Acids, Bases & Salts Pre-AP Chemistry LFHS

Acid Definitions: Arrhenius Acid- Any substance which releases H+ (hydrogen ions or protons) in water. Rxn: HX + H2O  H3O+ + X- (acid) (water) (hydronium ion) (conjugate base) Bronsted(Lowry) Acid- A proton(H+) donor. Rxn: HX  H+ + X- (acid) (Proton) (conjugate base)

Write the dissociation reaction for each acid: Arrhenius Bronsted HCl HCl HNO3 HNO3 HClO4 HClO4 H2CO3 H2CO3 HC2H3O2 HC2H3O2 H3PO4 H3PO4

Properties of Acids Acids: 1) Sour Taste 2) Turn litmus RED 3) Electrolytes-Acids release ions in water 4) Corrosive-cause chemical burns 5) Can react with metals to produce H2 gas 6) Acids + Bases  Salts + H2O (Neutralization Rxn) (ionic compounds)

Strong Acids- 100% dissociation in H20 Weak Acids- less than 5% dissociation in H2O Dissociation Rxn: HX  H+ + X- There are only 6 strong acids, all others are weak: HCl hydrochloric acid (stomach acid AKA muriatic acid) HBr hydrobromic acid HI hydroiodic acid 4) HClO4 perchloric acid (strongest of all acids) 5) HNO3 nitric acid (Used to make fertilizers & explosives) 6) H2SO4 sulfuric acid (Most produced chemical Worldwide, Car Battery Acid)

Base Definitions Arrhenius Base- any substance which releases OH- (hydroxide ions) in water. Reaction: MetalOH  Metal+ + OH- Bronsted(Lowry) Base- a proton(H+) acceptor. Reaction: X + HOH  HX+ + OH- This reaction is called hydrolysis of water rxn.

Properties of Bases Bases: 1) Bitter Taste 2) Turn litmus BLUE 3) Electrolytes-bases release ions in water 4) Corrosive-cause chemical burns 5) Bases dissolve animal protein(slippery, soap) 6) Acids + Bases  Salts + H2O

Strong Bases-completely (100%) ionize in water. There are 8 strong bases(All Arrhenius Bases): LiOH lithium hydroxide NaOH sodium hydroxide KOH potassium hydroxide RbOH rubidium hydroxide CsOH cesium hydoxide Ca(OH)2 calcium hydroxide Sr(OH)2 strontium hydroxide Ba(OH)2 barium hydroxide

pH Scale

pH Calculations Key equation: pH = -log[H+] pOH = - log[OH-] pH + pOH = 14.0 & [H+]x[OH-] = Kw(1.0 x 10-14)

pH calculation Find the [H+] of a 0.0025M HCl solution pH pOH [OH-]

pH calculation Find the [H+] of a 0.082M NaOH solution pH pOH [OH-]

0.0075 mol HNO3 are dissolved in 852 ml of solution. Find pH:

pH Calculations Solution pH pOH [H+] [OH-] [H3O+] Acidic/Basic 1 1.0 X 10-5M 2 3.00 3 1.0 X 10-12M 4 9.00 5 1.0 X 10-7M 6 6.2 X 10-11M 7 6.85 8 2.9 X 10-3M 9 12.41 10 7.0 X 10-5M

pH Calculations part II Solution pH pOH [H+] [OH-] [H3O+] Acidic/Basic 1 6.29 2 13.00 3 1.0 X 10-12M 4 9.00 X 10-8M 5 7.00 6 3.0 X 10-1M 7 1.85 X 10-5M 8 2.9 9 2.75 X 10-6M 10 9.0 X 10-11M

pH Review Find the pH if [OH-] = 3.6 x 10-11M:

Neutralization Reaction- the rxn between an acid + base  salt + water Most neutralization rxns are double replacement rxns between arrhenius acid + arrhenius base HX + MOH  MX + HOH HCl + Mg(OH)2  _____ + _____ H3PO4 + NaOH  _____ + _____ HClO4 + Ca(OH)2  _____ + _____ _______ + ________  Na2CO3 + H2O HC2H3O2 + Ba(OH)2  _______ + _____

Amphoteric- a substance which can act as either an acid(donate H+) or a base(accept H+). H2O is amphoteric: It can release a H+: HOH  H+ + OH- (hydroxide ion) It can accept a H+: HOH + H+  H3O+(hydronium ion) Amphoteric species can also form during the dissociation of a polyprotic acid: Acid proton Conj. Base H3PO4 ↔ H+ + H2PO4- H2PO4- ↔ H+ + HPO42- HPO42- ↔ H+ + PO43-

Titration- a reaction used to find the conc. of an unknown solution. If a titration is between an acid and a base: NaVa = NbVb N= normailty, N=M x #of equivalents(#H+’s or #OH-’s) V = volume Ex: What volume of 0.556M HCl will neutralize 50.0 mL of 0.335M Sr(OH)2?

38. 5 mL of 0. 750M H2SO4 neutralizes 50. 0 mL of NaOH 38.5 mL of 0.750M H2SO4 neutralizes 50.0 mL of NaOH. What is the molarity of NaOH? 20.0 mL of 1.25M KOH neutralizes 25.0 ml H2SO3. What is the molarity of acid?

Name___________ pH Review, Pre-AP Chemistry Solution pH pOH [H+] [OH-] [H3O+] Acidic/Basic 1 6.29 2 13.00 3 1.0 X 10-12M 4 Draw a detailed pH scale How many ml of 0.25M HCl will neutralize 25.0ml of 0.40M NaOH? What is the molarity of 325mL of Sr(OH)2 that neutralized 255 mL of 0.380 M H3PO4