Chem 75 Winter, 2017 Practice Exam 3
|
|
- Alexandra Nelson
- 6 years ago
- Views:
Transcription
1 1. The Handbook of Chemistry and Physics says that PbBr 2 is soluble in water to the tune of g per kg of water at 25 C. The molar mass of PbBr 2 is 367 g mol 1. (a) What is the ionic strength of an aqueous solution saturated with PbBr 2? (b) What does the Debye-Hückel Limiting Law predict γ ± to be for this solution? (c) The Handbook also says that K = for PbBr 2 (s) Pb 2+ (aq) + 2 Br (aq). What does this number predict γ ± to be? 2. Co and Ni have very similar standard reduction potentials at 298 K: Ni 2+ (aq) + 2e Ni(s) E o red = V Co 2+ (aq) + 2e Co(s) E o red = V (a) What is the equilibrium constant for Ni 2+ + Co Ni + Co 2+? (b) For the cell Co(s) Co 2+ (aq, a = 1) Ni 2+ (aq, a = 0.01) Ni(s) with ion activities as shown, what is the spontaneous net reaction that would occur if current was allowed to flow between the metal electrodes? (The notation in the cell schematic above represents a salt bridge that connects the two solutions.) 3. A common electrochemical cell used for halide ion determinations consists of a Ag(s) Ag + (aq) half cell connected through a salt bridge to a half cell called a calomel electrode. The calomel half cell uses solid mercury(i) chloride (Hg 2 Cl 2 (s), which is calomel) and a saturated KCl solution in contact with a small amount of elemental mercury, Hg(l), which is in contact with a chemically inert wire to which electrical contact is made. The half reactions and their reduction potentials at 298 K for this cell are Ag + (aq) + e Ag(s) E o red = V 1 2 Hg 2 Cl 2(s) + e Hg(l) + Cl (aq, saturated KCl) E red = V Note that the calomel reduction potential is listed as E red instead of E o red because the potential, V, is based on a saturated solution of Cl (aq) in which [Cl ] does not change. This means the cell emf will depend only on [Ag + ] and these two reduction potentials. The net cell reaction is Hg(l) + Cl (aq) + Ag + (aq) 0.5 Hg 2 Cl 2 (s) + Ag(s). (a) If such a cell exhibits an emf of V, what must [Ag + ] be? (b) The Ag Ag + half cell normally contains Ag + (aq) and an inert anion, typically NO 3 (aq). If a solution containing Cl (aq) is added to this half cell, insoluble AgCl(s) precipitates. What is the cell emf if enough Cl (aq) is added to establish [Cl ] = 0.01 mol kg 1, given also that the solubility product for AgCl is K sp = (You may approximate all activity coefficients for ions to be 1, just to simplify the problem a bit.) 4. BaSO 4 (s) is not very soluble in water. Let s look into that fact here. (a) Calculate the solubility product equilibrium constant K sp for BaSO 4 from the following molar free energies of formation, expressed for your computational convenience as ΔG f o /RT at 298 K.
2 BaSO 4 (s) Ba 2+ 2 (aq) SO 4 (aq) ΔG o f /RT (b) Now calculate K sp from another line of reasoning. Experimentally, one finds mg (or mol) of BaSO 4 dissolves in 0.1 L of water at 298 K. What K sp does this fact predict, assuming that all activity coefficients are 1? (c) Your answer in part (b) should be close to that in (a), but a bit larger. Why are the answers different, and why is the part (b) answer larger? 5. Several areas of contemporary research rely on a technique know as time-of-flight mass spectrometry. This device lets a brief pulse of a gas sample into a vacuum chamber, into which the gas molecules fly on straight-line paths without collision until they reach a detector that (often via electron bombardment) turns them into gaseous cations that can be detected as an electrical current. Suppose a puff of a mixture of He (mass 4 g mol 1 ) and Ar (mass 40 g mol 1 ) is injected into such a device via a small hole equipped with a fast-acting shutter. Suppose as well that the gas starts at 300 K. If the detector is m away from the hole, at what times after the shutter opens will the He and Ar detector signals be largest? (Assume the shutter opens and closes much more quickly than the times it takes either gas to reach the detector.) 6. Solid antimony is placed in an evacuated cell which is heated to 763 K. Antimony vapor is allowed to effuse from this cell into a vacuum chamber through a pinhole of area cm 2. The vapor pressure inside the cell is atm. The cell is observed to change mass at the rate g s 1. Is the principle species in antimony vapor Sb atoms, Sb 2, Sb 3, or what? 7. The measured diffusion coefficient for N 2 gas at 1 atm and 80 C is m 2 s 1, and at 1 atm and 78.5 C, D = m 2 s 1. (a) If you had only the 80 C value and our hard-sphere theory of transport phenomena, what would you predict the 78.5 C value to be? (b) What would you predict the N 2 viscosity coefficient, η, to be at 80 C and 1 atm? (c) Now consider the diffusion constant of gaseous ethylene, C 2 H 4. Compared to the N 2 value at some T and P, would the ethylene value be larger or smaller at that same T and P, and why? 8. Robert Boyle did the following experiment in He observed the damping time of a pendulum in a vessel at two different air pressures. If a pendulum takes 15 min to come to rest swinging in a gas at 1 atm, will it come to rest faster or slower in a gas at 0.1 atm, and why? 9. The K/Na phase diagram is shown below. Key temperatures are shown above the diagram lines, and the composition is expressed in atomic percent (which is mole fraction times 100) with pure K on the left and pure Na on the right.
3 (a) Note the short vertical line at 66.6% Na that ends at 6.92 C. It represents a stoichiometric compound Na 2 K. Unlike most compounds, though, Na 2 K(s) does not melt at one sharp temperature. What does the phase diagram say happens to Na 2 K(s) at 6.92 C? (b) A liquid Na/K solution at the eutectic composition is cooled to C. What happens at this temperature, i.e., what phases are in equilibrium?
4 Solutions 1. The Handbook of Chemistry and Physics says that PbBr 2 is soluble in water to the tune of g per kg of water at 25 C. The molar mass of PbBr 2 is 367 g mol 1. (a) What is the ionic strength of an aqueous solution saturated with PbBr 2? (b) What does the Debye-Hückel Limiting Law predict γ ± to be for this solution? (c) The Handbook also says that K = for PbBr 2 (s) Pb 2+ (aq) + 2 Br (aq). What does this number predict γ ± to be? (a) At saturation, we can find the analytic molality of dissolved PbBr 2 and thus of the dissolved ions quite easily: g kg 1 m PbBr2 = 367 g mol 1 = mol kg 1 = m + m = 2m + = mol kg 1 and from this, we find the ionic strength, I: I = mol kg 1 + ( 1) mol kg 1 = mol kg 1 (b) The D-H limiting law next tells us (z + = 2, z = 1) γ ± = exp z + z kg 1/2 mol 1/2 I 1/2 = (c) If K sp = , then we can write 2 K = a Pb 2+a Br = γ ± m 3 ± = γ 3 ± m+ m 2 or γ ± = K m + m 2 1/3 = Co and Ni have very similar standard reduction potentials at 298 K: Ni 2+ (aq) + 2e Ni(s) E o red = V Co 2+ (aq) + 2e Co(s) E o red = V (a) What is the equilibrium constant for Ni 2+ + Co Ni + Co 2+? (b) For the cell Co(s) Co 2+ (aq, a = 1) Ni 2+ (aq, a = 0.01) Ni(s) with ion activities as shown, what is the spontaneous net reaction that would occur if current was allowed to flow between the metal electrodes? (The notation in the cell schematic above represents a salt bridge that connects the two solutions.) (a) We first find E o from the standard reduction potentials (based on the net reaction as written with Ni 2+ reduced and Co oxidized): E o = E o red(reduction 1/2-rxn) Ered o (oxidation 1/2-rxn) = V ( V) = V and from this, we calculate K, the equilibrium constant, noting that the net reaction is a two-electron redox reaction: n = 2 (and recalling that RT/F = mv at 298 K) K = e ΔG R o /RT = e + nfeo /RT = e 2(0.027 V)/( V) = 8.2 (b) The full Nernst equation here is
5 E = E o RT nf ln a Co 2+ a Ni 2+ = V V ln = V and, because this value is negative, we see that the spontaneous process in this cell would be the reverse of the original net reaction, i.e., Ni + Co 2+ Ni 2+ + Co. 3. A common electrochemical cell used for halide ion determinations consists of a Ag(s) Ag + (aq) half cell connected through a salt bridge to a half cell called a calomel electrode. The calomel half cell uses solid mercury(i) chloride (Hg 2 Cl 2 (s), which is calomel) and a saturated KCl solution in contact with a small amount of elemental mercury, Hg(l), which is in contact with a chemically inert wire to which electrical contact is made. The half reactions and their reduction potentials at 298 K for this cell are Ag + (aq) + e Ag(s) E o red = V 1 2 Hg 2 Cl 2(s) + e Hg(l) + Cl (aq, saturated KCl) E red = V Note that the calomel reduction potential is listed as E red instead of E o red because the potential, V, is based on a saturated solution of Cl (aq) in which [Cl ] does not change. This means the cell emf will depend only on [Ag + ] and these two reduction potentials. The net cell reaction is Hg(l) + Cl (aq) + Ag + (aq) 0.5 Hg 2 Cl 2 (s) + Ag(s). (a) If such a cell exhibits an emf of V, what must [Ag + ] be? (b) The Ag Ag + half cell normally contains Ag + (aq) and an inert anion, typically NO 3 (aq). If a solution containing Cl (aq) is added to this half cell, insoluble AgCl(s) precipitates. What is the cell emf if enough Cl (aq) is added to establish [Cl ] = 0.01 mol kg 1, given also that the solubility product for AgCl is K sp = (You may approximate all activity coefficients for ions to be 1, just to simplify the problem a bit.) (a) The Nernst equation here is (with E o based on the net reaction in which Ag + is reduced and Hg is oxidized) E = E o RT nf ln 1 a Ag + = (0.799 V V) V 1 ln 1 a Ag + = V and we solve for the silver activity: a Ag + = or [Ag + ] 1.02 mm with [Ag + ] in mm units which is an appropriate approximation because the activity is so small, making the activity coefficient close to 1 and the molality concentration approximately equal to a molarity concentration. (b) This is easy. If [Cl ] = 0.01 mol kg 1, then [Ag + ] = K sp /[Cl ] = mol kg 1 so that
6 E = E o RT nf ln 1 a Ag + = V V ln 1 = V BaSO 4 (s) is not very soluble in water. Let s look into that fact here. (a) Calculate the solubility product equilibrium constant K sp for BaSO 4 from the following molar free energies of formation, expressed for your computational o convenience as ΔG f /RT at 298 K. BaSO 4 (s) Ba 2+ 2 (aq) SO 4 (aq) ΔG o f /RT (b) Now calculate K sp from another line of reasoning. Experimentally, one finds mg (or mol) of BaSO 4 dissolves in 0.1 L of water at 298 K. What K sp does this fact predict, assuming that all activity coefficients are 1? (c) Your answer in part (b) should be close to that in (a), but a bit larger. Why are the answers different, and why is the part (b) answer larger? (a) The K sp net reaction is BaSO 4 (s) Ba2+ (aq) + SO 4 2 (aq) so that ΔGR o is given by so that ΔG o R RT = ΔG f o (Ba 2+ ) + ΔG f o 2 (SO 4 ) ΔG f o (BaSO 4 ) = RT RT RT K sp = e ΔG R o /RT = e = (b) Here, we turn the solubility information into ion concentrations at saturation: [Ba 2+ ] = [SO 4 2 ] = mol 0.1 L = M and write K sp = [Ba 2+ ][SO 4 2 ] = ( ) 2 = The reason this value is a bit larger than the value based on free energy of formation values is easy to see: we have assumed activity coefficients of 1, but in fact they will be a bit less that 1 (the Debye-Hückel limiting law predicts γ ± = 0.970) so that the real activities will be a bit less than the molar concentrations, dropping K sp a bit. In fact, with this γ ± value, we change K sp to ( )(0.970) 2 = , spot on the value from part (a)! 5. Several areas of contemporary research rely on a technique know as time-of-flight mass spectrometry. This device lets a brief pulse of a gas sample into a vacuum chamber, into which the gas molecules fly on straight-line paths without collision until they reach a detector that (often via electron bombardment) turns them into gaseous cations that can be detected as an electrical current.
7 Suppose a puff of a mixture of He (mass 4 g mol 1 ) and Ar (mass 40 g mol 1 ) is injected into such a device via a small hole equipped with a fast-acting shutter. Suppose as well that the gas starts at 300 K. If the detector is m away from the hole, at what times after the shutter opens will the He and Ar detector signals be largest? (Assume the shutter opens and closes much more quickly than the times it takes either gas to reach the detector.) The signal will be largest when the greatest number of molecules happen to fly by the detector. These molecules will be moving at the most probable speed, v mp so that v mp = 2k B T m = ( m s 1 ) T/K M/g mol 1 = 1116 m s 1 for He m s 1 for Ar Their time to travel m will be t = m v mp = 112 μs for He 354 μs for Ar While microsecond times seem like they would be no time at all, it is easy to record events happening on this time scale (and even briefer scales) with modern electronics. 6. Solid antimony is placed in an evacuated cell which is heated to 763 K. Antimony vapor is allowed to effuse from this cell into a vacuum chamber through a pinhole of area cm 2 in a very thin cell wall. The vapor pressure inside the cell is atm. The cell is observed to change mass at the rate g s 1. Is the principle species in antimony vapor Sb atoms, Sb 2, Sb 3, or what? We have a cell at temperature T and (unknown) vapor pressure P which has a small circular hole of radius r through which mass Δm is lost in time t. The rate of loss of molecules is given by dn/dt = Z w A where A = πr 2, the hole area, and Z w is the rate of collisions with the wall: Z w = P 2πmk B T 1/2 Thus, the total number of molecules lost in time t is just ΔN = Z w At, and thus the mass loss is just this number times the mass per molecule: Δm = mpat 2πmk B T 1/2 which can be solved for P (but we know P here) or rearranged to give the mass loss rate: Δm = m 1/2 PA t 2πk B T Here, we know the rate and seek the mass of effusing particles, m. Converting our input data into base SI quantities gives us
8 m = Δm t 2πk B T 1/2 PA 2 = kg s 1 2πk B (763 K) 1/ Pa m 2 = kg = 4 (the mass of one Sb atom, which is kg) Thus, Sb 4 is the main gas-phase form of Sb at this temperature. (And by the way, the hard part of these experiments is finding a way to accurately measure μg mass changes in a metal cell at 700+ K while also measuring the gas pressure in the cell, all suspended in an ultra-high vacuum chamber!) 7. The measured diffusion coefficient for N 2 gas at 1 atm and 80 C is m 2 s 1, and at 1 atm and 78.5 C, D = m 2 s 1. (a) If you had only the 80 C value and our hard-sphere theory of transport phenomena, what would you predict the 78.5 C value to be? (b) What would you predict the N 2 viscosity coefficient, η, to be at 80 C and 1 atm? (c) Now consider the diffusion constant of gaseous ethylene, C 2 H 4. Compared to the N 2 value at some T and P, would the ethylene value be larger or smaller at that same T and P, and why? (a) Our theory says that, at constant P, D varies with T as T 3/2. Thus, we can write D( 78.5 C = K) = D(80. C = K) /2 = m s 1 (b) If we compare our expressions for D and η, we see that ρd = η where ρ is the gas mass density, mn/v: 2 D = v λ 3 η = v λ 3 mn so η = D mn V V = Dρ We can also express the gas mass density in more familiar terms with M the gas molar mass (in kg mol 1 units): ρ = mn V = mnp nrt = MP RT which, for N 2 at 1 atm and 80 C, yields ρ = kg m 3 and thus we predict η = Dρ = Pa s. The literature value is Pa s. Not bad! (c) Our expression for D has two simple factors: the mean speed and the mean free path. The mass of ethylene is pretty much identical to that of N 2 (28.05 g mol 1 for C 2 H 4 versus g mol 1 for N 2 ), which gives them equal mean speeds. But C 2 H 4 is bigger (has a larger collision cross-section) than N 2, making its mean free path smaller than that of N 2. Thus D(N 2 ) > D(C 2 H 4 ). 8. Robert Boyle did the following experiment in He observed the damping time of a pendulum in a vessel at two different air pressures. If a pendulum takes 15 min
9 to come to rest swinging in a gas at 1 atm, will it come to rest faster or slower in a gas at 0.1 atm, and why? This question boils down (no pun intended...) to the question of how viscosity varies with pressure for gases around 1 atm pressure. Our viscosity theory shows that η is independent of P: as the gas density goes up with increasing pressure at constant T, the mean free path goes down at the same rate. More molecules are available to transport momentum at higher pressures, but they carry it over shorter distances. The two effects cancel exactly. Mr. Boyle s pendulum would take the same 15 minutes to come to rest at 0.1 atm as at 1 atm. Gaseous thermal conductivity is independent of pressure (unless the pressure is very low) for the same reason. 9. The K/Na phase diagram is shown below. Key temperatures are shown above the diagram lines, and the composition is expressed in atomic percent (which is mole fraction times 100) with pure K on the left and pure Na on the right. liquid + liquid + Na 2 K + liq. Na 2 K + Na 2 K + (a) Note the short vertical line at 66.6% Na that ends at 6.92 C. It represents a stoichiometric compound Na 2 K. Unlike most compounds, though, Na 2 K(s) does not melt at one sharp temperature. What does the phase diagram say happens to Na 2 K(s) at 6.92 C?
10 The diagram above has had the various areas labeled to show what phase or phases each represents. On the K side, the area labeled α is a one-phase homogeneous solid solution that is mostly K, and on the Na side, the area labeled β is a similar one-phase solid solution that is mostly Na. At 6.92 C, Na 2 K(s) melts into a liquid solution and a solid β phase. Much like a eutectic point, we have three phases in equilibrium: solid Na 2 K, solid β, and the liquid solution. The temperature is stuck at 6.92 C until all the solid Na 2 K is gone and only liquid + β appears. (b) A liquid Na/K solution at the eutectic composition is cooled to C. What happens at this temperature, i.e., what phases are in equilibrium? Here, the eutectic liquid freezes into a mixture of α solid and Na 2 K(s). The temperature is stuck at C until all the liquid has solidified into this mixture of α solid and Na 2 K(s).
8. ELECTROCHEMICAL CELLS. n Electrode Reactions and Electrode Potentials a. H 2 2H + + 2e. Cl 2 + 2e 2Cl. H 2 + Cl 2 2H + + 2Cl ; z = 2
8. ELECTROCHEMICAL CELLS n Electrode Reactions and Electrode Potentials 8.1. a. H H + + e Cl + e Cl H + Cl H + + Cl ; z = E = E RT F ln ( a H +a Cl ) b. Hg(l)+ Cl Hg Cl + e H + + e H Hg + H + + Cl Hg Cl
More informationChapter 18 Electrochemistry. Electrochemical Cells
Chapter 18 Electrochemistry Chapter 18 1 Electrochemical Cells Electrochemical Cells are of two basic types: Galvanic Cells a spontaneous chemical reaction generates an electric current Electrolytic Cells
More informationCHEM 10123/10125, Exam 3
CHEM 10123/10125, Exam 3 April 4, 2012 (50 minutes) Name (please print) Please box your answers, and remember that significant figures, phases (for chemical equations), and units do count! 1. (18 points)
More information3. Which of the following compounds is soluble? The solubility rules are listed on page 8.
1. Classify the following reaction. Sb 2 O 3 + 3 Fe 2 Sb + 3 FeO a) Combination reaction b) Decomposition reaction c) Neutralization reaction d) Single-replacement reaction e) Double-replacement reaction
More informationChemistry 122 Wrap-Up Review Kundell
Chapter 11 Chemistry 122 Wrap-Up Review Kundell 1. The enthalpy (heat) of vaporization for ethanol (C 2 H 5 OH) is 43.3 kj/mol. How much heat, in kilojoules, is required to vaporize 115 g of ethanol at
More informationElectrochemistry. Chapter 18. Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Electrochemistry Chapter 18 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Electrochemical processes are oxidation-reduction reactions in which: the energy
More informationSolutions. Heterogenous Mixture (Not a Solution) Ice Water (w/ Ice Cubes) Smog Oil and Water
Solutions Unit 6 1 Solutions Homogenous Mixture (Solution) two or more substances mixed together to have a uniform composition, its components are not distinguishable from one another Heterogenous Mixture
More informationCHM 213 (INORGANIC CHEMISTRY): Applications of Standard Reduction Potentials. Compiled by. Dr. A.O. Oladebeye
CHM 213 (INORGANIC CHEMISTRY): Applications of Standard Reduction Potentials Compiled by Dr. A.O. Oladebeye Department of Chemistry University of Medical Sciences, Ondo, Nigeria Electrochemical Cell Electrochemical
More informationELECTROCHEMISTRY. these are systems involving oxidation or reduction there are several types METALS IN CONTACT WITH SOLUTIONS OF THEIR IONS
Electrochemistry 1 ELECTROCHEMISTRY REDOX Reduction gain of electrons Cu 2+ (aq) + 2e > Cu(s) Oxidation removal of electrons Zn(s) > Zn 2+ (aq) + 2e HALF CELLS these are systems involving oxidation or
More informationChapter 18 problems (with solutions)
Chapter 18 problems (with solutions) 1) Assign oxidation numbers for the following species (for review see section 9.4) a) H2SO3 H = +1 S = +4 O = -2 b) Ca(ClO3)2 Ca = +2 Cl = +5 O = -2 c) C2H4 C = -2
More informationCh 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 informationCHEMISTRY 110 EXAM 3 Nov. 11, 2013 ORM A!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" 1. The cylinder shown below is filled with enough N 2 gas at 25 o C to reach a
More informationName (Print) Section # or TA. 1. You may use a crib sheet which you prepared in your own handwriting. This may be
Name (Print) Section # or TA 1. You may use a crib sheet which you prepared in your own handwriting. This may be one 8-1/2 by 11 inch sheet of paper with handwriting only on one side. 2. You may use a
More informationChapter 5 Gases and the Kinetic-Molecular Theory
Chapter 5 Gases and the Kinetic-Molecular Theory Name (Formula) Methane (CH 4 ) Ammonia (NH 3 ) Chlorine (Cl 2 ) Oxygen (O 2 ) Ethylene (C 2 H 4 ) Origin and Use natural deposits; domestic fuel from N
More informationSoluble: A solute that dissolves in a specific solvent. Insoluble: A solute that will not dissolve in a specific solvent. "Like Dissolves Like"
Solutions Homogeneous Mixtures Solutions: Mixtures that contain two or more substances called the solute and the solvent where the solute dissolves in the solvent so the solute and solvent are not distinguishable
More informationWhy study gases? A Gas 10/17/2017. An understanding of real world phenomena. An understanding of how science works.
Kinetic Theory and the Behavior of Ideal & Real Gases Why study gases? n understanding of real world phenomena. n understanding of how science works. Gas Uniformly fills any container. Mixes completely
More informationAP Chapter 14: Chemical Equilibrium & Ksp
AP Chapter 14: Chemical Equilibrium & Ksp Warm-Ups (Show your work for credit) Name Date 1. Date 2. Date 3. Date 4. Date 5. Date 6. Date 7. Date 8. AP Chapter 14: Chemical Equilibrium & Ksp 2 Warm-Ups
More informationChapter 19 Chemical Thermodynamics
Chapter 19. Chemical Thermodynamics Sample Exercise 19.2 (p. 819) Elemental mercury is a silver liquid at room temperature. Its normal freezing point is -38.9 o C, and its molar enthalpy of fusion is H
More informationELECTROCHEMISTRY OXIDATION-REDUCTION
ELECTROCHEMISTRY Electrochemistry involves the relationship between electrical energy and chemical energy. OXIDATION-REDUCTION REACTIONS SPONTANEOUS REACTIONS Can extract electrical energy from these.
More informationElectrochem: It s Got Potential!
Electrochem: It s Got Potential! Presented by: Denise DeMartino Westlake High School, Eanes ISD Pre-AP, AP, and Advanced Placement are registered trademarks of the College Board, which was not involved
More informationBrass, a solid solution of Zn and Cu, is used to make musical instruments and many other objects.
Brass, a solid solution of Zn and Cu, is used to make musical instruments and many other objects. 14.1 General Properties of Solutions 14.2 Solubility 14.3 Rate of Dissolving Solids 14.4 Concentration
More informationM = Molarity = mol solute L solution. PV = nrt % yield = actual yield x 100 theoretical yield. PM=dRT where d=density, M=molar mass
Solubility Rules: 1. Most nitrate salts are soluble. 2. Most salts of alkali metals and ammonium cations are soluble. 3. Most chloride, bromide and iodide salts are soluble. Exceptions: salts containing
More informationI. (40 points) A. (11 points) 1. Write the ions present in solution after Ba(OH) 2 reacts completely with nitric acid
I. (40 points) A. (11 points) 1. Write the ions present in solution after Ba(OH) 2 reacts completely with nitric acid 2. Write balanced net ionic equations for the reactions between aqueous solutions of
More information10/16/2018. Why study gases? An understanding of real world phenomena. An understanding of how science works.
10/16/018 Kinetic Theory and the Behavior of Ideal & Real Gases Why study gases? An understanding of real world phenomena. An understanding of how science works. 1 10/16/018 A Gas Uniformly fills any container.
More informationPressure. Pressure Units. Molecular Speed and Energy. Molecular Speed and Energy
Pressure is defined as force per unit area. Pressure Pressure is measured with a device called a barometer. A mercury barometer uses the weight of a column of Hg to determine the pressure of gas pushing
More informationActivities and Activity Coefficients
CHEM 331 Physical Chemistry Fall 017 Activities and Activity Coefficients We now finish answering the question we asked during our last lecture, what is the form of the chemical potential i (T,P,x i )
More informationExam3Fall2009thermoelectro
Exam3Fall2009thermoelectro Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. Thermodynamics can be used to determine all of the following EXCEPT
More informationPractice Final CH142, Spring 2012
Practice Final CH142, Spring 2012 First here are a group of practice problems on Latimer Diagrams: 1. The Latimer diagram for nitrogen oxides in given below. Is NO stable with respect to disproportionation
More informationElectrochemical Reactions
1 of 20 4/11/2016 1:00 PM Electrochemical Reactions Electrochemical Reactions Electrical Work From Spontaneous Oxidation- Reduction Reactions Predicting Spontaneous Redox Reactions from the Sign of E Line
More informationChemistry 102 Chapter 19 OXIDATION-REDUCTION REACTIONS
OXIDATION-REDUCTION REACTIONS Some of the most important reaction in chemistry are oxidation-reduction (redox) reactions. In these reactions, electrons transfer from one reactant to the other. The rusting
More informationChapter 20 Electrochemistry
Chapter 20 Electrochemistry Learning goals and key skills: Identify oxidation, reduction, oxidizing agent, and reducing agent in a chemical equation Complete and balance redox equations using the method
More informationName AP Chemistry / / Chapter 5 Collected AP Exam Free Response Questions Answers
Name AP Chemistry / / Chapter 5 Collected AP Exam Free Response Questions 1980 2010 - Answers 1982 - #5 (a) From the standpoint of the kinetic-molecular theory, discuss briefly the properties of gas molecules
More informationCHEM1901/ J-8 June 2013
CHEM1901/3 2013-J-8 June 2013 The atmosphere of Venus contains 96.5 % CO 2 at 95 atm of pressure, leading to an average global surface temperature of 462 C. The energy density of solar radiation striking
More informationChapter 4 Chemical Formulas, Reactions, Redox and Solutions
Terms to Know: Solubility Solute Solvent Solution Chapter 4 the amount of substance that dissolves in a given volume of solvent at a given temperature. a substance dissolved in a liquid to form a solution
More informationKINETIC MOLECULAR DESCRIPTION OF THE STATES OF MATTER
KINETIC MOLECULAR DESCRIPTION OF THE STATES OF MATTER CHAPTER 9 The Gaseous State CHAPTER 10 Solids, Liquids, and Phase Transitions CHAPTER 11 Solutions 392 Gas Liquid Solid 9 THE GASEOUS STATE 9.1 The
More informationElectrochemical Cells
Electrochemistry Electrochemical Cells The Voltaic Cell Electrochemical Cell = device that generates electricity through redox rxns 1 Voltaic (Galvanic) Cell An electrochemical cell that produces an electrical
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 informationChem 1A Dr. White Fall Handout 4
Chem 1A Dr. White Fall 2014 1 Handout 4 4.4 Types of Chemical Reactions (Overview) A. Non-Redox Rxns B. Oxidation-Reduction (Redox) reactions 4.6. Describing Chemical Reactions in Solution A. Molecular
More informationPart A Answer all questions in this part.
Part A Directions (1-24): For each statement or question, record on your separate answer sheet the number of the word or expression that, of those given, best completes the statement or answers the question.
More informationElectrochemistry objectives
Electrochemistry objectives 1) Understand how a voltaic and electrolytic cell work 2) Be able to tell which substance is being oxidized and reduced and where it is occuring the anode or cathode 3) Students
More informationWhat is the importance of redox reactions? Their importance lies in the fact that we can use the transfer of electrons between species to do useful
What is the importance of redox reactions? Their importance lies in the fact that we can use the transfer of electrons between species to do useful work. This is accomplished by constructing a voltaic
More informationFinal Exam Review-Honors Name Period
Final Exam Review-Honors Name Period This is not a fully comprehensive review packet. This packet is especially lacking practice of explanation type questions!!! You should study all previous review sheets
More informationELECTROCHEMISTRY. these are systems involving oxidation or reduction there are several types METALS IN CONTACT WITH SOLUTIONS OF THEIR IONS
Electrochemistry 1 ELECTROCHEMISTRY REDOX Reduction gain of electrons Cu 2+ (aq) + 2e > Cu(s) Oxidation removal of electrons Zn(s) > Zn 2+ (aq) + 2e HALF CELLS these are systems involving oxidation or
More informationChapter 10 Gases Characteristics of Gases Elements that exist as gases: Noble gases, O 2, N 2,H 2, F 2 and Cl 2. (For compounds see table 10.
Chapter 10 Gases 10.1 Characteristics of Gases Elements that exist as gases: Noble gases, O 2, N 2,H 2, F 2 and Cl 2. (For compounds see table 10.1) Unlike liquids and solids, gases expand to fill their
More information3 (4 + 3x6 +2)e- = 24e -
Chemical Bonds Atomic radii increase right to left across the period, and top to bottom down the group pposite is true for ionization energy Covalent bonds are made when difference in electronegativity
More informationSectional Solutions Key
Sectional Solutions Key 1. For the equilibrium: 2SO 2 (g) + O 2 (g) 2SO 3 (g) + 188 kj, the number of moles of sulfur trioxide will increase if: a. the temperature of the system is increased (at constant
More informationChemistry 2000 (Spring 2014) Problem Set #7: Redox Reactions and Electrochemistry Solutions
Chemistry 2000 (Spring 2014) Problem Set #7: Redox Reactions and Electrochemistry Solutions Answers to Questions in Silberberg (only those w/out answers at the back of the book) 192 An electrochemical
More information3. Liquid solutions: a. liquid - liquid Ex. vinegar b. solid - liquid Ex. salt water c. gas - liquid Ex. carbonated water in soda pop
Solution Chemistry Nature of Solutions solutions are homogeneous mixtures substances in solution are different from their solid, liquid or gas forms there should be no observable segregation of component
More informationChemistry 51 Chapter 8 TYPES OF SOLUTIONS. Some Examples of Solutions. Type Example Solute Solvent Gas in gas Air Oxygen (gas) Nitrogen (gas)
TYPES OF SOLUTIONS A solution is a homogeneous mixture of two substances: a solute and a solvent. Solute: substance being dissolved; present in lesser amount. Solvent: substance doing the dissolving; present
More informationCHEM Pharmacy Week 9: Nernst Equation. Dr. Siegbert Schmid School of Chemistry, Rm 223 Phone:
CHEM1612 - Pharmacy Week 9: Nernst Equation Dr. Siegbert Schmid School of Chemistry, Rm 223 Phone: 9351 4196 E-mail: siegbert.schmid@sydney.edu.au Unless otherwise stated, all images in this file have
More informationCHEM N-12 November In the electrolytic production of Al, what mass of Al can be deposited in 2.00 hours by a current of 1.8 A?
CHEM161 014-N-1 November 014 In the electrolytic production of Al, what mass of Al can be deposited in.00 hours by a current of 1.8 A? What products would you expect at the anode and the cathode on electrolysis
More informationGases. A gas. Difference between gas and vapor: Why Study Gases?
Gases Chapter 5 Gases A gas Uniformly fills any container. Is easily compressed. Mixes completely with any other gas. Exerts pressure on its surroundings. Difference between gas and vapor: A gas is a substance
More informationCHEMISTRY 202 Hour Exam I. Dr. D. DeCoste T.A.
CHEMISTRY 202 Hour Exam I September 28, 2017 Dr. D. DeCoste Name Signature T.A. This exam contains 23 questions on 10 numbered pages. Check now to make sure you have a complete exam. You have two hours
More informationThermodynamics IV - Free Energy and Chemical Equilibria Chemical Potential (Partial Molar Gibbs Free Energy)
Thermodynamics IV - Free Energy and Chemical Equilibria Chemical Potential (Partial Molar Gibbs Free Energy) increase in the Gibbs free energy of the system when 1 mole of i is added to a large amount
More informationElectrochemistry. The study of the interchange of chemical and electrical energy.
Electrochemistry The study of the interchange of chemical and electrical energy. Oxidation-reduction (redox) reaction: involves a transfer of electrons from the reducing agent to the oxidizing agent. oxidation:
More informationMixtures. Chapters 12/13: Solutions and Colligative Properties. Types of Solutions. Suspensions. The Tyndall Effect: Colloid
Mixtures Chapters 12/13: Solutions and Colligative Properties Solution - a homogeneous mixture of two or more substances in a single phase Soluble - capable of being dissolved Solutions - 2 Parts Solvent
More informationChapter 10. Gases. The Gas Laws
Page 1 of 12 10.1 Characteristics of Gases. Chapter 10. Gases. All substances have three phases; solid, liquid and gas. Substances that are liquids or solids under ordinary conditions may also exist as
More informationChemistry 222 Exam 4: Chapters 11, 13, 14 Spring Points
Chemistry 222 Name Exam 4: Chapters 11, 13, 14 Spring 2014 80 Points Complete five (5) of the following problems. Each problem is worth 16 points. CLEARLY mark the problems you do not want graded. You
More informationA Gas Uniformly fills any container. Easily compressed. Mixes completely with any other gas. Exerts pressure on its surroundings.
Chapter 5 Gases Chapter 5 A Gas Uniformly fills any container. Easily compressed. Mixes completely with any other gas. Exerts pressure on its surroundings. Copyright Cengage Learning. All rights reserved
More informationChapter 20. Electrochemistry
Chapter 20. Electrochemistry 20.1 Oxidation-Reduction Reactions Oxidation-reduction reactions = chemical reactions in which the oxidation state of one or more substance changes (redox reactions). Recall:
More informationDr. Anand Gupta
By Dr Anand Gupta Mr. Mahesh Kapil Dr. Anand Gupta 09356511518 09888711209 anandu71@yahoo.com mkapil_foru@yahoo.com Electrochemistry Electrolysis Electric energy Chemical energy Galvanic cell 2 Electrochemistry
More informationChapter Nineteen. Electrochemistry
Chapter Nineteen Electrochemistry 1 Electrochemistry The study of chemical reactions through electrical circuits. Monitor redox reactions by controlling electron transfer REDOX: Shorthand for REDuction-OXidation
More informationName AP CHEM / / Collected Essays Chapter 17
Name AP CHEM / / Collected Essays Chapter 17 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 reaction
More informationSolutions CHAPTER OUTLINE
Chapter 8A Solutions 1 CHAPTER OUTLINE Type of Solutions Electrolytes & Nonelectrolytes Equivalents of Electrolytes Solubility & Saturation Soluble & Insoluble Salts Formation of a Solid Precipitation
More informationName (Print) Section # or TA. 1. You may use a crib sheet which you prepared in your own handwriting. This may be
Name (Print) Section # or TA 1. You may use a crib sheet which you prepared in your own handwriting. This may be one 8-1/2 by 11 inch sheet of paper with handwriting only on one side. 2. You may use a
More informationCHM 2046 Final Exam Review: Chapters 11 18
Chapter 11 1. Which of the following has the lowest boiling point? a. NH 3 b. CH 3 Cl c. NaCl d. CO 2 e. CH 3 CH 2 CH 2 CH 2 CH 3 2. Which of the following has the lowest vapor pressure? a. CH 3 F b. CH
More informationWorksheet 1.1. Chapter 1: Quantitative chemistry glossary
Worksheet 1.1 Chapter 1: Quantitative chemistry glossary Amount The number of moles of a substance present in a sample. Aqueous solution A solution with water as the solvent. Atmosphere The unit atmosphere
More informationChapter 16. Solubility and Complex Ion Equilibria
Chapter 16 Solubility and Complex Ion Equilibria Section 16.1 Solubility Equilibria and the Solubility Product Solubility Equilibria Solubility product (K sp ) equilibrium constant; has only one value
More informationDATA THAT YOU MAY USE UNITS Conventional Volume ml or cm 3 = cm 3 or 10-3 dm 3 Liter (L) = dm 3 Pressure atm = 760 torr = Pa CONSTANTS
DATA THAT YOU MAY USE UNITS Conventional S.I. Volume ml or cm 3 = cm 3 or 0-3 dm 3 Liter (L) = dm 3 Pressure atm = 760 torr =.03 0 5 Pa torr = 33.3 Pa Temperature C 0 C = 73.5 K PV L-atm =.03 0 5 dm 3
More informationAP* Electrochemistry Free Response Questions page 1
Galvanic (Voltaic) Cells 1988 Average score = 5.02 a) two points Sn ---> Sn 2+ + 2e Ag + + e ---> Ag AP* Electrochemistry Free Response Questions page 1 b) two points 2 Ag + + Sn ---> 2 Ag + Sn 2+ E =
More informationChapter 5. The Gas Laws
Chapter 5 The Gas Laws 1 Pressure Force per unit area. Gas molecules fill container. Molecules move around and hit sides. Collisions are the force. Container has the area. Measured with a barometer. 2
More informationElectrochemical Cells at Non-Standard Conditions
Electrochemical Cells at Non-Standard Conditions Oxidation-reduction reactions in the real world rarely occur under standard conditions. Even if the cell started out with all dissolved species at 1M concentration,
More informationName Section Number TA. 1. You may use crib sheets which you prepared in your own handwriting. This may be up to
1. You may use crib sheets which you prepared in your own handwriting. This may be up to five 8-1/2 by 11 inch sheets of paper with handwriting only on one side. This corresponds to one page each for Chapters
More informationCHEMISTRY 202 Hour Exam I. Dr. D. DeCoste T.A.
CHEMISTRY 0 Hour Exam I September, 016 Dr. D. DeCoste Name Signature T.A. This exam contains 3 questions on 11 numbered pages. Check now to make sure you have a complete exam. You have two hours to complete
More informationLecture 6. NONELECTROLYTE SOLUTONS
Lecture 6. NONELECTROLYTE SOLUTONS NONELECTROLYTE SOLUTIONS SOLUTIONS single phase homogeneous mixture of two or more components NONELECTROLYTES do not contain ionic species. CONCENTRATION UNITS percent
More information4. [7 points] Which of the following reagents would decrease the solubility of AgCl(s)? NaOH HCl NH 3 NaCN
1. [7 points] It takes 0.098 g of silver iodate, AgIO 3, to make 1.00-L of a saturated solution saturated at 25 C. What is the value of the solubility product, K sp? a. 3.5 10 4 b. 1.2 10 7 c. 9.8 10 2
More informationCHEMISTRY 202 Hour Exam I. Dr. D. DeCoste T.A.
CHEMISTRY 202 Hour Exam I September 22, 2016 Dr. D. DeCoste Name Signature T.A. This exam contains 23 questions on 11 numbered pages. Check now to make sure you have a complete exam. You have two hours
More informationChemistry Joke. Once you ve seen 6.02 x You ve seen a mole!
States of Matter Chemistry Joke Once you ve seen 6.02 x 10 23 atoms You ve seen a mole! Kinetic Theory Kinetic Theory explains the states of matter based on the concept that the particles in all forms
More informationCHEMISTRY 102A Spring 2012 Hour Exam II. 1. My answers for this Chemistry 102 exam should be graded with the answer sheet associated with:
. My answers for this Chemistry 0 exam should be graded with the answer sheet associated with: a) Form A b) Form B c) Form C d) Form D e) Form E. A sample of LSD (D-lysergic acid diethylamide, C 4 H 30
More information1. Forming a Precipitate 2. Solubility Product Constant (One Source of Ions)
Chemistry 12 Solubility Equilibrium II Name: Date: Block: 1. Forming a Precipitate 2. Solubility Product Constant (One Source of Ions) Forming a Precipitate Example: A solution may contain the ions Ca
More informationElectron Transfer Reactions
ELECTROCHEMISTRY 1 Electron Transfer Reactions 2 Electron transfer reactions are oxidation- reduction or redox reactions. Results in the generation of an electric current (electricity) or be caused by
More informationL = 6.02 x mol Determine the number of particles and the amount of substance (in moles)
1.1 The Mole 1.1.1 - Apply the mole concept to substances A mole is the name given to a certain quantity. It represents 6.02 x 10 23 particles. This number is also known as Avogadro's constant, symbolised
More informationCh 17 Solubility Equilibria. Brown & LeMay
Ch 17 Solubility Equilibria Brown & LeMay When a typical ionic solid is dissolved in water that dissolved material can be assumed to be present as separate hydrated anions & cations. For example: CaF 2
More informationWksht 4.2 Aqueous Equilibria II
Wksht 4.2 Aqueous Equilibria II Date: 10/16/17 1. Label the type of titration each graph represents and whether their equivalence point ph values would be greater than, equal to, or less than 7. WA being
More informationCHEM J-14 June 2014
CHEM1101 2014-J-14 June 2014 An electrochemical cell consists of an Fe 2+ /Fe half cell with unknown [Fe 2+ ] and a Sn 2+ /Sn half-cell with [Sn 2+ ] = 1.10 M. The electromotive force (electrical potential)
More informationOxidation (oxidized): the loss of one or more electrons. Reduction (reduced): the gain of one or more electrons
1 of 13 interesting links: Battery Chemistry Tutorial at http://www.powerstream.com/batteryfaq.html Duracell Procell: Battery Chemistry at http://www.duracell.com/procell/chemistries /default.asp I. Oxidation
More informationMelting. Freezing. Triple Point. Sublimation. Deposition. Temperature. 2. How many protons and electrons do the following atoms have?
CST Review Part 2 1. In the phase diagram, correctly label the x-axis and the triple point write the names of all six phases transitions in the arrows provided. Melting Liquid Freezing Pressure (ATM) Solid
More informationElectrochemical Cells
Electrochemical Cells There are two types: Galvanic and Electrolytic Galvanic Cell: a cell in which a is used to produce electrical energy, i.e., Chemical energy is transformed into Electrical energy.
More informationB 2, C 2, N 2. O 2, F 2, Ne 2. Energy order of the p 2p and s 2p orbitals changes across the period.
Chapter 11 Gases Energy order of the p p and s p orbitals changes across the period. Due to lower nuclear charge of B, C & N there is no s-p orbitals interaction Due to high nuclear charge of O, F& Ne
More informationSolutions & Solubility: Net Ionic Equations (9.1 in MHR Chemistry 11)
Solutions & Solubility: Net Ionic Equations (9.1 in MHR Chemistry 11) 1 Solubility vs. Temperature 2 Solubility Table Anions SOLUBILITY Table 8.3 page 363 in MHR Cl Br I S OH SO CO 3 PO 3 SO 3 C 2 H 3
More informationStructure & properties of water
OCN 623 Chemical Oceanography Reading: Libes, Chapter 7 Structure & properties of water Water accounts for 96.5 weight percent of seawater Innate characteristics affect nearly all properties of seawater
More informationChapter 18. Electrochemistry
Chapter 18 Electrochemistry Section 17.1 Spontaneous Processes and Entropy Section 17.1 http://www.bozemanscience.com/ap-chemistry/ Spontaneous Processes and Entropy Section 17.1 Spontaneous Processes
More informationLearning Outcomes: At the end of this assignment, students will be able to:
Chemical Equilibria & Sample Preparation Purpose: The purpose of this assignment is to predict how solute concentrations are controlled by chemical equilibria, understand the chemistry involved with sample
More informationSolubility Equilibria
Chapter 17 SOLUBILITY EQUILIBRIA (Part II) Dr. Al Saadi 1 Solubility Equilibria The concept of chemical equilibrium helps to predict how much of a specific ionic compound (salt) will dissolve in water.
More informationChemistry 112 Name Exam III Form A Section April 2,
Chemistry 112 Name Exam III Form A Section April 2, 2013 email IMPORTANT: On the scantron (answer sheet), you MUST clearly fill your name, your student number, section number, and test form (white cover
More informationResearch tells us fourteen out of any ten individuals like chocolate. Happy Halloween!
CHEMISTRY 101 Hour Exam II October 31, 2006 Adams/Le Name KEY Signature T.A./Section Research tells us fourteen out of any ten individuals like chocolate. Happy Halloween! This exam contains 17 questions
More informationAdvanced Chemistry Final Review
Advanced Chemistry Final Review 1. What are the products of complete combustion of hydrocarbons? Hydrocarbons are compounds made of carbon and oxygen. When they burn (combine with oxygen) they form carbon
More informationReactions in Aqueous Solutions
Reactions in Aqueous Solutions 1 Chapter 4 General Properties of Aqueous Solutions (4.1) Precipitation Reactions (4.2) Acid-Base Reactions (4.3) Oxidation-Reduction Reactions (4.4) Concentration of Solutions
More informationSolubility Equilibrium
2016 Ksp note.notebook Solubility Equilibrium Learning Goals: to understand what happens when a compound dissolves in water to calculate the extent of dissolution...the molar solubility to calculate the
More information10/15/2015. Why study gases? An understanding of real world phenomena. An understanding of how science works.
0/5/05 Kinetic Theory and the Behavior of Ideal & Real Gases Why study gases? An understanding of real world phenomena. An understanding of how science works. 0/5/05 A Gas fills any container. completely
More information