<p> Leader: Olivia Exam 2 Review Course: Chem 178 Supplemental Instruction Instructor: Miller Iowa State University Date:</p><p>The position of equilibrium for the reaction</p><p>ZnO(s) + H2(g) Zn(s) + H2O(g) does not depend upon which of the following (pick multiple): (1) concentration of ZnO(s) (2) concentration of H2(g) (3) concentration of Zn(s) (4) concentration of H2O(g) (5) the value of Kc?</p><p>Which way will the following reactions, initially at equilibrium, shift when the temperature is decreased at constant pressure?</p><p>1.) 2C2H2(g) + 5O2(g) 4CO2(g) + 2H2O(l) ΔH = -1297 kJ 2.) CO2(g) O2(g) + C(s) ΔH = +393 kJ 3.) 4Fe(s) + 3O2(g) 2Fe2O3(s) ΔH = -1644 kJ</p><p>A substances that donates a proton in a chemical reaction can be described as: a.) Bronsted-Lowry acid b.) Bronsted-Lowry base c.) Conjugate base d.) Arrhenius acid e.) Arrhenius base</p><p>A solution with a [OH-] = 5.5x10-5 at 25 0C is a.) Acidic b.) Basic c.) Neutral</p><p>Calculate the pH in the above problem.</p><p>What is the value of Kc for the following reaction if the equilibrium concentrations are [A] = 0.60 M [B] = 0.35 M [C] = 0.55 M? </p><p>2 A (aq) + B (aq) ⇌ 2 C (aq)</p><p>1060 Hixson-Lied Student Success Center v 515-294-6624 v [email protected] v http://www.si.iastate.edu Initially 0.035 moles of SO2, 0.5 moles of SO2Cl2, and 0.08 moles of Cl2 are combined in a 5 liter flask. What is the value of Q and which direction will the reaction proceed to establish equilibrium?</p><p>SO2Cl2 (g) ⇄ SO2 (g) + Cl2 (g) Kc = 0.078</p><p>Which of these conjugate acid-base pairs will NOT function as a buffer? - a. CH3COOH and CH3COO b. HCl and Cl- - 2- c. HCO3 and CO3 d. All of the above will function as a buffer</p><p>Which one of the following binary compounds would you expect to be the most acidic? a. H2S or HCl b. HBr or HF c. HClO4 or HClO3</p><p>Label the following as a SA, WA, or negligible and write its conjugate base. a. HCOOH b. HF c. + NH4</p><p>The pH of a 0.15 M weak base B is 9.25. What is Kb for B? B is an arbitratry weak base, use the equation: B (aq) + H2O(l) equil BH+ (aq) + OH- (aq)</p><p>-5 -8 Given the Kb for ammonia is 1.8x10 and for hydroxylamine is 1.1x10 , which is the stronger base? a. Which conjugate acid is stronger?</p><p> b. Calculate the Ka for the conjugate acids Which of the following 0.1 M solutions has the smallest pH? a. NH4Cl b. NaNO3 c. BaI2 d. NH3 e. Na2ClO3</p><p>-8 Determine the pH of an initial 0.95 M solution of HOCl (Ka= 3.0x10 )</p><p>-5 What is the pH of a solution containing 0.8M NH3 and 1.0M of NH4Cl? Kb(NH3)=1.77x10</p><p>You are asked to prepare a pH=4.00 buffer starting from 1.50 L of 0.0200 M solution of benzoic acid (C6H5COOH) and any amount of sodium benzoate (C6H5COONa) in 1.20 L. a. What is the pH of the benzoic acid solution prior to adding sodium benzoate?</p><p> b. How many gram of sodium benzoate should be added to prepare the buffer?</p><p>The ______the acid, the ______the conjugate base.</p><p>The ______the pKa of the conjugate acid, the ______the base.</p><p>Acidity _____ with increasing positive charge on an atom. Across the periodic table acidity increases with ______, down the periodic table acidity increases with ______.</p><p>Classify the solutions as acids or bases.</p><p>Rank these acids from weakest to strongest:</p><p>- - CF3COOH HCO3 H2PO4 CH3COOH</p><p>What structural features of a molecule may effect the pKa of an acid?</p><p>Calculate the pH of a buffer that is 0.105 M in NaHCO3 and 0.125 M in Na2CO3.</p><p>Calculate the pH of a buffer formed by mixing 65 mL of 0.20 M NaHCO3 with 75mL of 0.15 M of Na2CO3.</p>