OH)2 Ba(OH)2 LiOH NaOH KOH RbOH CsOH Strong Bases Calcium hydroxide Strontium hydroxide Barium hydroxide Lithium hydroxide Sodium hydroxide Potassium hydroxide Rubidium hydroxide Cesium hydroxide Practice: 1. Arrhenius acids increase ______ ions when dissolved in water. 2. Arrhenius bases increase _____ ions when dissolved in water. 3. BrØnsted-Lowry acids ______ protons (H+) when dissolved in water. 4. BrØnsted-Lowry bases ______ protons (H+) when dissolved in water. 5. True or False: A concentrated weak acid can be just as harmful as a diluted strong acid. 6. If only 50% HF acid ionizes in water, it is a (strong/weak) acid. 7. If 100% of the base KOH ionizes in water, it is a (strong/weak) base. Check the appropriate box for each substance in the chart below: Substance HC2H3O2 (acetic) NH4OH Mg(OH)2 HCl H2O HOH Al(OH)3 HC7H5O3 (salicylic) Acid Base Naming and Formulas of Acids • Almost all acids have 1 or more ___________ listed first HCl HNO2 HNO3 Carbonic acid Hydrocyanic acid Chlorous acid Naming and Formulas of Bases Since bases are __________________ compounds, they are named in the usual way: NH4OH is _______________________________ Al(OH)3 is _______________________________ Practice!!! Name the following acids and bases: 1) NaOH ____________________________________ 2) H2SO3 ____________________________________ 3) H2S _______________________________________ 4) H3PO4 ____________________________________ 5) HCl _______________________________________ 6) HI ______________________________________ 7) Ca(OH)2 __________________________________ 8) Mg(OH)2 __________________________________ 9) H3P________________________________________ 10) HClO _____________________________________ Write the formulas of the following acids and bases: 11) hydrofluoric acid ____________________________ 12) hydroselenic acid ___________________________ 13) carbonic acid ________________________________ 14) lithium hydroxide ___________________________ 15) nitrous acid __________________________________ 17) sulfuric acid _________________________________ 19) hydrobromic acid ___________________________ 20) hydrocyanic acid ___________________________ Calculating pH Notes & Practice Calculating pH of Acids To calculate the pH of a solution you need to know the ________________ _______ concentration. o [H+] o You will either be told “the hydrogen ion concentration is…” or “the molarity (M) is…..” To find the pH, you will use the log button on your calculator. Just type it in!!! Try these 1. What is the pH of lemon juice if the hydrogen ion concentration is 0.005 M? 2. What is the pH of a 1.4 x 10-5 M HCl solution? 3. I have a mystery solution with a hydrogen ion concentration of 6.0 x 10-12 M. Find the pH of this solution, and then identify the solution as acid or base. Interpreting the relationship between ion concentration and pH: 1. pH refers to the ___________ ion concentration. 2. As the [H+] goes from 1 x 10-2 to 1 x 10-6, the pH goes from ____ to ____. 3. The concentration of the [H+] in question 2 is decreasing, making the solution less _____________. This also means the [OH-] is going ______________. 4. If the [H+] goes up, the pH will go ______________. 5. If the [OH-] goes up, the pH will go _______________. 6. If the [H+] goes down, the [OH-] must go _____________. 7. When does the [H+] = [OH-] ? ________________________. Complete the following chart over pH. Concentration pH Acid, Base, or Neutral? 0.01 M 1.0 x 10-10 M 5.0 x 10-3 M hydrogen ion = 0.030 M 1 x 10-7 M [H+] = 0.045 0.0000058 M 0.50 M hydrogen ion = 0.00138 M 4.4 x 10-5 M 1.50 x 10-11 M BOX your answers below. 1. What is the pH of a solution with a [H+] of 5.78 x 10-6 M? 2. What is the pH of a 6.8 x 10-7 M HNO3 solution? 3. Calculate the pH of a solution with a hydrogen ion concentration of 2.1 x 10-4 M. 4. What is the pH of a solution with a hydrogen ion concentration of 3.11 x 10-9 M. 5. What is the pH of a 4.08 x 10-7 M solution? Neutralization Reactions Neutralization Reactions When acids and bases are mixed together, their pH becomes more ______________. Therefore, we call these neutralization reactions. The products of a neutralization reaction are always _________________ and a ______________. o A “salt” can be any ________________ compound that dissociates in water. Acid + Base Water + Salt Neutralization is a ________________________ _________________________ reaction. The _________ from the acid bonds with the ___________ from the base, to form WATER. The _____________ from the acid and the _____________ from the base bond to form the SALT. _____HF + _____NaOH _____H2CO3 + _____Sr(OH)2 _____Ca(OH)2 + _____Zn(OH)2 + _____H3PO4 _____HNO3 Complete the neutralization reactions below. 1. _____HCl + 2. _____CsOH 3. _____HF 4. _____HCl _____NaOH + + + _____H2CO3 _____Mg(OH)2 _____Al(OH)3