Principles of Chemistry II © Vanden BoutLet’s think about AcidsPrinciples of Chemistry II © Vanden BoutWhich of the following is amphiprotic?! A.! ! H3PO4 ! B.! ! NaH2PO4 !C.!!K3PO4!! D.! ! NaCl! E.! ! Na3PO4What is in solution?Principles of Chemistry II © Vanden BoutIf I add 0.1 moles of NaOH to 0.07 moles of H3PO4 what will be the dominant species in solution?! A.! ! H3PO4 and H2PO4-! B.! ! H2PO4- !C.!!H2PO4- and HPO42-!! D.! ! HPO42-! E.! ! HPO42- and PO43--What is in solution?Principles of Chemistry II © Vanden BoutIf I add 0.1 moles of NaOH to 0.07 moles of H3PO4 how would I solve for the pH! A.! ! It will be a weak acid! B.! ! It will be amphiprotic between Ka1 and Ka2! C.! ! It will be a buffer around Ka1!! D.! ! It will be a buffer around Ka2! E.! ! It will be a weak baseHow would I find the pHPrinciples of Chemistry II © Vanden BoutIf I add 0.15 moles of NaOH to .05 moles of H3PO4 how would I solve for the pH! A.! ! It will be a weak acid! B.! ! It will be amphiprotic between Ka1 and Ka2! C.! ! It will be a buffer around Ka1!! D.! ! It will be a buffer around Ka2! E.! ! It will be a weak baseHow would I find the pHPrinciples of Chemistry II © Vanden BoutTitration of H2CO3What is (are) the dominant species at pH = 6?A. H2CO3/HCO3- B. HCO3- C. HCO3- /CO32- D. CO32-Principles of Chemistry II © Vanden BoutWhich of the following will form a buffer?! A.! ! 100 mL of 1M HCl and 100 mL 1M of NaF! B.! ! 100 mL of 1M HCl and 50 mL of 1M NaOH! C.! ! 100 mL of 1M HCl and 50 mL of 1M NaCl!! D.! ! 100 mL of 1M HCl and 50 mL of 1M NH3! E.! ! 100 mL of 1M HCl and 200 mL of 1M Na(CH3COO)Recognizing a bufferPrinciples of Chemistry II © Vanden BoutWhich of the following will form a buffer?! A.! ! 100 mL of 1M HCl and 100 mL 1M of NaF! B.! ! 100 mL of 1M HCl and 50 mL of 1M NaOH! C.! ! 100 mL of 1M HCl and 50 mL of 1M NaCl!! D.! ! 100 mL of 1M HCl and 50 mL of 1M NH3! E.! ! 100 mL of 1M HCl and 200 mL of 1M Na(CH3COO)Solubility and Acids and BasesPrinciples of Chemistry II © Vanden BoutRolaids® contain about 0.1 g of Magnesium HydroxideWhy in the world would you ever put such a thing in your mouth? ! A.! ! 0.1 g is nothing. I eat 10-20 g NaOH daily just for laughs! B.! ! Acids are dangerous by bases as quite safe ! C.! ! The saliva in my mouth is acidic enough to "handle it"! D.! ! Mg(OH)2 is not soluble in waterPrinciples of Chemistry II © Vanden BoutSolubility EquilibriaMg(OH)2 (s) Mg2+(aq) + 2OH-(aq)Ksp = [Mg2+][OH-]2 = 5.6 x 10-12OH- that is dissolved neutralizes any H+then more OH- dissolves...repeatend result is a very slightly basic solutionPrinciples of Chemistry II © Vanden BoutWhat happens in our bubbling experimentto make the solution clear?! A.! ! the indicator dye evaporates! B.! ! the solution becomes more acidic! C.! ! the solution becomes more alkaline (basic)!! D.! ! the solution becomes too dilute to see the colorPrinciples of Chemistry II © Vanden BoutThinking about acid/base chemistrypKa = 5.2 Methyl RedHA Red A- Yellow pH > 5.2YellowRed< 1 pH < 5.2YellowRed> 1 -Principles of Chemistry II © Vanden BoutWhat happens in our bubbling experimentto make the solution clear?! A.! ! the indicator dye evaporates! B.! ! the solution becomes more acidic! C.! ! the solution becomes more alkaline (basic)!! D.! ! the solution becomes too dilute to see the colorPrinciples of Chemistry II © Vanden BoutWhat makes the solution acidic?! A.! ! dissolved oxygen gas! B.! ! dissolved nitrogen gas! C.! ! dissolved carbon dioxide gas!! D.! ! salivaPrinciples of Chemistry II © Vanden BoutWhat is one consequence of increased CO2 in the Earth’s atmosphere?! A.! ! oceans becoming more acidic! B.! ! oceans becoming more alkaline (basic)Principles of Chemistry II © Vanden BoutWhat makes the solution acidic?CO2(g) CO2(aq)CO2(aq) + H2O(l) H2CO3(aq)H2CO3(aq) HCO3-(aq) + H+(aq)HCO3-(aq) CO32-(aq) + H+(aq)CO32-(aq) + Ca2+(aq) CaCO3(s)Principles of Chemistry II © Vanden BoutIn Austin (an most places) water out of the tap is! A.! ! neutral! B.! ! slightly acidic! C.! ! slightly basic!Principles of Chemistry II © Vanden BoutIn Austin (an most places) water out of the tap is! A.! ! neutral! B.! ! slightly acidic! C.! ! slightly basic!because the ground if full of limestone (CaCO3)Principles of Chemistry II © Vanden BoutWhat makes the solution acidic?CO2(aq) CO2(g) H2CO3(aq) CO2(aq) + H2O(l) HCO3-(aq) + H+(aq) H2CO3(aq) CO32-(aq) + H+(aq) HCO3-(aq) CaCO3(s) CO32-(aq) + Ca2+(aq)Principles of Chemistry II © Vanden Bout! A.! ! H+! B.! ! H2CO3 and HCO3-! C.! ! only HCO3-! D.! ! HCO3- and CO32-! E.! ! only CO32-If I add alot of NaHCO3 to an HCl solutionthe predominate species in solution will bePrinciples of Chemistry II © Vanden BoutH2CO3(aq) HCO3-(aq) + H+(aq)HCO3-(aq) CO32-(aq) + H+(aq)pKa1 = 6.3pKa2 = 10.3The pH of my “solution” will be! A.! ! around 3! B.! ! around 6! C.! ! around 8! D.! ! around
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