Exam 1 Chapter 15 17 4 Chemical and Solubility Equilibria Chem 1202 Form 3 Fall 2024 Dr Gasery Answer Key Instructions Use an 8 5 x 11 inch green and white scantron On Side Two of the scantron 1 Print your Last Name then First Name and bubble it in 2 Print and bubble in your complete correct LSU ID number 89 number 3 Bubble 3 in the Grade or Education box On Side One of the scantron sheet using a pencil blank 1 Print your name 2 Answers to the exam questions must go on side one Bubble the answers on the scantron 3 There is exactly one best answer for each question and you should NOT leave a question 4 On a numerical question choose the response closest to the correct answer This exam is closed notes and closed book You are not allowed to use your own scratch paper Only a scientific calculator is allowed during the exam NO graphing calculators Mark your answers in your Exam for future reference You can keep your Exam for further study Present your LSU ID and the front of your exam when submitting your scantron Useful Information and Constants The periodic table is located at the back of the exam R 0 08206 L atm mol K Kp Kc RT n 1 1 The following statements deal with the concepts of the equilibrium constant and reaction quotient Which statement is TRUE a A reaction quotient is the same as an equilibrium constant b If Q K the reaction must progress forward to reach equilibrium c If Q K the reaction is already at equilibrium d As a reaction progresses forward to reach equilibrium K is the lowest value Q can have e In a reacting mixture K is the ratio of reactant to product concentrations 2 Consider the following reaction at equilibrium 2IBr g I2 g Br2 g At 2000 K the Keq of the reaction is 9 0 What is the value of Keq for the following reaction 3Br2 g 3I2 g 6IBr g a 0 11 b 1 37 x 10 3 c 64 d 1 22 x 10 4 e 3 33 x 10 4 3 Consider the following reaction at equilibrium PCl5 g PCl3 g Cl2 g If the Kp of the reaction is 2 50 at 500 C calculate Kc for the reaction at this same temperature a 6 09 x 10 2 b 3 94 x 10 2 c 0 651 d 0 102 e 3 89 x 10 4 4 Gaseous NOCl is placed in a closed container at 300 C where it partially decomposes to NO and Cl2 in the following equilibrium 2NOCl g 2NO g Cl2 g At equilibrium it is found that PNOCl 0 50 atm PNO 0 10 atm and PCl2 0 40 atm What is the value of Kp at this temperature a 0 08 b 0 16 c 0 016 d 6 25 e 12 5 5 What is the molar solubility of BaSO4 in water at 25 C The Ksp of BaSO4 at this temperature is 1 10 x 10 11 a 1 05 x 10 5 b 1 85 x 10 7 c 5 50 x 10 11 d 2 85 x 10 3 e 2 14 x 10 5 There was a typo with the Ksp value here It should have been 1 10 x 10 10 If you did NOT put a as the answer I gave you the points back 2 6 For the reaction below which of the following changes will shift the equilibrium to the right toward the formation of more products 4NH3 g 5O2 g 4NO g 6H2O g H 904 kJ a Increasing the volume of the reaction vessel b Increasing the temperature c Adding more water vapor d Removing O2 g e The total pressure of the system is increased by adding 1 atm of Ne g to the reaction 7 Which of these expressions correctly expresses the solubility product constant for vessel Ag3PO4 in water a Ag 3 PO4 b Ag PO4 c Ag 3 PO4 d Ag PO4 e Ag 3 PO4 3 3 3 3 3 3 8 You add 10 0 grams of solid copper II phosphate Cu3 PO4 2 to a beaker and then add 100 0 mL of water to the beaker at T 298 K The solid does not appear to dissolve You wait a long time with occasional stirring and eventually measure the equilibrium concentration of Cu2 aq in the water to be 5 01 x 10 8 M What is the Ksp of copper II phosphate a 5 01 x 10 8 b 2 50 x 10 15 c 4 20 x 10 15 d 3 16 x 10 37 e 1 40 x 10 37 9 Consider the reaction N2 g 2O2 g 2NO2 g How does each of the following changes impact the partial pressure of NO2 at equilibrium i Addition of more N2 to the reaction vessel will the partial pressure of NO2 at ii Removing O2 from the reaction vessel will the partial pressure of NO2 at iii Adding a catalyst to the reaction vessel will the partial pressure of NO2 at equilibrium equilibrium equilibrium a Increase decrease increase b Leave unchanged increase decrease c Decrease increase leave unchanged d Increase decrease leave unchanged e Decrease leave unchanged increase 3 10 Based on LeChatelier s principle which one of the following reactions will make more reactants if the overall pressure is increased a N2 g 3H2 g b I2 g Br2 g c 2HCl g d N2O4 g e 3H2S g 2Fe s 2NH3 g 2IBr g H2 g Cl2 g 2NO2 g Fe2S3 s 3H2 g Use the information about the following equilibrium to answer questions 11 14 below Consider the following reaction CO g 2H2 g CH3OH g A closed system initially contains 0 50 M CO 2 00 M H2 and 10 0 M CH3OH At equilibrium it is found that the concentration of H2 is 8 00 M 11 Choose the correct expression for Keq and description homogeneous or heterogeneous for the above reaction a Keq CH3OH 2 H2 2 CO 2 This reaction is heterogeneous b Keq CH3OH 2 H2 2 CO 3 This reaction is homogeneous c Keq CH3OH CO H2 2 This reaction is homogeneous d Keq CH3OH CO H2 2 This reaction is heterogeneous e Keq CO H2 2 CH3OH This reaction homogeneous 12 What is the concentration of CO at equilibrium 13 What is the concentration of CH3OH at equilibrium 14 What is the Keq for the reaction a 1 50 M b 6 50 M c 4 00 M d 3 50 M e 2 00 M a 5 00 M b 4 50 M c 2 00 M d 7 00 M e 3 50 M a 0 75 b 3 24 c 0 025 d 0 18 e 0 031 4 15 The following statements deal with the concept of equilibrium Which statement is FALSE a Reactants are still transformed into products even at equilibrium b At equilibrium all reactions stop c …