CHEM 210 Exam 1 Review 2024 With Questions And Answers - Portage Learning.

CHEM 210 Exam 1 Review 2024 With Questions And Answers - Portage Learning. What is a BL acid? BL base? - Answer Acid is a proton donor while a base is proton acceptor List the 6 strong acids - Answer HClO4, HCl, HBr, HI, HNO3, H2SO4 List the 6 strong bases - Answer LiOH, NaOH, KOH, Ca(OH)2, Sr(OH)2, Ba(OH)2 What is the eq. for the dissociation of a weak acid? - Answer HA <=> H+ + AKa = ([H+][A-])/[HA] What is the eq. for base hydrolysis? - Answer B + H2O <=> BH+ + OHKb = ([BH+][OH-])/[B] What is the equation for pH and pOH? - Answer pH = -log[H+] pH + pOH = -log(Kw) = 14 pOH = -log10 [OH-] How would you convert pH to pOH and vice versa? - Answer pH = 14 - pOH pOH = 14 - pH How would you convert pH to [H3O+]? - Answer pH = - log[H3O+] [H3O+] = 10^-pH How would you convert [H3O+] to [OH-]? - Answer Kw = 1 x 10^-14 = [H3O+][OH-] Calculate the [OH-] in 6 M HNO3 and [H3O+] in 6.0 M NaOH at 25 C. - Answer Kw = [OH][H3O] = 1 x 10^-14 (1 x 10^-14) / 6.0 M = 1.7 x 10^-15 The pH of a seawater sample is 8.30 what is [H3O+]? - Answer [H3O+] = 10^-pH CHEM 210 Exam 1 Review 2024 With Questions And Answers - Portage Learning 10^-8.3 = 5.01 x 10^-9 An acid at a pH of 0 has an OH concentration of? - Answer 1 x10^-14 and an H+ concentration of 1 What is the Ka and pKa range for a very strong acid? Weak acid? Extremely weak? - Answer very strong: ka >0.1 pka <1 weak acid 10^-6 - 10^-3 pka 3-5 extremely < 10^-15 pka>15 Salt is the product of what rxn? - Answer Acid-base usually strong electrolytes that completely dissociate in water Strong acid - strong acid strong acid - weak base strong base - strong base weak acid - weak base Calculate the pH of 0.010 M solution of sodium hypochlorite (NaClO) The Ka is 2.9 x 10^-18 - Answer Kw = Kb x Ka Kb = Kw/ka kb = 3.45 x 10^-7 R ClO- + H2O <=> OH- + HClO I 0.010 C - X + X + X E 0.010 - X X X 0 = X^2 - 3.45 X 10^-7 X + 3.45 X 10^-9 quadratic eq. x = 5.86 x 10^-5 = [OH] -log[OH] = pOH pH = 14 - pOH pH = 9.77 What eq. are useful when working with weak acids and bases? - Answer HA <=> H+ + Aka = [H][A]/[HA] B + H2O <=> BH + OH Kb = [BH][OH]/[B] Calculate [H3O], pH, [HA], [A-], [OH], and alpha of .100 M propanoic acid (CH3CH2CO2H) pKa = 4.87 Ka = 1.34 x 10^-5 - Answer HA (aq) + H2O <-> H3O + AF - x x x Ka = [H3O][A]/[HA] = x^2 /(F-x) [H3O] = [A-] = x 1.34 x 10^-5 = x^2 /(0.010-x) quadratic eq. x = 1.151 x 10^-3 = [H3O] pH = -log(H3O) = 2.94 pOH = 14 - 2.94 [A-] = [H3O] [HA] = F - x = 0.01 - 1.151 x 10^-3 alapha = x/ F (100) = 1.151 x 10^-3/.01 (100) Calculate the [OH], [H3O], pH [BH], [B], and alpha of 0.1 M CH3NH2 Ka = 2.31 x 10 -11 - Answer B (aq) + H2O <-> BH + OHF - x x x Kb = [BH][OH]/[B] = x^2 /(F-x) [BH] = [OH] = x kb = kw/ka = 4.33 x 10^-4 x = (-Kb +sq rt(kb)^2 + 4(Kb)(F))/2 x = 6.367 x 10^-3 = [OH] = [BH] [H3O] = Kw/[OH] pH = -log [H3O] alpha = 6.367 x 10^-3 / 0.1 (100) [B] = 0.1 - 6.367 x 10^-3 What is charge balance? - Answer The sum of the positive charges in solution equals the sum of the negative charges in solution n1[C1] + n2[C2] = m1[A1] + m2[A2] C: concentration of cation n = charge of cation A: concentration of anion m = charge of anion What is mass balance? - Answer The quantity of all species in a solution containing a particular atom must equal the amount of that atom delivered to the solution What are the steps to the systematic approach to solving eq. problems? - Answer 1) Write all relevant eq. rxns and eq. constant expressions 2) count the unique species appearing in the eq. constant expressions; these are the unknowns. If the number of unknowns equalts the number of eq. constant expressions then have enough information to solve. If not add a mass balance eq. and or charge balance eq. Continue adding until the number of equations = the number of unknowns 3) combine eq. and solve for one unknown 4) check assumptions.