chem II Final exam review

What is the oxidation number of Br in bromic acid, HBrO3. A. +5 B. +4 C. +7

A. +5

Given that EoCell = +0.47 V for the following cell: Pb(s)|Pb2+ (aq)||Cu2+(aq)|Cu(s) What is standard potential at the Pb electrode? A. -0.13 V B. +0.13 V C. +0.81 V

A. -0.13 V

Hydrazine is used to eliminate dissolved, corrosive oxygen from the water used in high-pressure, high-temperature steam furnaces. In this reaction, the oxidation state of nitrogen changes from __ to __. N2H4(aq) + O2(g) --> N2 (g) + 2H2O (l) A. -2,0 B. -4,0 C. -2,+1 D. +2,0 E. +4,0

A. -2,0

Consider the following cell at standard conditions: Zn(s)|Zn2+ (aq)||Fe2+ (aq)|Fe(s) Calculate the value of Go for the reaction that occurs when current is drawn from this cell at 25 C. A. -61.8 kJ/mol B. -295 kJ/mol C. +61.8 kJ/mol

A. -61.8 kJ/mol

Phosphorus trichloride can be produced according to P2 (g) + 3Cl2 (g) <--> 2PCl3 (g) Go for this reaction at 25 C is -642.9 kJ mol-1. What is the value of G for a reaction mixture, at 25 C, that consists of 1.5 atm P2. 1.6 atm Cl2, and 0.65 atm PCl3? A. -649.5 kJ mol-1 B. -708.4 kJ mol-1 C. -42.2 kJ mol-1

A. -649.5 kJ mol-1

Using the data below, calculate the standard free energy change (in KJ mol-1) for the following reaction at 25 C: CH4(g) + 2O2(g) --> CO2(g) + 2H2O(l) Gf CH4 (g) = -50.8 kJ mol-1 Gf CO2 (g) = -394.4 kJ mol-1 Gf H2O (l) = -237.2 kJ mol-1 A. -818.0 B. -580.8 C. not enough information is given

A. -818.0

In which of the following aqueous solutions would you expect AgCl to have the lowest solubility? A. 0.020 M BaCl2 B. 0.030 M NaCl C. pure water

A. 0.020 M BaCl2

How many electrons are transferred when the following redox reaction is balanced? Fe2+(aq) + Ce4+(aq)--> Fe3+(aq) + Ce3+ (aq) A. 1 B. 6 C. 12

A. 1

A solution of NaF is added drop-wise to a solution that is 0.0144 M in Ba2+. When the concentration of F- exceeds _____, BaF2 will precipitate. Neglect volume changes. Ksp of BaF2 is, 1.7 x 10-6. A. 1.1 x 10-2 B. 92 M C. 5.4 x 10-2

A. 1.1 x 10-2

The oxidation of hydrogen gas by oxygen gas forms the basis of the fuel cell. 2H2(g) + O2(g) --> 2H2O (l) This reaction has a Go value of -474 kJ/mol. What is the standard cell potential for this fuel cell? A. 1.23 V B. 4.91 V C. 2.46 V D. 0.005 V E. 1.54 V

A. 1.23 V

If the equilibrium constant for reaction (1) is K, wha is the equilibrium constant foe reaction (2)? (1) SO2 (g) + 1/2 O2 (g) <--> SO3 (g) (2) 2SO3 (g) <--> 2SO2 (g) + O2(g) A. 1/K2 B. K^2 C. 1/square root of K

A. 1/K2

Determine EoCell for the galvanic cell described by the following reaction. 3Zn(s) + 2Au3+(aq) --> 3Zn2+ (aq)+ 2Au(s) A. 2.26 V B. 5.28 V C. 0.74 V D. 0.72 V E. 13.56 V

A. 2.26 V

The Ksp of MgSO4 is 5.9 x 10-3, What is the molar solubility of magnesium sulfate in 0.1 M MgCl2? A. 4.2 x 10-2 M B. 5.9 x 10-2 M C. 7.7 x 10-2 M D. 3.5 x 10-5 M E. 3.5 x 10-6 M

A. 4.2 x 10-2 M

What is the pH of a solution made by mixing 25.0 mL of 0.10 M acetic acid with 10.0 mL of 0.10 M NaOH? Assume the volumes are additive. Ka = 1.8 X 10-5 for CH3COOH. A. 4.57 B. 4.74 C. 4.92

A. 4.57

What is the pH of a solution prepared by mixing 0.15 mol of acetic acid and 0.30 mol of sodium acetate in sufficient water to make 1.0 L of solution? The Ka of acetic acid is 1.8 x 10-5 A. 5.05 B. 4.74 C. 4.44

A. 5.05

How many minutes will it take to plate out 2.19 g of chromium metal from a solution of Cr3+ using a current of 39.5 amps in an electrolyte cell? A. 5.14 B. 309 C. 103 D. 1.17 E. 15.4

A. 5.14

At 25 C the solubility of Ca(OH)2 in water is 0.011 M. What is the value of Ksp? A. 5.3 x 10-6 B. 2.4 x 10-4 C. 1.3 x 10-6

A. 5.3 x 10-6

How long will it take to deposit 0.00235 moles of gold by electrolytes of KAuCl4(aq) using a current of 0.214 amperes? A. 53.0 min B. 35.3 min C. 2.43 min

A. 53.0 min

What is the pH of a solution whose pOH is 7.85 at 25 C? A. 6.15 B. 7.15 C. 8.15

A. 6.15

Blood, sweat, and tears are about 0.15 M in sodium chloride. Estimate the osmotic pressure of these solutions at 37 C. A. 7.6 atm B. 3.8 atm C. 0.91 atm

A. 7.6 atm

Which of the following substances has the greatest solubility in water? A. Ag2SO4, Ksp = 1.5 x 10-5 B. Ca(OH)2, Ksp = 6.5 x 10-6 C. PbI2, Ksp = 7.9 x 10-9

A. Ag2SO4, Ksp = 1.5 x 10-5

Which of the following is a lewis acid? A. BCl3 B. Cl- C. NH3

A. BCl3

Which of the following choices has the compounds correctly arranged in order of the increasing solubility in water? A. CCl4 < CHCl3 < NaNO3 B. CH3OH < CH4 < LiF C. CH4 < NaNO3 < CHCl3 D. LiF < NaNO3 < CHCl3 E. CH3OH < CCl4 < CHCl3

A. CCl4 < CHCl3 < NaNO3

Which element is oxidized in this reaction? Fe2+ + H+ +Cr2O72- --> Fe3+ + Cr3+ + H2O A. Fe B. Cr C. O D. H

A. Fe

Which of the following is characteristic of a spontaneous reaction? A. Go > 0 B. EoCell > 0 C. K < 1

A. Go > 0

Balance the following rodox reaction if it occurs in acidic solution. What are the coefficients in front of H2C2O4 and H2O In the balanced reaction? MnO4-(aq) + H2C2O4(aq) --> Mn2+(aq) + CO2 (g) A. H2C2O4 = 5 H2O = 8 B. H2C2O4 = 1 H2O = 1 C. H2C2O4 = 5 H2O = 1 D. H2C2O4 = 1 H2O = 4 E. H2C2O4 = 3 H2O = 2

A. H2C2O4 = 5 H2O = 8

Identify the weakest acid. A. H2S B. H2Se C. H2Te

A. H2S

When dissolved in water, which of the following salts will produce the solution with a pH of 7.0 at 25 C. A. KCl B. NaClO C. NH4Cl

A. KCl

What is the relationship between the molar solubility, x, and Ksp for the ionic solid Ca3(PO4)2? A. Ksp = 108x^5 B. Ksp = 5x C. Ksp = x^5

A. Ksp = 108x^5

Write the equilibrium constant expression, Kp, for the following chemical reaction: 2O2 (g) <--> 3O2 (g) A. P3O2/P2O2 B. P2O3/P3O2 C. 3PO2/2PO3

A. P3O2/P2O2

Predict which of the following has the lowest boiling point. A. PH3 B. AsH3 C. NH3

A. PH3

Which of the following is always positive when a spontaneous process occurs? A. S B. Ssurr C. Suni D. Huni E. Hsurr

A. S

Which of the following could be added to a solution of acetic acid to prepare a buffer? A. Sodium hydroxide B. Acetic acid C. Nitric acid

A. Sodium hydroxide

Consider the reaction: N2(g) --> 2N (g) Which of the following statements is true? A. The reaction is spontaneous at high temperatures B. The reaction is spontaneous at low temperatures C. The reaction is spontaneous at all temperatures

A. The reaction is spontaneous at high temperatures

Which of the following statements about Kw is false? A. The value of Kw is always 1.00 x 10-14 B. The value of Kw shows that water is a weak acid C. Kw is known is as the ion product constant of water.

A. The value of Kw is always 1.00 x 10-14

An animal cell assumes its normal volume when it is placed in an aqueous solution with a total solute molarity of 0.3 M. If the cell is placed in an aqueous solution with a total solute molarity of 0.1 M. A. Water enters the cell, causing expansion B. Water leaves the cell causing contraction C. No movement of water takes place.

A. Water enters the cell, causing expansion

Which of the following is a polar compound? A. XeO2 B. XeF2 C. I3-

A. XeO2

Sodium can be produced by the electrolysis of molten sodium chloride. What are the products at the anode and cathode? A. anode: Cl2 (g) and cathode: Na(l) B. anode: Na (l) and cathode: Cl2 (g) C. anode: Cl- (aq) and cathode: Na+ (aq)

A. anode: Cl2 (g) and cathode: Na(l)

Pressure has an appreciable effect on the solubility of __________ in liquids. A. gases B. solids C. liquids D. liquids and gases E. solids and liquids

A. gases

The purpose of the salt bridge in an electrochemical cell is to ____. A. maintain electrical neutrality in the half-cells via migration of ions B. provide a source of ions to react at the anode and cathode C. provide oxygen to facilitate oxidation at the anode D. provide a means for electrons to travel from the anode to the cathode E. provide a means for electrons to travel from the cathode to the anode

A. maintain electrical neutrality in the half-cells via migration of ions

Which of the following is a path function? A. q B. G C. H

A. q

What is the molecular shape of SO32- ? A. trigonal pyramidal B. tetrahedral C. trigonal planar

A. trigonal pyramidal

In which of the following aqueous solutions would you expect AgCl to have the lowest solubility? A. pure water B. 0.02 M BaCl2 C. 0.015 NaCl D. 0.020 AgNO3 E. 0.020 KCl

B. 0.02 M BaCl2

The freezing point of seawater is about -1.85 C. If seawater is an aqueous solution of sodium chloride, calculate the molality of seawater. A. 1.99 m B. 0.497 m C. 0.995 m

B. 0.497 m

A solution of NaF is added dropwise to a solution that is 0.0144 M in Ba2+. What molar concentration of F- is necessary to cause BaF2 to precipitate if the Ksp of BaF2 is 1.7 x 10-6. Neglect any change in volume. A. 5.9 x 10-5 B. 1.1 x 10-2 C. 2.4 x 10-8 D. 2.7 x 10-3 E. 1.2 x 10-4

B. 1.1 x 10-2

What is the coefficient of the permanganate ion when the following equation is balanced under acidic conditions? MnO4- + Br- --> Mn2+ + Br2 A. 1 B. 2 C. 3 D. 4 E. 5

B. 2

What is the pH of a 0.20 M solution of CH3COOH whose Ka = 1.8 x 10-5 A. 2.88 B. 2.72 C. 0.70

B. 2.72

A solution is prepared by dissolving calcium chloride in water and diluting to 500.0 mL. If this solution contains 44 ppm chloride ions, what is the concentration of calcium ions in the solution? A. 11 B. 22 C. 44 D. 88 E. 500

B. 22

A 15.0 M NH3 (aq) solution has a density of 0.900 g mL-1. calculate the molality of this solution. A. 16.7 m B. 23.3 m C. 58.7 m

B. 23.3 m

What is the molar concentration of iodide ions in a saturated aqueous solution of lead (II) iodide? The solubility product of PbI2 is 1.4 x 10-8. A. 3.8 x 10-4 B. 3.0 x 10-3 C. 1.5 x 10-3 D. 3.5 x 10-9 E. 1.4 x 10-8

B. 3.0 x 10-3

Calculate the molality of a 25.4% (by mass) aqueous solution of phosphoric acid (H3PO4). A. 2.59 m B. 3.47 m C. 4.45 m D. 25.4 m E. the density of the solution is needed to solve the problem.

B. 3.47 m

Calculate the solubility of barium carbonate. BaCO3, in pure water. Ksp = 2.0 x 10-9 A. 1.0 x 10-9 B. 4.5 x 10-5 C. 3.2 x 10-5

B. 4.5 x 10-5

What concentration of Mg2+ is needed to cause magnesium fluoride to precipitate from a solution that is 0.10 M NaF? The Ksp of MgF2 s 6.9 x 10-9 A. 2.6 x 10-4 B. 6.9 x 10-7 C. 6.9 x 10-8

B. 6.9 x 10-7

When the following redox reaction is balanced, in acid conditions, with the smallest whole number coefficients, what is the coefficient of Zn(s)? Zn(s) + ReO4- --> Re(s) + Zn2+(aq) A. 2 B. 7 C. 8

B. 7

Which of the following is considered a lewis acid? A. CH3NH2 B. BCl3 C. F- D. BF4- E. CH4

B. BCl3

Which of the following has the lowest standard molar entropy? A. C(graphite) B. C(diamond) C. C60(s)

B. C(diamond)

What is the conjugate acid of HPO2-4? A. PO4 3- B. H2PO4- C. H3PO4

B. H2PO4-

Which of the following acids will have the strongest conjugate base? A. HIO3 B. HIO2 C. HIO4

B. HIO2

Identify the oxidizing agent in the following redox reaction. Hg2+ (aq) + Cu(s) --> Cu2+(aq) + Hg(l) A. Hg2+ (aq) and Cu2+ (aq) B. Hg2+ (aq) C. Cu(s)

B. Hg2+ (aq)

Which of the following substances has the greatest solubility in water? A. MgCO3, Ksp = 3.5 x 10-8 B. NiCO3, Ksp = 1.3 x 10-7 C. AgIO3, Ksp = 3.1 x 10-8 D. CuBr, Ksp = 5.0 x 10-9 E. AgCN, Ksp = 2.2 x 10-16

B. NiCO3, Ksp = 1.3 x 10-7

Which statement is true for an unsaturated solution? A. Q > Ksp B. Q < Ksp C. Q = Ksp D. Q =/ Ksp E. none of the above

B. Q < Ksp

Consider the reaction: C2H6 (g) --> C2H4 (g) + H2 (g) Given that Hrxn = +137 kJ mol-1 and Srxn = +120 J K-1 mol-1, this reaction is ___. A. Spontaneous at all temperatures B. Spontaneous only at high temperature C. Spontaneous only at low temperature D. nonspontaneous at all temperatures

B. Spontaneous only at high temperature

Which of the following concentration units varies with temperature? A. mole fraction B. molarity C. molality

B. molarity

Concerning galvanic cells, which statement is false? A. cations from the salt bridge move toward the cathode B. the anode is positively charged C. electrons flow from the anode to the cathode D. reduction occurs at the cathode E. only one statement is false

B. the anode is positively charged

A reaction that is spontaneous as written _____. A. is very rapid B. will proceed without outside intervention C. is also spontaneous in the reverse direction D. has an equilibrium position that lies far to the left E. is very slow

B. will proceed without outside intervention

Consider the following cell: Ag(s)|Ag+(aq, 0.100 M)||Ag+(aq,0.100 M)|Ag(s) What is Ecell? A. +0.80 V B. -0.80 V C. 0.00 V

C. 0.00 V

A 0.15 M solution of a weak acid, at 25 C, has pH of 5.35. What is the value of Ka for this acid? A. 1.8 X 10-5 B. 7.1 X 10-9 C. 1.3 X 10-10

C. 1.3 X 10-10

Adding 125 mg of caffeine (a non-electrolyte) to 100g of cyclohexane lowered the freezing point by 0.13 K. Calculate the molar mass of caffeine. A. 17.9 g mol-1 B. 481 g mol-1 C. 192 g mol-1

C. 192 g mol-1

Which of the following equilibria will shift left in response to a decrease in volume? A. H2 (g) + Cl2 (g) <--> 2HCl (g) B. N2 (g) + 3H2 (g) <--> 2NH3 (g) C. 2SO3 <--> 2SO2 (g) + O2 (g)

C. 2SO3 <--> 2SO2 (g) + O2 (g)

Calculate the boiling point of carbon tetrachloride if the standard entropy and enthalpy of vaporization are +92.82 J K-1 mol-1 and +32.54 kJ mol-1, respectively. A. 2.85 K B. 285 K C. 351 K

C. 351 K

What is the pH of a 0.20 M NH4NO3 solution at 25 C. The Kb of NH3 is 1.8 x 10-5. A. 2.72 B. 9.26 C. 4.98

C. 4.98

What is the value of the equilibrium constant for the cell reaction below at 25 C given that EoCell = +0.61 V ? 2Cr(s) + 3Pb2+(aq) --> 3Pb(s) + 2Cr3+ (aq) A. >9.9 X 10^99 B. 8.6 X 10^30 C. 7.4 X 10^61

C. 7.4 X 10^61

What is the pH of a solution whose [H3O+] = 3.98 x 10-9? A. 3.980 B. 5.600 C. 8.400

C. 8.400

Which of the following reactions would have the smallest value of K at 298 K? A. A + B --> C EoCell=1.22 V B. A + 2B --> C EoCell = 0.98 V C. A + B --> 2C EoCell = -0.030 V D. A + B --> 3C EoCell = 0.15 V E. More information is needed to determine.

C. A + B --> 2C EoCell = -0.030 V

Which of the following is a non-electrolyte? A. HCl B. Rb2SO4 C. Ar D. KOH E. NaCl

C. Ar

Calculate EoCell and indicate whether the overall reaction shown is spontaneous or non-spontaneous. I2(s) + 2e- <--> 2I- (aq); Cr3+ (aq) + 3e- <--> Cr(s); overall reaction: 2Cr(s) + 3I2(s) --> 2Cr3+(aq) + 6I-(aq) A. EoCell = -1.27 V, spontaneous B. EoCell = -1.27 V, non-spontaneous C. EoCell = +1.27 V, spontaneous D. EoCell = +1.27 V, non-spontaneous E. EoCell = +1.54 V, spontaneous

C. EoCell = +1.27 V, spontaneous

Which relationship is always true for a spontaneous reaction at constant temperature? A. Hrxn > 0 B. Srxn < 0 C. Grxn < 0

C. Grxn < 0

Which species has the larger entropy? A. HCl (l) B. HCl (s) C. HCl (g) D. HBr (g) E. HI (g)

C. HCl (g)

Which of the following cannot form intermolecular hydrogen bonds? A. NH3 B. CH3COOH C. HI

C. HI

Consider a electrochemical cell based on the following redox reaction at 25C (1 atm): 2Fe(s) + Cu2+ (aq) --> 2Fe2+(aq) + Cu(s) Which of the following statements is/are true at the point in time when this cell reaches equilibrium? I. Ecell = 0 II.[Cu2+] = [Fe2+] III. No work can be done by this cell. IV. EoCell = 0 A. I, II, and III only B. II and IV only C. I and III only D. II, III, and IV only E. I only

C. I and III only

Which of the following 1.0 M solutions contains the most particles? A. MgSO4 B. KCl C. Na2SO4

C. Na2SO4

Which of the following is more soluble in 1.0 M HClO4(aq) than pure water? A. AgClO4 B. PbI2 C. PbF2

C. PbF2

Which of the following is not equal to zero at 298 K? A. Gf N2 (g) B. Hf N2 (g) C. S N2 (g)

C. S N2 (g)

The entropy change accompanying any process can be computed by which equation? A. S = k ln Wf B. S= k Wf - k Wi C. S= k ln Wf/Wi D. S= kf - ki E. S= Wf - Wi

C. S= k ln Wf/Wi

Which of the following is always positive for a spontaneous change? A. Ssurr B. Ssys C. Suni

C. Suni

Which of the following is not a state function? A. H B. S C. U D. G E. q

C. U

A galvanic cell is prepared using zinc and gold. Its cell notation is: Zn(s)|Zn2+ (aq, 1 M)||Au3+ (aq, 1 M)|Au(s) A. Au(s) --> Au3+(aq) + 3e- B. Au3+(aq) + 3e- --> Au(s) C. Zn(s) --> Zn2+(aq) + 2e- D. Zn2+(aq)+2e- --> Zn(s) E. 3Zn(s) + 2Au3+(aq) --> 3Zn2+(aq) + 2Au(s)

C. Zn(s) --> Zn2+(aq) + 2e-

One of the differences between a galvanic (voltaic) cell and an electrolytic cell that in an electrolytic cell ______. A. an electric current is produced by a chemical reaction B. electrons flow toward the anode C. a non-spontaneous reaction is forced to occur D. O2 gas is produced at the cathode E. oxidation occurs at the cathode

C. a non-spontaneous reaction is forced to occur

If an equal number of moles of HCN and KOH are added in water, is the resulting solution acidic. basic. or neutral? A. Neutral B. Acidic C. Basic

C. basic

Which one of the following will change the value of an equilibrium constant? A. adding substances that do not react with any of the species involved in the equilibrium B. changing the volume of the reaction vessel C. changing temperature

C. changing temperature

The dissolution of gases in water is always exothermic because A. the formation of solute-solvent interactions is unnecessary B. the disruption of solvent-solvent interactions is unnecessary C. the disruption of solute-solute interactions is unnecessary

C. the disruption of solute-solute interactions is unnecessary

At equilibrium__________________. A. the reverse process is spontaneous but the forward process is not B. the forward process is spontaneous but the reverse process is not C. the process is not spontaneous in either direction

C. the process is not spontaneous in either direction

Write the solubility product (or ion product) expression for calcium phosphate. Ca3(PO4)2. A.[Ca2+][PO43-] B. [Ca2+]^2[PO43-]^3 C.[Ca2+]^3[PO43-]^2 D. [Ca2+][PO43-]/[Ca3/(PO4)2] E. none of these are correct

C.[Ca2+]^3[PO43-]^2

The voltaic cell made of cobalt, copper and their M2+ ions, had EoCell = +0.62 V. If EoRed of the cathode half-cell is 0.34 V, what is EoOx of the anode half-cell? Cu2+(aq)+Co(s) --> Cu(s) + CO2+(aq) A. -0.28 V B. +0.96 V C. -0.96 V D. +0.28 V E. None of these choices is correct.

D. +0.28 V

What is the oxidation number of nitrogen in the HNO3? A. -1 B. +1 C. +3 D. +5 E. +7

D. +5

The solubility of lead (II) chloride (PbCl2) is 1.6 x 10-2 M. What is the Ksp of PbCl2? A. 5.0 x 10-4 B. 4.1 x 10-6 C. 3.1 x 10-7 D. 1.6 x 10-5 E. 1.6 x 10-2

D. 1.6 x 10-5

What is the ideal value of i for (NH4)3PO4? A. 1 B. 2 C. 3 D. 4 E. 5

D. 4

Which of the following substances has london dispersion forces as its only intermolecular force? A. CH3OH B. NH3 C. H2O D. CCl4 E. HCl

D. CCl4

Which of the following processes produces a decrease in the entropy of the system? A. boiling water to form steam B. dissolution of solid KCl in water C. mixing of two gases into one container D. Freezing water to form ice E. melting ice to form water

D. Freezing water to form ice

Which compound produces the greatest number of ions when one mole dissolves in water? A. NaCl B. NH4NO3 C. NH4Cl D. Na2SO4 E. sucrose

D. Na2SO4

When argon is placed in a container of neon, the argon spontaneously disperses throughout the neon because ______. A. of the large attractive forces between argon and neon atoms B. of hydrogen bonding C. a decrease in energy occurs when the two mix D. the dispersion of argon atoms produces an increase in disorder E. of solvent-solute interactions

D. the dispersion of argon atoms produces an increase in disorder

Calculate the freezing point of a 0.08500 m aqueous solution of NaNO3. The molal freezing-point-depression constant of water is 1.86 C m-1 A. 0.0425 C B. -0.0790 C C. 0.0790 C D. -0.158 C E. -0.316 C

E. -0.316 C

A solution containing 10.0 g of an unknown liquid and 90.0 g water has a freezing point of -3.33 C. Given Kf = 1.86 C m-1 for water, what is the molar mass of the unknown liquid? A. 69.0 g mol-1 B. 333 g mol-1 C. 619 g mol-1 D. 161 g mol-1 E. 62.1 g mol-1

E. 62.1 g mol-1