CHEM1901/3 Answers to Problem Sheet 10
|
|
- Sharlene Byrd
- 7 years ago
- Views:
Transcription
1 CHEM1901/3 Answers to Problem Sheet 10 1 (a) Al(s) Al 3+ (aq) Sn 2+ (aq) Sn(s) The half reactions and potentials are: Sn 2+ (aq) + 2e - Sn(s) Al 3+ (aq) + 3e - Al(s) E = 014 V E = 168 V The Al(s) Al 3+ (aq) half cell is on the left so this is the oxidation half cell so the half cell reaction is reversed The Sn 2+ Sn(s) half cell is on the right so is the reduction half cell (i) Al(s) Al 3+ (aq) + 3e - E = 168 V (ii) Sn 2+ (aq) + 2e - Sn(s) E = 014 V To balance the electrons, these must be combined with 2 (i) and 3 (ii): 2Al(s) + 3Sn 2+ (aq) 2Al Sn(s) E = {(+168) + (014)} V = 154 V Al(s) is the reductant and Sn 2+ (aq) is the oxidant Pt(s) Fe 2+ (aq), Fe 3+ (aq) Ag + (aq) Ag(s) The half reactions and potentials are: Fe 3+ (aq) + e - Fe 2+ (aq) Ag + (aq) + e - Ag(s) E = 077 V E = 080 V The Pt(s) is an inert electrode in contact with the Fe 2+ (aq), Fe 3+ (aq) solution This half is on the left so is the oxidation half cell, so the half cell reaction is reversed The Ag + (aq) Ag(s) half cell is on the right so is the reduction half cell (i) Fe 2+ (aq) Fe 3+ (aq) + e - E = 077 V (ii) Ag + (aq) + e - Ag(s) E = 080 V These can then be combined to give the overall cell reaction: Fe 2+ (aq) + Ag + (aq) Fe 3+ (aq) + Ag(s) E = {(077) + (+080)} V = +003 V Fe 2+ (aq) is the reductant Ag + (aq) is the oxidant (c) Pt(s) MnO 4 (aq), H + (aq), Mn 2+ (aq) Sn 4+ (aq), Sn 2+ (aq) Pt(s) The half reactions and potentials are: MnO - 4 (aq) + 8H + (aq) + 5e - Mn 2+ (aq) + 4H 2 O(l) Sn 4+ (aq) + 2e - Sn 2+ (aq) E = 151 V E = 015 V
2 The Pt(s) is an inert electrode in contact with the MnO 4 - (aq), Mn 2+ (aq) solution This half is on the left so is the oxidation half cell, so the half cell reaction is reversed The Sn 4+ (aq) Sn 2+ (aq) half cell is on the right so is the reduction half cell (i) Mn 2+ (aq) + 4H 2 O(l) MnO - 4 (aq) + 8H + (aq) + 5e - E = 151 V (ii) Sn 4+ (aq) + 2e - Sn 2+ (aq) E = 015 V To balance the electrons, these must be combined with 2 (i) and 5 (ii): These can then be combined to give the overall cell reaction: 2Mn 2+ (aq) + 8H 2 O(l) + 5Sn 4+ (aq) 2MnO 4 - (aq) + 16H + (aq) + 5Sn 2+ (aq) E = {(151) + (+015)} V = 136 V Mn 2+ (aq) is the reductant Sn 4+ (aq) is the oxidant As E < 0, the cell reaction is not spontaneous as written and will occur in the opposite direction with MnO 4 - oxidising Sn 2+ (aq) 2 (a) Mg(s) Mg 2+ (aq) + 2e - (aq) Pb 2+ (aq) + 2e - (aq) Pb(s) E = 236 V (reversed as oxidation required) E = 013 V The overall reaction is: Mg(s) + Pb 2+ (aq) Mg 2+ (aq) + Pb(s) E = {(236) + (013)} V = +223 V As E > 0, the reaction should occur Sn(s) Sn 2+ (aq) + 2e - 2H + (aq) + 2e - H 2 (g) E = +014 V (reversed as oxidation required) E = 000 V (by definition) The overall reaction is: Sn(s) + 2H + (aq) Sn 2+ (aq) + H 2 (g) E = {(+014) + (000)} V = +014 V As E > 0, the reaction should occur (c) SO 2-4 (aq) + 4H + (aq) + 2e - SO 2 (g) + 2H 2 O(l) E = +020 V Sn 2+ (aq) Sn 4+ (aq) + 2e - E = 015 V (reversed as oxidation required) Balancing the electrons gives the overall reaction as: SO 4 2- (aq) + 4H + (aq) + Sn 2+ (aq) SO 2 (g) + 2H 2 O(l) + Sn 4+ (aq) The cell potential is E = {(+020) + (015)} V = +005 V As E > 0, the reaction should occur but the value is very small so an equilibrium
3 mixture will form (d) MnO - 4 (aq) + 8H + (aq) + 5e - Mn 2+ (aq) + 4H 2 O(l) E = 151 V H 2 O 2 (aq) O 2 (g) + 2H + (aq) + 2e - E = 070 V (reversed as oxidation required) Balancing the electrons gives the overall reaction as: 2MnO 4 - (aq) + 16H + (aq) + 5H 2 O 2 (aq) 2Mn 2+ (aq) + 8H 2 O(l) + 5O 2 (g) + 10H + (aq) From this, the H + (aq) on the right hand side can be cancelled: 2MnO 4 - (aq) + 6H + (aq) + 5H 2 O 2 (aq) 2Mn 2+ (aq) + 8H 2 O(l) + 5O 2 (g) The cell potential is E = {(+151) + (070)} V = +081 V As E > 0, the reaction should occur 3 (a) Sn 2+ (aq) + 2Ag + (aq) Sn 4+ (aq) + 2Ag(s) K eq = 4+ [Sn (aq)] [Sn (aq)][ag (aq)] Sn 2+ (aq) Sn 4+ (aq) + 2e - Ag + (aq) + e - Ag(s) E = 015 V (reversed as oxidation required) E = +080 V Hence, E = ((-015) + (080)) V = 065 V RT E = 2303log( Kc ), the equilibrium constant at T = 298 K is: nf K 2303 ( ) ( ) 21 c =10 nfe RT =10 =96 10 MnO 2 (s) + 4H + (aq) + 2Cl (aq) Mn 2+ (aq) + 2H 2 O(l) + Cl 2 (g) K eq = [Mn 2+ (aq)][cl 2(g)] [H (aq)] [Cl (aq)] MnO 2 (s) + 4H + (aq) + 2e - Mn 2+ (aq) + 2H 2 O(l) E = 123 V 2Cl - (aq) Cl 2 (g) + 2e - E = 36 V (reversed as oxidation required) Hence, E = ((123) + (36)) V = -013 V RT E = 2303log( Kc ), the equilibrium constant at T = 298 K is: nf
4 K 2303 ( ) ( ) -5 c =10 nfe RT =10 = (a) Al(s) Al 3+ (018 M) Fe 2+ (085 M) Fe(s) Al(s) Al 3+ (aq) + 3e - E = 168 V (on the left so oxidation half cell) Fe 2+ (aq) + 2e - Fe(s) E = 044 V Hence, E = ((+168) + (-044)) V = 124 V The overall reaction is 2Al(s) + 3Fe 2+ (aq) 2Al 3+ (aq) + 3Fe(s) which involves 6e - and has Q = 3+ 2 [Al (aq)] 2+ 3 [Fe (aq)] Using the Nernst equation, RT Ecell = E - log( Q) nf 2303 (8314 J K mol ) (298 K) (018) = (124 V) - log ( C mol ) (085) = 125 V 2 3, Ag(s) Ag + (034 M) Cl 2 (g, 055 atm) Cl (0098 M) Pt(s) Ag(s) Ag + (aq) + e - E = 080 V (on the left so oxidation half cell) Cl 2 (g) + 2e - 2Cl - (aq) E = 136 V Hence, E = ((-080) + (+136)) V = 056 V The overall reaction is 2Ag(s) + Cl 2 (g) 2Ag + (aq) + 2Cl - (aq) which involves 2e - and has Q = [Cl 2(g)] [Ag (aq)] [Cl (aq)] The pressure of Cl 2 (g) is given as 055 atm Using the ideal gas law PV = nrt or n P (055 atm) concentration = = = = M V RT ( L atm K mol ) (298) K Using the Nernst equation, RT Ecell = E - log( Q) nf (8314 J K mol ) (298 K) (034) (0098) = (056 V) - log, ( C mol ) (00225) = 057 V
5 5 The relevant half cell reactions and reduction potentials are: Cu 2+ (aq) + 2e - Cu(s) Fe 2+ (aq) + 2e - Fe(s) Sn 4+ (aq) + 2e - Sn 2+ (aq) Ag + (aq) + e - Ag(s) Zn 2+ (aq) + 2e - Zn(s) Fe 2+ (aq) + 2e - Fe(s) E = 034 V E = 044 V E = 015 V E = 080 V E = 076 V E = 044 V In each case, the half reaction with the lowest electrode potential is reversed (a) (i) For the first cell: The Fe(s) Fe 2+ (aq) cell is reversed giving the overall cell reaction: Fe(s) + Cu 2+ (aq) Fe 2+ (aq) + Cu(s) (ii) Reduction occurs at the cathode: Cu(s) Cu 2+ (aq) half cell Oxidation occurs at the anode: Fe(s) Fe 2+ (aq) half cell (iii) (iv) (i) Electrons flow from the anode to the cathode: from the Fe(s) Cu(s) electrode E = ((034) + (+044)) V = +078 V For the second cell: The Pt Sn 4+ (aq), Sn 2+ (aq) cell is reversed giving the overall cell reaction: Sn 2+ (aq) + 2Ag + (aq) Sn 4+ (aq) + Ag(s) (ii) Reduction occurs at the cathode: Ag(s) Ag + (aq) half cell Oxidation occurs at the anode: Pt Sn 4+ (aq), Sn 2+ (aq) half cell (iii) (iv) (c) (i) Electrons flow from the anode to the cathode: from the Pt(s) Ag(s) electrode E = ((080) + (015)) V = +065 V For the third cell: The Zn Zn 2+ (aq) cell is reversed giving the overall cell reaction: Zn(s) + Fe 2+ (aq) Zn 2+ (aq) + Fe(s) (ii) Reduction occurs at the cathode: Fe(s) Fe 2+ (aq) half cell Oxidation occurs at the anode: Zn Zn 2+ (aq) half cell (iii) (iv) Electrons flow from the anode to the cathode: from the Zn(s) Fe(s) electrode E = ((044) + (076)) V = +032 V
6 As the concentrations are not standard, the Nernst equation must be used to calculate the cell potential The reaction involves the movement of 2 electrons At 298 K, E cell is: = 0 RT Ecell E log( Q) nf (8314 J K mol ) (298 K) 01 = (032 V) 2303 log( ) = 026 V ( C mol ) Reduction takes places at the cathode: Mg 2+ (l) + 2e - Mg(s) Oxidation takes places at the anode: Cl - (l) ½ Cl 2 + e - 7 The molar mass of Cl 2 (g) is (2 3545) g mol = 709 g mol so 1000 kg corresponds to g = mol 709 g mol The half cell for chlorine is Cl 2 (g) + 2e - 2Cl - (aq) so the number of moles of electrons required is ( ) mol = mol The charge on this amount of electrons is 28200F The time required to deliver this charge with a current of A is therefore: t = Q I 28200F = = s = 252 hours ( A) The volume occupied by mol of Cl 2 can be obtained using the ideal gas equation PV = nrt: V = nrt (14100 mol) ( L atm K mol ) (298 K) = = L P (100 atm) 8 (a) Dipole-dipole and dispersion forces are acting between the molecules in these compounds
7 The electronegativity of the halogens decreases in the order F > Cl > Br so the polarity of the bonds decreases in the order C-F > C-Cl > C-Br, as shown by the dipole moments The dipole-dipole interactions are therefore largest in CH 2 F 2 However, dispersion forces increase with the size of the electron cloud and, hence, with the atomic number These are therefore largest in CH 2 Br 2 The dispersion forces must be more important than the dipole-dipole interactions in these compounds so the boiling points increase in the order CH 2 F 2 < CH 2 Cl 2 < CH 2 Br 2 9 A and C presence of OH groups will lead to H-bonding interactions B delocalized π electron density will lead to dispersion interactions D charged group with N-H bonds will lead to interaction with ions and polar groups
Ch 20 Electrochemistry: the study of the relationships between electricity and chemical reactions.
Ch 20 Electrochemistry: the study of the relationships between electricity and chemical reactions. In electrochemical reactions, electrons are transferred from one species to another. Learning goals and
More informationK + Cl - Metal M. Zinc 1.0 M M(NO
Redox and Electrochemistry This section should be fresh in your minds because we just did this section in the text. Closely related to electrochemistry is redox chemistry. Count on at least one question
More informationElectrochemistry Worksheet
Electrochemistry Worksheet 1. Assign oxidation numbers to each atom in the following: a. P 4 O 6 b. BiO 3 c. N 2 H 4 d. Mg(BrO 4 ) 2 e. MnSO 4 f. Mn(SO 4 ) 2 2. For each of the reactions below identify
More informationChemistry 122 Mines, Spring 2014
Chemistry 122 Mines, Spring 2014 Answer Key, Problem Set 9 1. 18.44(c) (Also indicate the sign on each electrode, and show the flow of ions in the salt bridge.); 2. 18.46 (do this for all cells in 18.44
More informationReview: Balancing Redox Reactions. Review: Balancing Redox Reactions
Review: Balancing Redox Reactions Determine which species is oxidized and which species is reduced Oxidation corresponds to an increase in the oxidation number of an element Reduction corresponds to a
More informationPreliminary Concepts. Preliminary Concepts. Class 8.3 Oxidation/Reduction Reactions and Electrochemistry I. Friday, October 15 Chem 462 T.
Class 8.3 Oxidation/Reduction Reactions and Electrochemistry I Friday, October 15 Chem 462 T. Hughbanks Preliminary Concepts Electrochemistry: the electrical generation of, or electrical exploitation of
More informationChem 1721 Brief Notes: Chapter 19
Chem 1721 Brief Notes: Chapter 19 Chapter 19: Electrochemistry Consider the same redox reaction set up 2 different ways: Cu metal in a solution of AgNO 3 Cu Cu salt bridge electrically conducting wire
More informationPotassium ion charge would be +1, so oxidation number is +1. Chloride ion charge would be 1, so each chlorine has an ox # of -1
Chapter 18-1 1. Assign oxidation numbers to each atom in: Ni Nickel ion charge would be +2, so oxidation number is +2 Chloride ion charge would be 1, so each chlorine has an ox # of -1 Mg 2 Ti 4 Magnesium
More information2. Write the chemical formula(s) of the product(s) and balance the following spontaneous reactions.
1. Using the Activity Series on the Useful Information pages of the exam write the chemical formula(s) of the product(s) and balance the following reactions. Identify all products phases as either (g)as,
More informationElectrochemistry - ANSWERS
Electrochemistry - ANSWERS 1. Using a table of standard electrode potentials, predict if the following reactions will occur spontaneously as written. a) Al 3+ + Ni Ni 2+ + Al Al 3+ + 3e - Al E = -1.68
More information5.111 Principles of Chemical Science
MIT OpenCourseWare http://ocw.mit.edu 5.111 Principles of Chemical Science Fall 2008 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms. Page 1 of 10 pages
More informationChapter 13: Electrochemistry. Electrochemistry. The study of the interchange of chemical and electrical energy.
Chapter 13: Electrochemistry Redox Reactions Galvanic Cells Cell Potentials Cell Potentials and Equilbrium Batteries Electrolysis Electrolysis and Stoichiometry Corrosion Prevention Electrochemistry The
More informationCHAPTER 21 ELECTROCHEMISTRY
Chapter 21: Electrochemistry Page 1 CHAPTER 21 ELECTROCHEMISTRY 21-1. Consider an electrochemical cell formed from a Cu(s) electrode submerged in an aqueous Cu(NO 3 ) 2 solution and a Cd(s) electrode submerged
More informationName AP CHEM / / Collected Essays Chapter 17 Answers
Name AP CHEM / / Collected Essays Chapter 17 Answers 1980 - #2 M(s) + Cu 2+ (aq) M 2+ (aq) + Cu(s) For the reaction above, E = 0.740 volt at 25 C. (a) Determine the standard electrode potential for the
More informationElectrochemistry Voltaic Cells
Electrochemistry Voltaic Cells Many chemical reactions can be classified as oxidation-reduction or redox reactions. In these reactions one species loses electrons or is oxidized while another species gains
More informationAP Chemistry 2010 Free-Response Questions Form B
AP Chemistry 010 Free-Response Questions Form B The College Board The College Board is a not-for-profit membership association whose mission is to connect students to college success and opportunity. Founded
More informationAP Chemistry 2010 Scoring Guidelines Form B
AP Chemistry 2010 Scoring Guidelines Form B The College Board The College Board is a not-for-profit membership association whose mission is to connect students to college success and opportunity. Founded
More information1332 CHAPTER 18 Sample Questions
1332 CHAPTER 18 Sample Questions Couple E 0 Couple E 0 Br 2 (l) + 2e 2Br (aq) +1.06 V AuCl 4 + 3e Au + 4Cl +1.00 V Ag + + e Ag +0.80 V Hg 2+ 2 + 2e 2 Hg +0.79 V Fe 3+ (aq) + e Fe 2+ (aq) +0.77 V Cu 2+
More informationCHM1 Review Exam 12. Topics REDOX
CHM1 Review Exam 12 Topics REDOX REDOX Reactions Oxidation Reduction Oxidizing agent Reducing agent Galvanic (Voltaic) Cells Anode Cathode Salt bridge Electrolyte Half-reactions Voltage o Positive voltages
More informationGalvanic cell and Nernst equation
Galvanic cell and Nernst equation Galvanic cell Some times called Voltaic cell Spontaneous reaction redox reaction is used to provide a voltage and an electron flow through some electrical circuit When
More information5.111 Principles of Chemical Science
MIT OpenCourseWare http://ocw.mit.edu 5.111 Principles of Chemical Science Fall 2008 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms. 26.1 5.111 Lecture
More information12. REDOX EQUILIBRIA
12. REDOX EQUILIBRIA The electrochemical series (reference table) 12.1. Redox reactions 12.2. Standard electrode potentials 12.3. Calculations involving electrochemical cells 12.4. Using Eʅ values to predict
More informationAP CHEMISTRY 2009 SCORING GUIDELINES (Form B)
AP CHEMISTRY 2009 SCORING GUIDELINES (Form B) Question 3 (10 points) 2 H 2 O 2 (aq) 2 H 2 O(l) + O 2 (g) The mass of an aqueous solution of H 2 O 2 is 6.951 g. The H 2 O 2 in the solution decomposes completely
More informationElectrochemistry. Chapter 18 Electrochemistry and Its Applications. Redox Reactions. Redox Reactions. Redox Reactions
John W. Moore Conrad L. Stanitski Peter C. Jurs http://academic.cengage.com/chemistry/moore Chapter 18 Electrochemistry and Its Applications Stephen C. Foster Mississippi State University Electrochemistry
More informationDiscovering Electrochemical Cells
Discovering Electrochemical Cells Part I Electrolytic Cells Many important industrial processes PGCC CHM 102 Cell Construction e e power conductive medium What chemical species would be present in a vessel
More informationChemistry 2014 Scoring Guidelines
AP Chemistry 2014 Scoring Guidelines 2014 The College Board. College Board, Advanced Placement Program, AP, AP Central, and the acorn logo are registered trademarks of the College Board. Visit the College
More informationRedox and Electrochemistry
Name: Thursday, May 08, 2008 Redox and Electrochemistry 1. A diagram of a chemical cell and an equation are shown below. When the switch is closed, electrons will flow from 1. the Pb(s) to the Cu(s) 2+
More informationGalvanic Cells. SCH4U7 Ms. Lorenowicz. Tuesday, December 6, 2011
Galvanic Cells SCH4U7 Ms. Lorenowicz 1 Electrochemistry Concepts 1.Redox reactions involve the transfer of electrons from one reactant to another 2.Electric current is a flow of electrons in a circuit
More informationMULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
Chemistry 1C-Dr. Larson Chapter 20 Review Questions MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) is reduced in the following reaction: Cr2O7
More informationCHAPTER 13: Electrochemistry and Cell Voltage
CHAPTER 13: Electrochemistry and Cell Voltage In this chapter: More about redox reactions Cells, standard states, voltages, half-cell potentials Relationship between G and voltage and electrical work Equilibrium
More informationName Electrochemical Cells Practice Exam Date:
Name Electrochemical Cells Practice Exam Date: 1. Which energy change occurs in an operating voltaic cell? 1) chemical to electrical 2) electrical to chemical 3) chemical to nuclear 4) nuclear to chemical
More informationSummer 2003 CHEMISTRY 115 EXAM 3(A)
Summer 2003 CHEMISTRY 115 EXAM 3(A) 1. In which of the following solutions would you expect AgCl to have the lowest solubility? A. 0.02 M BaCl 2 B. pure water C. 0.02 M NaCl D. 0.02 M KCl 2. Calculate
More informationBalancing Reaction Equations Oxidation State Reduction-oxidation Reactions
Balancing Reaction Equations Oxidation State Reduction-oxidation Reactions OCN 623 Chemical Oceanography Balanced chemical reactions are the math of chemistry They show the relationship between the reactants
More informationChapter 20. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
Chapter 20 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The gain of electrons by an element is called. A) oxidation B) reduction C) sublimation
More informationUseful charge on one mole of electrons: 9.64 x 10 4 coulombs/mol e - = F F is the Faraday constant
Electrochemistry II: Cell voltage and Gibbs Free energy Reading: Moore chapter 19, sections 15.6-15.12 Questions for Review and Thought: 36, 40, 42, 44, 50, 54, 60, 64, 70 Key Concepts and Skills: definition
More informationFinal Exam CHM 3410, Dr. Mebel, Fall 2005
Final Exam CHM 3410, Dr. Mebel, Fall 2005 1. At -31.2 C, pure propane and n-butane have vapor pressures of 1200 and 200 Torr, respectively. (a) Calculate the mole fraction of propane in the liquid mixture
More informationAP Chemistry 2009 Free-Response Questions Form B
AP Chemistry 009 Free-Response Questions Form B The College Board The College Board is a not-for-profit membership association whose mission is to connect students to college success and opportunity. Founded
More informationCELL POTENTIAL, E. Terms Used for Galvanic Cells. Uses of E o Values CELL POTENTIAL, E. Galvanic Cell. Organize halfreactions
Electrons move from anode to cathode in the wire. Anions & cations move thru the salt bridge. Terms Used for Galvanic Cells Galvanic Cell We can calculate the potential of a Galvanic cell using one of
More informationElectrochemistry. Pre-Lab Assignment. Purpose. Background. Experiment 12
Experiment 12 Electrochemistry Pre-Lab Assignment Before coming to lab: Read the lab thoroughly. Answer the pre-lab questions that appear at the end of this lab exercise. The questions should be answered
More informationDetermining Equivalent Weight by Copper Electrolysis
Purpose The purpose of this experiment is to determine the equivalent mass of copper based on change in the mass of a copper electrode and the volume of hydrogen gas generated during an electrolysis reaction.
More informationCHEM1909 2006-N-2 November 2006
CHEM1909 006-N- November 006 High-purity benzoic acid, C 6 H 5 COOH, (H comb = 37 kj mol 1 ) is used to calibrate a bomb calorimeter that has a 1.000 L capacity. A 1.000 g sample of C 6 H 5 COOH is placed
More informationOXIDATION REDUCTION. Section I. Cl 2 + 2e. 2. The oxidation number of group II A is always (+) 2.
OXIDATION REDUCTION Section I Example 1: Na Example 2: 2C1 Example 3: K + + e Na + + e Cl 2 + 2e K Example 4: C1 2 + 2e 2Cl 1. The oxidation number of group I A is always (+) 1. 2. The oxidation number
More informationAP Chemistry CHAPTER 20- Electrochemistry 20.1 Oxidation States
AP Chemistry CHAPTER 20- Electrochemistry 20.1 Oxidation States Chemical reactions in which the oxidation state of a substance changes are called oxidation-reduction reactions (redox reactions). Oxidation
More informationBoyle s law - For calculating changes in pressure or volume: P 1 V 1 = P 2 V 2. Charles law - For calculating temperature or volume changes: V 1 T 1
Common Equations Used in Chemistry Equation for density: d= m v Converting F to C: C = ( F - 32) x 5 9 Converting C to F: F = C x 9 5 + 32 Converting C to K: K = ( C + 273.15) n x molar mass of element
More informationAP Chemistry 2009 Free-Response Questions
AP Chemistry 009 Free-Response Questions The College Board The College Board is a not-for-profit membership association whose mission is to connect students to college success and opportunity. Founded
More informationChemistry B11 Chapter 4 Chemical reactions
Chemistry B11 Chapter 4 Chemical reactions Chemical reactions are classified into five groups: A + B AB Synthesis reactions (Combination) H + O H O AB A + B Decomposition reactions (Analysis) NaCl Na +Cl
More informationExperiment 9 Electrochemistry I Galvanic Cell
9-1 Experiment 9 Electrochemistry I Galvanic Cell Introduction: Chemical reactions involving the transfer of electrons from one reactant to another are called oxidation-reduction reactions or redox reactions.
More information10 Cl atoms. 10 H2O molecules. 8.3 mol HCN = 8.3 mol N atoms 1 mol HCN. 2 mol H atoms 2.63 mol CH2O = 5.26 mol H atoms 1 mol CH O
Chem 100 Mole conversions and stoichiometry worksheet 1. How many Ag atoms are in.4 mol Ag atoms? 6.0 10 Ag atoms 4.4 mol Ag atoms = 1.46 10 Ag atoms 1 mol Ag atoms. How many Br molecules are in 18. mol
More informationAP Chemistry 2012 Free-Response Questions
AP Chemistry 01 Free-Response Questions About the College Board The College Board is a mission-driven not-for-profit organization that connects students to college success and opportunity. Founded in 1900,
More informationPractical Examples of Galvanic Cells
56 Practical Examples of Galvanic Cells There are many practical examples of galvanic cells in use in our everyday lives. We are familiar with batteries of all types. One of the most common is the lead-acid
More information10. Calculate the mass percent nitrogen in (NH 4 ) 2 CO 3 (molar mass = 96.09 g/mol). a. 29.1 % c. 17.9 % e. 14.6 % b. 35.9 % d. 0.292 % f. 96.
Chem 171-2-3: Final Exam Review Multiple Choice Problems 1. What is the molar mass of barium perchlorate, Ba(ClO 4 ) 2? a. 189.90 g/mol c. 272.24 g/mol e. 336.20 g/mol b. 240.24 g/mol d. 304.24 g/mol f.
More informationChapter 8 - Chemical Equations and Reactions
Chapter 8 - Chemical Equations and Reactions 8-1 Describing Chemical Reactions I. Introduction A. Reactants 1. Original substances entering into a chemical rxn B. Products 1. The resulting substances from
More informationAP Chemistry 2008 Free-Response Questions
AP Chemistry 008 Free-Response Questions The College Board: Connecting Students to College Success The College Board is a not-for-profit membership association whose mission is to connect students to college
More informationCHEM 105 HOUR EXAM III 28-OCT-99. = -163 kj/mole determine H f 0 for Ni(CO) 4 (g) = -260 kj/mole determine H f 0 for Cr(CO) 6 (g)
CHEM 15 HOUR EXAM III 28-OCT-99 NAME (please print) 1. a. given: Ni (s) + 4 CO (g) = Ni(CO) 4 (g) H Rxn = -163 k/mole determine H f for Ni(CO) 4 (g) b. given: Cr (s) + 6 CO (g) = Cr(CO) 6 (g) H Rxn = -26
More informationStandard Free Energies of Formation at 298 K. Average Bond Dissociation Energies at 298 K
1 Thermodynamics There always seems to be at least one free response question that involves thermodynamics. These types of question also show up in the multiple choice questions. G, S, and H. Know what
More informationChem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses
Chem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses B. Calculations of moles C. Calculations of number of atoms from moles/molar masses 1. Avagadro
More information4. Using the data from Handout 5, what is the standard enthalpy of formation of BaO (s)? What does this mean?
HOMEWORK 3A 1. In each of the following pairs, tell which has the higher entropy. (a) One mole of liquid water or one mole of water vapor (b) One mole of dry ice or one mole of carbon dioxide at 1 atm
More informationInstructions Answer all questions in the spaces provided. Do all rough work in this book. Cross through any work you do not want to be marked.
GCSE CHEMISTRY Higher Tier Chemistry 1H H Specimen 2018 Time allowed: 1 hour 45 minutes Materials For this paper you must have: a ruler a calculator the periodic table (enclosed). Instructions Answer all
More informationChapter 11. Electrochemistry Oxidation and Reduction Reactions. Oxidation-Reduction Reactions. Oxidation-Reduction Reactions
Oxidation-Reduction Reactions Chapter 11 Electrochemistry Oxidation and Reduction Reactions An oxidation and reduction reaction occurs in both aqueous solutions and in reactions where substances are burned
More informationINTI COLLEGE MALAYSIA A? LEVEL PROGRAMME CHM 111: CHEMISTRY MOCK EXAMINATION: DECEMBER 2000 SESSION. 37 74 20 40 60 80 m/e
CHM111(M)/Page 1 of 5 INTI COLLEGE MALAYSIA A? LEVEL PROGRAMME CHM 111: CHEMISTRY MOCK EXAMINATION: DECEMBER 2000 SESSION SECTION A Answer ALL EIGHT questions. (52 marks) 1. The following is the mass spectrum
More informationExam 4 Practice Problems false false
Exam 4 Practice Problems 1 1. Which of the following statements is false? a. Condensed states have much higher densities than gases. b. Molecules are very far apart in gases and closer together in liquids
More informationAP Chemistry 2009 Scoring Guidelines
AP Chemistry 2009 Scoring Guidelines The College Board The College Board is a not-for-profit membership association whose mission is to connect students to college success and opportunity. Founded in 1900,
More informationELECTROCHEMICAL CELLS
1 ELECTROCHEMICAL CELLS Allessandra Volta (1745-1827) invented the electric cell in 1800 A single cell is also called a voltaic cell, galvanic cell or electrochemical cell. Volta joined several cells together
More information(b) As the mass of the Sn electrode decreases, where does the mass go?
A student is given a standard galvanic cell, represented above, that has a Cu electrode and a Sn electrode. As current flows through the cell, the student determines that the Cu electrode increases in
More informationPart B 2. Allow a total of 15 credits for this part. The student must answer all questions in this part.
Part B 2 Allow a total of 15 credits for this part. The student must answer all questions in this part. 51 [1] Allow 1 credit for 3 Mg(s) N 2 (g) Mg 3 N 2 (s). Allow credit even if the coefficient 1 is
More informationCLASS TEST GRADE 11. PHYSICAL SCIENCES: CHEMISTRY Test 6: Chemical change
CLASS TEST GRADE PHYSICAL SCIENCES: CHEMISTRY Test 6: Chemical change MARKS: 45 TIME: hour INSTRUCTIONS AND INFORMATION. Answer ALL the questions. 2. You may use non-programmable calculators. 3. You may
More informationQuestion Bank Electrolysis
Question Bank Electrolysis 1. (a) What do you understand by the terms (i) electrolytes (ii) non-electrolytes? (b) Arrange electrolytes and non-electrolytes from the following substances (i) sugar solution
More informationAnswers and Solutions to Text Problems
Chapter 7 Answers and Solutions 7 Answers and Solutions to Text Problems 7.1 A mole is the amount of a substance that contains 6.02 x 10 23 items. For example, one mole of water contains 6.02 10 23 molecules
More informationChapter 1. Introduction of Electrochemical Concepts
Chapter 1. Introduction of Electrochemical Concepts Electrochemistry concerned with the interrelation of electrical and chemical effects. Reactions involving the reactant the electron. Chemical changes
More informationName Class Date. In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question.
Assessment Chapter Test A Chapter: States of Matter In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question. 1. The kinetic-molecular
More informationChapter 18 Homework Answers
Chapter 18 Homework Answers 18.22. 18.24. 18.26. a. Since G RT lnk, as long as the temperature remains constant, the value of G also remains constant. b. In this case, G G + RT lnq. Since the reaction
More informationAP Chemistry 2011 Free-Response Questions
AP Chemistry 011 Free-Response Questions About the College Board The College Board is a mission-driven not-for-profit organization that connects students to college success and opportunity. Founded in
More informationneutrons are present?
AP Chem Summer Assignment Worksheet #1 Atomic Structure 1. a) For the ion 39 K +, state how many electrons, how many protons, and how many 19 neutrons are present? b) Which of these particles has the smallest
More informationBuilding Electrochemical Cells
Cautions Heavy metals, such as lead, and solutions of heavy metals may be toxic and an irritant. Purpose To determine the cell potential (E cell ) for various voltaic cells and compare the data with the
More information= 1.038 atm. 760 mm Hg. = 0.989 atm. d. 767 torr = 767 mm Hg. = 1.01 atm
Chapter 13 Gases 1. Solids and liquids have essentially fixed volumes and are not able to be compressed easily. Gases have volumes that depend on their conditions, and can be compressed or expanded by
More informationFinal. Mark Scheme. Chemistry CHEM5. (Specification 2420) Unit 5: Energetics, Redox and Inorganic Chemistry
Version.2 General Certificate of Education (A-level) January 202 Chemistry CHEM5 (Specification 2420) Unit 5: Energetics, Redox and Inorganic Chemistry Final Mark Scheme Mark schemes are prepared by the
More informationThe Mole. Chapter 10. Dimensional Analysis. The Mole. How much mass is in one atom of carbon-12? Molar Mass of Atoms 3/1/2015
The Mole Chapter 10 1 Objectives Use the mole and molar mass to make conversions among moles, mass, and number of particles Determine the percent composition of the components of a compound Calculate empirical
More informationChem 115 POGIL Worksheet - Week 4 Moles & Stoichiometry Answers
Key Questions & Exercises Chem 115 POGIL Worksheet - Week 4 Moles & Stoichiometry Answers 1. The atomic weight of carbon is 12.0107 u, so a mole of carbon has a mass of 12.0107 g. Why doesn t a mole of
More informationChemistry 110 Lecture Unit 5 Chapter 11-GASES
Chemistry 110 Lecture Unit 5 Chapter 11-GASES I. PROPERITIES OF GASES A. Gases have an indefinite shape. B. Gases have a low density C. Gases are very compressible D. Gases exert pressure equally in all
More informationCandidate Style Answer
Candidate Style Answer Chemistry A Unit F321 Atoms, Bonds and Groups High banded response This Support Material booklet is designed to accompany the OCR GCE Chemistry A Specimen Paper F321 for teaching
More informationIB Chemistry. DP Chemistry Review
DP Chemistry Review Topic 1: Quantitative chemistry 1.1 The mole concept and Avogadro s constant Assessment statement Apply the mole concept to substances. Determine the number of particles and the amount
More informationChapter 3 Mass Relationships in Chemical Reactions
Chapter 3 Mass Relationships in Chemical Reactions Student: 1. An atom of bromine has a mass about four times greater than that of an atom of neon. Which choice makes the correct comparison of the relative
More informationCHAPTER 10: INTERMOLECULAR FORCES: THE UNIQUENESS OF WATER Problems: 10.2, 10.6,10.15-10.33, 10.35-10.40, 10.56-10.60, 10.101-10.
CHAPTER 10: INTERMOLECULAR FORCES: THE UNIQUENESS OF WATER Problems: 10.2, 10.6,10.15-10.33, 10.35-10.40, 10.56-10.60, 10.101-10.102 10.1 INTERACTIONS BETWEEN IONS Ion-ion Interactions and Lattice Energy
More informationCHEM 1211K Test IV. MULTIPLE CHOICE (3 points each)
CEM 1211K Test IV MULTIPLE COICE (3 points each) 1) ow many single covalent bonds must a silicon atom form to have a complete octet in its valence shell? A) 4 B) 3 C) 1 D) 2 E) 0 2) What is the maximum
More informationChapter 12: Oxidation and Reduction.
207 Oxidation- reduction (redox) reactions Chapter 12: Oxidation and Reduction. At different times, oxidation and reduction (redox) have had different, but complimentary, definitions. Compare the following
More informationElectronegativity and Polarity
and Polarity N Goalby Chemrevise.org Definition: is the relative tendency of an atom in a molecule to attract electrons in a covalent bond to itself. is measured on the Pauling scale (ranges from 0 to
More informationAPPENDIX B: EXERCISES
BUILDING CHEMISTRY LABORATORY SESSIONS APPENDIX B: EXERCISES Molecular mass, the mole, and mass percent Relative atomic and molecular mass Relative atomic mass (A r ) is a constant that expresses the ratio
More informationAP* Chemistry ELECTROCHEMISTRY
Terms to Know: AP* Chemistry ELECTROCHEMISTRY the study of the interchange of chemical and electrical energy OIL RIG oxidation is loss, reduction is gain (of electrons) Oxidation the loss of electrons,
More informationAP Chemistry 2006 Free-Response Questions
AP Chemistry 006 Free-Response Questions The College Board: Connecting Students to College Success The College Board is a not-for-profit membership association whose mission is to connect students to college
More informationFinal Exam Review. I normalize your final exam score out of 70 to a score out of 150. This score out of 150 is included in your final course total.
Final Exam Review Information Your ACS standardized final exam is a comprehensive, 70 question multiple choice (a d) test featuring material from BOTH the CHM 101 and 102 syllabi. Questions are graded
More informationChapter 17. The best buffer choice for ph 7 is NaH 2 PO 4 /Na 2 HPO 4. 19)
Chapter 17 2) a) HCl and CH 3 COOH are both acids. A buffer must have an acid/base conjugate pair. b) NaH 2 PO 4 and Na 2 HPO 4 are an acid/base conjugate pair. They will make an excellent buffer. c) H
More informationThe first law: transformation of energy into heat and work. Chemical reactions can be used to provide heat and for doing work.
The first law: transformation of energy into heat and work Chemical reactions can be used to provide heat and for doing work. Compare fuel value of different compounds. What drives these reactions to proceed
More informationSolution a homogeneous mixture = A solvent + solute(s) Aqueous solution water is the solvent
Solution a homogeneous mixture = A solvent + solute(s) Aqueous solution water is the solvent Water a polar solvent: dissolves most ionic compounds as well as many molecular compounds Aqueous solution:
More informationAP CHEMISTRY 2007 SCORING GUIDELINES. Question 2
AP CHEMISTRY 2007 SCORING GUIDELINES Question 2 N 2 (g) + 3 F 2 (g) 2 NF 3 (g) ΔH 298 = 264 kj mol 1 ; ΔS 298 = 278 J K 1 mol 1 The following questions relate to the synthesis reaction represented by the
More informationCHAPTER 3 Calculations with Chemical Formulas and Equations. atoms in a FORMULA UNIT
CHAPTER 3 Calculations with Chemical Formulas and Equations MOLECULAR WEIGHT (M. W.) Sum of the Atomic Weights of all atoms in a MOLECULE of a substance. FORMULA WEIGHT (F. W.) Sum of the atomic Weights
More informationCHEMISTRY II FINAL EXAM REVIEW
Name Period CHEMISTRY II FINAL EXAM REVIEW Final Exam: approximately 75 multiple choice questions Ch 12: Stoichiometry Ch 5 & 6: Electron Configurations & Periodic Properties Ch 7 & 8: Bonding Ch 14: Gas
More informationCHEMISTRY. Matter and Change. Section 13.1 Section 13.2 Section 13.3. The Gas Laws The Ideal Gas Law Gas Stoichiometry
CHEMISTRY Matter and Change 13 Table Of Contents Chapter 13: Gases Section 13.1 Section 13.2 Section 13.3 The Gas Laws The Ideal Gas Law Gas Stoichiometry State the relationships among pressure, temperature,
More informationPV (0.775 atm)(0.0854 L) n = = = 0.00264 mol RT -1-1
catalyst 2 5 g ¾¾¾¾ 2 4 g 2 g DH298 = rxn DS298 C H OH( ) C H ( ) + H O( ) 45.5 kj/mol ; = 126 J/(K mol ) ethanol ethene water rxn 1 atm 760 torr PV (0.775 atm)(0.0854 L) n = = = 0.00264 mol RT -1-1 (0.08206
More informationPercent Composition and Molecular Formula Worksheet
Percent Composition and Molecular Formula Worksheet 1. What s the empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen, and 29.0% 2. If the molar mass of the compound in problem 1 is
More information