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Acids  Taste sour  Reach with certain metals (Zn, Fe, etc.) to produce hydrogen gas  cause certain organic dyes to change color  react with limestone.

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Presentation on theme: "Acids  Taste sour  Reach with certain metals (Zn, Fe, etc.) to produce hydrogen gas  cause certain organic dyes to change color  react with limestone."— Presentation transcript:

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2 Acids  Taste sour  Reach with certain metals (Zn, Fe, etc.) to produce hydrogen gas  cause certain organic dyes to change color  react with limestone (CaCO3) to produce carbon dioxide  React with bases to form salts and water

3 Bases  Taste bitter  feel slippery or soapy  react with oils and grease  cause certain organic dyes to change color  react with acids to form salts and water

4 Similarities  Taste sour  Reacts with each other to form salts and waters  Causes certain organic dyes to change colors

5 Definitions of acids  A substance that produces Protons, H+

6 Definitions of bases  A substance that produces Hydroxide ions, OH-

7 Reactions of acids and bases with water  Acids and bases form ions in solution: HCl(aq) ® H + (aq) + Cl - (aq)  H 3 O + - hydronium ion H + and H 3 O + are equivalent in aq. solution  When we look at the reactions of acids - can be generalized using hydrogen ion  Reaction with zinc yields hydrogen gas  Reaction with limestone - produce CO2(g)  Acids react with bases to produce a salt  Similarly for bases, produce hydroxide ions

8 Neutralization and salts  Neutralization - one type of double replacement reaction  Acid + Base ® Salt + water  Net ionic equation shows what drives the neutralization reaction  example:  Molecular: HCl(aq) + NaOH(aq) ® NaCl(aq) + H2O(l)  Total Ionic: H+(aq) + Cl-(aq) + Na+(aq) + OH-(aq) ® Na+(aq) + Cl-(aq) + H2O(l)  Net Ionic: H+(aq) + OH-(aq) ® H2O(l)  SALT - a salt is formed from the anion of the acid and the cation of the base - usually present as spectator ions. - not always NaCl

9 Types of acids  Monoprotic - a solution that produces one mole of H+ ions per mole of acid HCl, HNO3  Diprotic - a solution that produces two moles of H+ ions per mole of acid H2SO4  Triprotic - a solution that produces three moles of H+ ions per mole of acid H3PO4  Polyprotic - two ore more H+ per mole of acid  V. Polyprotic acids:  can be Partially neutralized  acid salt - an ionic compound containing the anion with one or more hydrogens that can be neutralized with a base

10 Strengths of Acids and Bases  STRONG ACIDS Acids that are essentially 100% ionized in aqueous solutions ex: HCl, HNO3, HClO4 produce the maximum concentration of H+ [acid] = [H+]  WEAK ACIDS Acids that are partially ionized ( usually less than 5%) in equilibrium. HF + H2O(l) H3O+(aq) + F-(aq) The forward and the reverse reaction are occurring simultaneously most found as HF.  STRONG BASES those compounds that completely ionize in water to produce OH- ions NaOH(s) ® Na+(aq) + OH-(aq) Concentration of base = concentration of hydroxide ions  WEAK BASES NH3(aq) + H2O(l) NH4+(aq) + OH-(aq) equilibrium lies far to the left (mostly reactants present)

11 Equilibrium of Water  H2O(l) + H2O(l) H3O+(aq) + OH-(aq)  Autoionization - produces positive and negative ions from the dissociation of the molecules of a liquid.  Experimentally, found concentration of ions = 1.0 x 10-7 M at 25  C  [H3O+][OH-] = Kw  At 25  C (1.0 x 10-7)(1.0 x 10-7) = 1.0 x  Kw = ION PRODUCT - gives us the concentrations of hydronium and hydroxide ions in pure water and acidic and basic solutions  Neutral[H3O+] = [OH-] = 1.0 x 10-7 M  Acidic[H3O+] > 1.0 x 10-7, [OH-] <1.0 x 10-7  Basic[H3O+] 1.0 x 10-7

12 Brønsted-Lowry Acids and Bases  acid - a proton (H+) donor  base - a proton (H+) acceptor  NH3(aq) + H2O(aq)  NH4+(aq) + OH- (aq)  NH3 and NH4+ are conjugate acid-base pairs  H2O and OH- are conjugate acid-base pairs  Amphiprotic - a compound or ion that can either donate or accept H+ ions.  H2O, HSO4-, HPO42-, HSO3- etc.

13 Acidic and Basic Salt solutions  Hydrolysis - the reaction of an anion with water to produce OH- or the reaction of a cation to produce H3O+  Neutral solutions of salts: Cation does not undergo hydrolysis  Anion does not undergo hydrolysis  Basic solutions of salts: Cation same as above  Anion undergoes some hydrolysis  Acidic solutions of salts: Cation undergoes some hydrolysis  Anion does not  Complex solutions: Cation and anion undergoes hydrolysis  Then you need to know the relative strength of each.

14 . Predicating acid base reactions in water  Acid-Base reactions always yield conj. acid-base  Strong Acid : weak conj. base  Strong Base : weak conj. acid  Weak Acid : strong conj. base  Weak Base : strong conj. acid  The strength of the reactant compared to the strength in the product determines which direction the equilibrium lies.  Three predictions can be made:  The reactant may Not react at all, leaving essentially all reactants (negligible)  The reactants may Slightly react, leaving mostly reactants (limited)  The reactants may react (essentially) completely, leaving little or no reactants (favorable)

15 Buffer solutions  Buffer solution - resists changes in pH caused by the addition of limited amounts of a strong acid or a strong base.  A buffer solution must contain:  A weak acid + its conjugate base  or A weak base + its conjugate acid

16 Citation PAge  "Chapter 12 - Acids and Bases." Modesto Junior College. N.p.. Web. 16 Nov


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