Chem 2 Final

An oxidation-reduction reaction in which 2 electrons are transferred has a ΔG0=18.55 kJ/mol at 25 ℃. What is the value of E0? (Faraday's constant is 96485 C/mol)

-0.096 V

Given the standard reduction potential at 25 ℃, what is the standard cell potential of a Cu(s) | Cu2+ (aq) || Zn2+ (aq)|Zn (s) galvanic cell?

-1. 10 V

An equilibrium mixture of I2 (g), Cl2 (g), and ICl (g) at 298 K has partial pressures of 0.0100 atm, 0.0100 atm, and 0.0900 atm, respectively. What is ΔG0 at 298 K for this reaction? I2 (g) + Cl2 (g) ⇌ 2 ICl (g)

-10.9 kJ/mol

What is the freezing point of an aqueous solution that boils at 106.5 °C? (kb for water is 0.512 °C/m, kf for water is 1.86 °C/m; assuming the van Hoff factor is 1.0)

-23.6 °C

Calculate G at 25 C and determine whether the reaction is spontaneous

-53.3 kJ/mol, spontaneous

Given a HCl solution with a pH of 2.45, what is the molar concentration of the HCl (aq) solution?

0.0035 M

A first-order reaction (AàB) has a half-life of 25 minutes. If the initial concentration of A is 0.300 M, what is the concentration of B after 75 minutes?

0.262 M

Consider the reaction Cu2+ (aq) + Zn (s) à Cu (s) + Zn2+ (aq) E0 = 1.10 V What is the value of E when [Cu2+] is 0.040 M and [Zn2+] is 0.40 M?

1.07 V

What minimum [OH-] triggers the precipitation of the Mg^2+ ion

1.0x10-6 M

Calculate E°cell for the reaction Cu2+(aq) + Zn(s) àCu (s) + Zn2+(aq)

1.10 V

Consider the following reaction. If the initial concentration of A (g) is 0.50 M, what is the equilibrium concentration of CO (g)? A (g) ⇌ B (g) + 2C (g) Kc = 6.6 x 10-8

1.28 x 10-4 M

Consider the titration of 25.0 mL of 0.200 M weak acid HA (Ka is 1.0 x 10-5) with 0.200 M NaOH. What is the pH when 25 mL NaOH was added?

11.06

A 1.2 m aqueous solution of an ionic compound with the formula MX2 has a boiling point of 101.4 °C. What is the van't Hoff factor (i) for MX2 at this concentration?

2.3

What is the free energy change for the formation of one mole of nitrogen from its elements under standard conditions? 2NH3 (g) à N2 (g) + 3H2 (g) ΔG0 = 33.0 kJ/mol

33.0 kJ/mol

Ethanol has a heat of vaporization of 38.56 kJ/mol and a normal boiling point of 78.4 °C. What is the vapor pressure of ethanol at 15 °C? R = 8.314 J/mol•K, Temperature in K = temperature in Celsius +273

41 torr

What is the coefficient for the Fe3+ when the redox reaction is balanced in basic solution? MnO4- (aq) + Fe2+ (aq) à Mn2+ (aq) + Fe3+ (aq)

5

For BaF2 Ksp = 1.0 x 10-6. What is the molar solubility of BaF2?

6.3 x 10-3 M

What volume (in mL) of a soft drink that is 10.5% sucrose (C12H22O11) by mass contains 78.5 g of sucrose? (The density of the solution is 1.04 g/mL)

719 mL

Use the data to find the equilibrium constant (Kc) for reaction A (g) ⇌ 3B (g) + C (g). A (g) ⇌ 3X (g) + C (g) Kc = 1.55 B (g) ⇌ X (g) Kc = 25.2

9.92 x 10^-5

which of the two weak acid solutions is more concentrated? Which of the two acids has the larger Ka?

Acid A is more concentrated and Acid B has the larger Ka

Which gas has the largest molar entropy at 298 K and 1 atm?

Ar

Which compound has the highest molar solubility?

BaCO3, Ksp = 2.58 x 10-9

Which compound do you expect to be most soluble in octane (C8H18)?

CBr4

Which of the following pair cannot form a homogeneous solution when combined at room temperature and normal pressure?

CCl4 and H2O

Which change is likely to be accompanied by an increase in entropy?

CO2 (s) à CO2 (g)

In an electrochemical cell, Q = 1.00 and K = 0.855. What can you conclude about Ecell and E0cell?

Ecell and E°cell are both negative.

Which one of the following acids is not a strong acid?

HNO2

The equilibrium constant of a reaction A(aq) + 2B(s) ⇌ 2C(l) + 4D(aq) + 2E(s) is KC, while the equilibrium constant of reaction C(l) + 2D(aq) + 1E(s) ⇌ (1/2)A(aq) + B(s) is KC' for. Which of the following statement is correct in regard to the equilibrium constants of the two reactions?

KcKc'^2=1 and Kc=[D]^6/[A]

Which of the following salt is acidic?

NH4F

Which reaction is spontaneous?

Pb2+(aq) + Fe(s) àFe2+(aq) + Pb(s) (E°Fe/Fe2+=-0.45 V; E°Pb/Pb2+=-0.13 V)

A solution contains 4.08 g of chloroform (CHCl3) and 9.29 g of acetone (CH3COCH3). The vapor pressures at 35 °C of pure chloroform and pure acetone are 295 torr and 332 torr, respectively. The experimentally measured total vapor pressure of the solution at 35 °C is 312 torr. Which of the following statements is correct?

The chloroform-acetone interactions are stronger than the chloroform-chloroform and acetone-acetone interactions.

When the reaction A ⇌ B reaches equilibrium, which quantity equals zero?

The free energy change, ΔG

Consider the reaction Fe2O3(s) + 3CO(g) ⇌ 2Fe(s) + 3 CO2 (g). Kp is the same as Kc.

True

The electrolysis of water results in oxygen at the anode and hydrogen at the cathode.

True

Warming 100 g of ice from -15 to 0 °C requires more heat than warming 100 g of steam from 100 to 115 °C. (ice heat capacity is 2.09 J/g•℃; steam heat capacity is 2.01 J/g•℃;heat=CmΔT)

True

Given the galvanic cell shown on the right, which statement is correct?

Zn is the anode, Cu is the cathode, Zn is oxidized to Zn2+, Cu2+ is reduced to Cu

Consider the endothermic reaction: NH4 (g) ⇌ NH3 (g) + H2S (g) at a high temperature. Which change to an equilibrium mixture of this reaction results in the formation of more H2S?

an increase in temperature

A sample of the substance in the phase diagram shown below is initially at 195 °C and 925 mmHg. What phase transition occurs when the pressure is decreased to 760 mmHg at constant temperature?

liquid to gas

According to the solubility diagram, a solution contains 25 g of NaCl per 100.0 g of water at 25 °C. Which of the following statements is correct?

the solution is unsaturated.

A reaction is nonspontaneous under a certain set of conditions. What can you conclude about ΔGrxn and Q?

ΔGrxn > 0, Q > K