Table 1: Data from titrationsQuestionsGateway General Chemistry 125/126/130Exam 3November 22, 20056:10-7:40 or 8:10-9:40 individual7:40-8:00 or 9:40-10:00 team problemName_______________________Lab GSI (Ryan or Tom) _____________Discussion GSI (Ryan or Tom) __________A periodic table is attached for use with the exam. You may remove it and do not need to turn it in with the exam.Page QuestionsPossiblepointsScore2 1-5 5 3 6-7 84 8-9 65 10 96 11 47 12 68 13 29-10 Team 10Total _______/501Please write the correct answer in the box next to each question (1 point each). 1. Consider the gas-phase equilibrium A ⇌ B. In a series of experiments, different initial amountsof A and B are mixed together, and the mixture in each case is allowed to come to equilibrium. Which one of these experiments would yield values for the amounts of A and B present at equilibrium different from all the other experiments?a. 3.0 moles A, 4.5 moles Bb. 4.5 moles A, 3.0 moles Bc. 1.5 moles A, 4.5 moles Bd. 7.5 moles A, no Be. 0.5 moles A, 7.0 moles B2. A weak acid is 5% ionized at equilibrium. Therefore we can say that the ionization reaction is _____-favored, because _____. a. product; the amount of products << the amount of reactants b. reactant; the amount of products << the amount of reactants c. reactant; the amount of products >> the amount of reactants d. product; the amount of products >> the amount of reactants e. neither; not enough information is available to reach a conclusion3. Consider the gas-phase equilibrium A ⇌ B. Certain amounts of A and B are mixed in a vessel. As they come to equilibriuma. the forward reaction rate declines and the reverse reaction rate rises.b. the reverse reaction rate declines and the forward reaction rate rises.c. both forward and reverse reaction rates decline.d. both forward and reverse reaction rates rise.e. either a. or b. above, but we cannot say which without more information.4. Once the reaction quotient, Q, has been determined for a reaction mixture, comparison with the value of the equilibrium constant, K, will determinea. if the mixture is at equilibrium or not.b. if the mixture has an excess of either products or reactants compared to equilibrium. c. if the mixture will react to the left, to the right, or not at all. d. Both a and b.e. All of a, b, and c.5. Which reaction illustrates water acting as a base?a. Cu(H2O)42+ + 4 NH3  Cu(NH3)42+ 4 H2Ob. H2CO3  H2O + CO2c. NH3 + H2O  NH4+ + OH-d. HPO4-2 + H2O  OH- + H3PO4e. HSO4- + H2O  H3O+ + SO42-21) 2) 3) 4) 5)6) (1 point) For the reaction 2A ⇌ 3B Kc = 1.377) (7 points) Given the equilibrium: HCN(aq) + H2O(l)  H3O+(aq) + CN-(aq) H >0; Ka = 4.0 x10-10What happens to the concentration of hydrogen cyanide [HCN] when the following stresses are placed on the system at equilibrium? (Circle the correct description of the [HCN] as a result of the stress described) [HCN]a) Temperature is raised increases decreases stays the sameb) NaCl is added increases decreases stays the samec) NaOH is added increases decreases stays the samed) NaCN is added increases decreases stays the samee) HCl is added increases decreases stays the samef) Water is added increases decreases stays the sameg) The following are mixed together:1x10-4M HCN 1x10-4 M CN- 5 x10-3 M H3O+increases decreases stays the same8) (2 points) According to Chemical and Engineering News (July 4, 2005 p21), if current CO2 emission trends continue, the oceans will become so acidic that corals will cease to thrive. The 3If the concentrations of A and B are equal at equilibrium, what is the value of that concentration?7 (1 point each box)1oceans are a sink for CO2 from fossil fuels, absorbing about half of emissions. When CO2 dissolves, it produces carbonic acid, which is corrosive to shells of marine organisms and can interfere with the oxygen supply of marine animals. In the past 200 years, the average pH of the surface seawater has declined from 8.3 to 8.2. What is the change in [H3O+] that this correspondsto?9) (4 points; 1/3 point per box) Fill in the following table:Write out any and all equilibria taking place when this molecule is dissolved in water. If there is no equilibrium, then write NONECircle the approximate pH ofthe resulting solutionNH4Cl pH <7 pH~7 pH >7NaCl pH <7 pH~7 pH >7HNO3 pH <7 pH~7 pH >7Ca(OH)2 pH <7 pH~7 pH >7KClO3 pH <7 pH~7 pH >7H3PO4 pH <7 pH~7 pH >744210) (9 points) Consider the salt sodium fluoride used to fluorinate drinking water. At levels of 1 ppm used for fluorinated water, there is not enough fluoride to affect the pH. However, at high concentrations (1.0 M NaF), the salt does affect the pH. What is the pH of 1.0 M solution of NaF? (Ka HF = 7.2 x10-4) b) Label the acid, base, conjugate acid, and conjugate base in the equilibrium above.5f) What is the pH?e) What are the concentrations of all of the ions present in solution (Na+, F-, OH-,, H3O+) at equilibrium?a) Write out the relevant equilibrium equation that show the ion that affects the pH:c) What is the expression for the equilibrium constant of the equilibrium that you wrote in a?d) What is the numerical value of the equilibrium constant?11114[Na+] = [F-] = [H3O+] = [OH-] = 111) (4 points) Potassium hydrogen phthalate also known as KHP (C8H5O4K) reacts with sodium hydroxide as shown below. KHP can be used to determine the concentration of a solution of sodium hydroxide through titration.COOHCOO- K++ NaOHCOO- Na+COO- K++ H2OKHPA titration is carried out by weighing dry KHP into a beaker, dissolving it in 75 mL of water, adding an indicator, and then titrating with NaOH until the endpoint is reached. The data obtained from three such titrations is recorded in Table 1.12) (4 points) For the reaction6a) What is the concentration of NaOH?b) What indicator could you use in this titration? Describe how you would know when you had reached the end-point.c) You can now use the NaOH solution to determine the concentration of acetic acid (CH3COOH) in as 20.01 mL sample of vinegar. It takes 102.3 mL of the NaOH solution frompart a to reach the end point. What is the molar concentration of acetic acid in vinegar?Table 1: Data from titrationsWeightKHP used (g)Volume ofNaOH used (mL)0.7023