Chem 2 final

If G for the following reaction is -324 kJ, calculate .Cr2O72-(aq) + 2 Fe(s) + 14 H+(aq) 2 Cr3+(aq) + 2 Fe3+(aq) + 7 H2O()

+0.560 V

Calculate the standard entropy change for the following reaction,2 HgO(s) 2 Hg(liq) + O2(g)given S[HgO] = 70.3 J/K·mol, S[ Hg(l)] =76.0 J/K·mol S[O2(g)] = 205.1 J/K·mol.

+216.5 J/K

Calculate the standard entropy change for the combustion of ethanol at 25 C. CH3CH2OH( ) + 3 O2(g) 2 CO2(g) + 3 H2O(g)Species S (J/Kmol)CH3CH2OH( ) 160.7O2(g) 205.1CO2(g) 213.7H2O(g) 188.8

+217.8 J/K

Calculate E for the system in which 16 J of work is done on a gas by the surroundings and the gas absorbs 51 J of heat?

+35 J

Calculate for the reaction below at 25.0 C2 H2O(g) + S(s) 2 H2S(g) + O2(g)given = +442.4 kJ and = +206.9 J/K.

+380.7 kJ

Determine the heat of vaporization of titanium(IV) chloride given the enthalpies of reaction below.Ti(s) + 2 Cl2(g) TiCl4(liq) H = -804.2 kJTi(s) + 2 Cl2(g) TiCl4(g) H = -763.2 kJ

+41.0 kJ

For the combustion of acetylene at 298.15 K, 2 C2H2(g) + 5 O2(g) 4 CO2(g) + 2 H2O(g)calculate S(universe) given S(system) = -194.6 J/K and H(system) = -2511.2 kJ.

+8228.0 J/K

For the following reaction at 25.0 C,2 C(s) + O2(g) 2 CO(g)calculate given = 179.1 J/K and = -221.1 kJ.

+920.7 J/K

Calculate for the reaction below,Tl+(aq) + 2 Cl-(aq) 2 Tl(s) + Cl2(g)given the following standard reduction potentials.Cl2(g) + 2 e- 2 Cl-(aq) E = +1.36 VTl+(aq) + e- Tl(s) E = -0.34 V

-1.70 V

The heat of vaporization of bromine is 29.6 kJ/mol at its boiling point of 59 C. What quantity of heat is released when 10.0 g Br2 is condensed at 59 C?

-1.85 kJ

The standard enthalpy change for the combustion of 1 mole of propane is -2043.0 kJ. C3H8(g) + 5 O2(g) 3 CO2(g) + 4 H2O(g)Calculate fH for propane based on the following standard molar enthalpies of formation.molecule fH (kJ/mol-rxn)CO2(g) -393.5H2O(g) -241.8

-104.7 kJ/mol-rxn

Calculate rH for the combustion of ammonia, 4 NH3(g) + 7 O2(g) 4 NO2(g) + 6 H2O( )using standard molar enthalpies of formation.molecule fH (kJ/mol-rxn)NH3(g) -45.9 NO2(g) +33.1H2O( ) -285.8

-1398.8 kJ/mol-rxn

2H2O2 ---- 2H2O + O2 H0= - 211.4kJH2 + O2 --- H2O2 H0= - 136.1kJKonwing the reations above, calculate the H0 per mol for the reaction 2H2 + O2 -- 2H2O

-241.8kJ

Calculate for sulfur dioxide,S(s) + O2(g) SO2(g)given the thermochemical equations below.2 S(s) + 3 O2(g) 2 SO3(g) H = -791.5 kJ2 SO2(g) + O2(g) 2 SO3(g) H = -197.9 kJ

-296.8 kJ/mol

for the following galvanic cell is +0.254 V.Hg22+(aq) + 2 I-(aq) 2 Hg() + I2(s)What is G for this reaction?

-49.0 kJ

Ammonia, NH3, is used as a refrigerant. At its boiling point of -33 C, the standard enthalpy of vaporization of ammonia is 23.3 kJ/mol. How much heat is released when 50.0 g of ammonia is condensed at -33 C?

-68.4 kJ

Given thatS(g) + O2(g) SO2(g) rG = -300.1 kJ/mol-rxn2 S(g) + 3 O2(g) 2 SO3(g) rG = -742.1 kJ/mol-rxncalculate fG of the following reaction: SO2(g) + 1/2 O2(g) SO3(g)

-71.0 kJ/mol-rxn

The freezing point depression constant for water is -1.86 C/m. At what temperature will a solution containing 7.75 g KCl and 45.0 g H2O begin to freeze? Assume that no ion-pairing occurs between K+ and Cl-.

-8.59 C

What is the mole fraction of 1.98 m Fe(NO3)3(aq)? The molar mass of Fe(NO3)3 is 241.9 g/mol and the molar mass of water is 18.02 g/mol.

0.0345

At 0.982 atm, the height of mercury in a barometer is 0.746 m. If the mercury were replaced with ethanol, what height of ethanol (in meters) would be supported at this pressure? The densities of Hg and ethanol are 13.5 g/cm3 and 0.789 g/cm3, respectively.

0.0436 m

If the molarity of oxygen in air is 0.00821 mol/L at 25 C, what is the pressure of oxygen at 25 C? (R = 0.08206 L·atm/mol·K)

0.201 atm

A mixture of He and O2 is placed in a 4.00 L flask at 32 C. The partial pressure of the He is 2.7 atm and the partial pressure of the O2 is 1.4 atm. What is the mole fraction of O2?

0.341

The pressure in a 20.0 L flask is 0.512 atm at 72 C. How many moles of gas are in the flask? (R = 0.08206 L·atm/mol·K)

0.362 mol

When 27.0 g of an unknown metal at 88.4 C is placed in 115 g H2O at 21.0 C, the final temperature of the water is 23.7 C. What is the specific heat capacity of the metal? The specific heat capacity of water is 4.184 J/g·K.

0.74 J/g·K

The lid is tightly sealed on a rigid flask containing 2.00 L O2 at 15 C and 0.723 atm. If the flask is heated to 55 C, what is the pressure in the flask?

0.823 atm

if 3.67 g CO2 gas is introduced into an empty 2.50 L flask at 65 C, what is the pressure inside the flask? (R = 0.08206 L·atm/mol·K)

0.925 atm

Which of the following aqueous solutions should have the lowest freezing point?

1 m Ca(NO3)2

Which of the following relationships are true for gases?1. The number of moles of a gas is directly proportional to its volume (at constant pressure).2. The pressure of a gas is inversely proportional to its temperature in Kelvins (at constant volume).3. The volume of a gas is directly proportional to its pressure (at constant temperature).

1 only

Which of the following statements concerning the phase diagram below are CORRECT? 1. Moving from point D to C results in a phase equilibrium from solid,liquid,gas to liquid-gas equilibrium2. Point D lies at the critical point.3. At point C,solid and gas phases coexist at equilibrium.

1 only

Which of the following are postulates of kinetic-molecular theory of gases?1. The distance between gas molecules is large in comparison to their size.2. Gas molecules are in constant, random motion.3. The kinetic energy of gas particles is proportional to the Kelvin temperature

1, 2, and 3

Which of the following liquids are likely to be miscible with water: 1-propanol (CH3CH2CH2OH), carbon tetrachloride (CCl4), hexane (C6H14), and acetic acid (CH3CO2H)?

1-propanol and acetic acid

At 0.984 atm, the height of mercury in a barometer is 74.8 cm. If the mercury were replaced with motor oil, what height of oil (in centimeters) would be supported at this pressure? The densities of Hg and oil are 13.5 g/cm3 and 0.80 g/cm3, respectively.Hint: the pressure of a column of any liquid is given by P = d x h x g (d = density, h = height, g = gravity acceleration, a constant)

1.262 103 cm

A balloon is filled with He gas to a volume of 3.22 L at 32 C. The balloon is placed in liquid nitrogen until its temperature reaches -132 C. Assuming the pressure remains constant, what is the volume of the cooled balloon?

1.49 L

What is the molality of 13.82% by mass sulfuric acid? The molar mass of H2SO4 is 98.08 g/mol.

1.635 m

For the reaction 2 NO(g) + Cl2(g) 2 NOCl(g), the rate law is = k[NO]2[Cl2].What are the units of the rate constant where time is measured in seconds?

1/M2·s

Calculate the H if a mol of gas is heated with 1000J of heat and expands its volume by 1L under 1 atm of constant pressure? 1atm.L = 101 Joules

1000J

What is the boiling point of a mixture composed of 85 g HOCH2CH2OH (ethylene glycol) and 125 g H2O? The boiling point elevation constant for H2O is 0.512 C/m.

105.6 C

What is the equilibrium partial pressure of water vapor above a mixture of 24.0 g H2O and 48.0 g CH3CH2OH at 25 C. The partial pressure of pure water at 25.0 C is 23.8 mm Hg. Assume ideal behavior for the solution.

13.4 mm Hg

The standard free energy change associated with the dissolution of ammonium nitrate in water is -6.73 kJ/mol at 298.15 K.NH4NO3(s) NH4NO3(aq)What is the equilibrium constant for the reaction? (R = 8.314 J/Kmol)

15

A 0.225-L flask contains CH4 at 27 C and 318 mm Hg. What is the pressure of the CH4 if the volume is increased to 0.500 L and the temperature increased to 95 C?

176 mm Hg

What is the overall order of the reactionCO(g) + NO2(g) CO2(g) + NO(g)if it proceeds via the following rate expression? = k[CO][NO2]

2

Which reaction is likely to have a negative change in entropy?

2 CO(g) 2 C(s) + O2(g)

The following reaction occurs spontaneously.2 H+(aq) + Ca(s) Ca2+(aq) + H2(g)Write the balanced reduction half-reaction.

2 H+(aq) + 2 e- H2(g)

For which of the following reactions will the entropy of the system decrease?

2 NO2(g) N2O4(g)

Which of the following statements are correct?1. Above the critical pressure, only the solid phase of a pure substance can exist.2. Above the critical temperature, a gas may not be condensed to a liquid.3. At the critical point, three phases (gas, liquid, and solid) may coexist at equilibrium.

2 only

The quantity of heat required to heat 5.01 g of ice from -25.0 C to -10.0 C is 155 J. What is the specific heat capacity of ice?

2.06 J/g·K

What is the half-life for a first-order reaction with a rate constant of 0.291 s-1?

2.38 s

Hydrogen peroxide decays into water and oxygen in a first-order process.H2O2(aq) H2O() + O2(g) At 20.0 C, the rate constant is 1.77 10-5 s-1. If the initial concentration of hydrogen peroxide is 1.2 M, what is the concentration after 7.0 days?

2.7 10-5 M

A 0.561 m solution of an unknown electrolyte depresses the freezing point of water by 2.93 C. What is the van't Hoff factor for this electrolyte? The freezing point depression constant, Kfp, for water is -1.86 C/m.

2.81

Which of the following statements concerning entropy is/are CORRECT?1. The entropy of a substance increases when converted from a liquid to a solid.2. The entropy of a substance decreases as its temperature increases.3. All substances have positive entropy values at temperatures above 0 K

3 only

at constant temperature, 10.0 L of N2 at 0.983 atm is compressed to 2.88 L. What is the final pressure of N2?

3.41 atm

What mass of ethylene glycol, when mixed with 90.5 g H2O, will reduce the equilibrium vapor pressure of H2O from 1.00 atm to 0.500 atm at 100 C. The molar masses of water and ethylene glycol are 18.02 g/mol and 62.07 g/mol, respectively. Assume ideal behavior for the solution.

312 g

If a gas effuses 1.618 times faster than Kr, what is its molar mass?

32.01 g/mol

Ammonia gas is synthesized according to the balanced equation below.N2(g) + 3 H2(g) 2 NH3(g)If 2.75 L N2 react with 7.75 L H2, what is the theoretical yield (in liters) of NH3? Assume that the volumes of reactants and products are measured at the same temperature and pressure.

5.17 L

The vapor pressure of pure water at 50.0 C is 92.5 mm Hg. Calculate the ideal partial pressure of water at this temperature for a mixture of 45.0 g H2O and 55.0 g CH3OH?

54.8 mm Hg

Convert 8.00 atm to mm Hg. (1 atm = 760 mm )

6.08 103 mm Hg

in the reaction below, the rate of formation of O2 is 3.4 10-3 mol/L·s. What is the rate of formation of HF?2 HOF(g) 2 HF(g) + O2(g)

6.8 10-3 mol/L·s

For the second-order reaction below, the concentration of the product, B, after 539 seconds is 0.0811 M. If no B is initially present, and the initial concentration of A is 0.744 M, what is the rate constant?2A B rate = k[A]2 13

7.0 10-4 M-1s-1

The vapor pressure of pure water at 45 C is 71.9 mm Hg. What is the vapor pressure of a mixture of 21.0 g sucrose (C12H22O11, molar mass 342.3 g/mol) and 79.0 g water?

70.9 mm Hg

The specific heat capacity of aluminum is 0.897 J/g·K. What quantity of heat (in joules) is required to heat 15.0 g Al from 22.0 C to 75.0 C?

713 J

A mass of 22.8 g of an unknown gas exerts a pressure of 0.912 atm at 78 C in a 10.0 L flask. What is the molar mass of the gas?

72.0 g/mol

What is the equilibrium partial pressure of water vapor above a mixture of 37.5 g H2O and 62.5 g HOCH2CH2OH at 55 C. The partial pressure of pure water at 55.0 C is 118.0 mm Hg. Assume ideal behavior for the solution.

79.5 mm Hg

A solution is prepared by mixing 66.7 g H2O with 33.3 g HOCH2CH2OH (ethylene glycol). What is the concentration of ethylene glycol in units of molality? The molar masses of water and ethylene glycol are 18.02 g/mol and 62.07 g/mol, respectively.

8.04 m

The Henry's law constant for O2 in water at 25 C is 1.66 10-6 M/mm Hg. What partial pressure of O2 is necessary to achieve an equilibrium concentration of 0.150 M O2?

9.04 104 mm Hg

A tightly sealed 15.0-L flask contains 781 mm Hg of Ar at 30 C. The flask is heated until the pressure is quadrupled. What is the temperature of the gas?

939 C

At constant temperature, 7.72 L of Cl2 at 458 mm Hg is compressed to 3.75 L. What is the final pressure of Cl2?

943 mm Hg

If the same amount of heat is added to 5.00 g samples of each of the metals below, which metal will experience the smallest temperature change?Metal Specific Heat Capacity (J/g·K)Al 0.897Au 0.129Cu 0.385Fe 0.449K 0.753

Al

Consider the following half-reactions:Cu2+(aq) + 2 e- Cu(s) E = +0.34 VSn2+(aq) + 2 e- Sn(s) E = -0.14 VFe2+(aq) + 2 e- Fe(s) E = -0.44 VAl3+(aq) + 3 e- Al(s) E = -1.66 VMg2+(aq) + 2 e- Mg(s) E = -2.37 VWhich of the above metals or metal ions will reduce Fe2+(aq)?

Al(s) and Mg(s)

At what temperatures will a reaction be spontaneous if rH = +62.4 kJ and rS = +301 J/K?

All temperatures above 207 K.

Use the standard reduction potentials below to determine which element or ion is the best oxidizing agent.Br2() + 2 e- 2 Br-(aq) E = +1.08 V Hg2+(aq) + e- Hg() E = +0.86 VNi2+(aq) + 2 e- Ni(s) E = -0.25 V

Br2

Which of the following gases can be liquefied at 25 C?Gas boiling pt. critical temp.CH 4 -161.5 C -82.6 CC 3 H 8 -42.1 C +96.7 CO 2 -183 C -119 C

C3H8 only

Which of the following nonpolar molecules has the highest boiling point?

CS2

Given the following two half-reactions, determine which overall reaction is spontaneous and calculate its standard cell potential.Cd2+(aq) + 2 e- Cd(s) E = -1.21 VSn2+(aq) + 2 e- Sn(s) E = -0.14 V

Cd(s) + Sn2+(aq) Cd2+(aq) + Sn(s) = +1.07 V

Arrange Cl2, ICl, and Br2 in order from lowest to highest boiling point.

Cl2 < Br2 < IC

Use the standard reduction potentials below to determine which element or ion is the best reducing agent.Pd2+(aq) + 2 e- Pd(s) E = +0.90 VSn2+(aq) + 2 e- Sn(s) E = -0.14 VCr2+(aq) + 2 e- Cr(s) E = -0.91 V

Cr(s)

Assuming the following reaction proceeds in the forward direction,Ni2+(aq) + Cr(s) Ni(s) + Cr2+(aq)

Cr(s) is oxidized and Ni2+(aq) is reduced.

Place the following cations in order from the lowest to the highest hydration energy.

Cs+ < K+ < Ca2+

Which of the following equations is a correct form of the Nernst equation?

E = E - ( RT/nF) ln Q

Consider the following half-reactions:F2(g) + 2 e- 2 F-(aq) E = +2.87 VCu2+(aq) + 2 e- Cu(s) E = +0.34 VSn2+(aq) + 2 e- Sn(s) E = -0.14 VAl3+(aq) + 3 e- Al(s) E = -1.66 VNa+(aq) + e- Na(s) E = -2.71 VWhich of the above elements or ions will oxidize Sn(s)?

F2(g) and Cu2+(aq)

When a real gas is compressed from low pressure to a higher pressure at constant high pressure, its temperature increases. The system is closed, but not insulated (heat can go in or out). Predict the signs of of H and S after the interal pressure equalizes the external pressure.

H < 0 and S < 0

Predict the signs of H, S, and G for the evaporation of water 25 C.

H > 0, S > 0, G > 0

Which of the following thermodynamic quantities are state functions: heat (q), work (w), enthalpy change (H), and internal energy change (E)?

H and E

Arrange H2O, H2S, and H2Se in order from lowest to highest boiling point.

H2S < H2Se < H2O

As pure molecular solids, which of the following exhibits dipole-dipole intermolecular forces: HBr, NBr3, SBr2, and CBr4?

HBr, NBr3, and SBr2

Place the following cations in order from the lowest to the highest hydration enthalpy: K+, Ca2+, and Mg2+.

K+ < Ca2+ < Mg2+

Given the initial rate data for the reaction A + B C, determine the rate expression for the reaction.[A], M [B], M [C]/t (initial) M/s0.25 0.10 2.16 10-30.25 0.25 5.40 10-30.40 0.10 5.53 10-3

Rate = 0.35 M-2s-1[A]2[B]

Place the following gases in order of increasing average velocity at 325 K: Ar, Ne, N2, and SO2.

SO2 < Ar < N2 < Ne

Which of the following chemical equations does not correspond to a standard molar enthalpy of formation? (l) means (liquid)

SO2(g) + 1/2 O2(g) SO3(g)

The combustion of gasoline to propel a car is an example of

The conversion of chemical potential energy to mechanical energy.

If the volume of a confined gas is quadrupled while its temperature remains constant, what change will be observed?

The pressure of the gas will decrease to 1/4 its original value.

Which of the statements concerning relative rates of reaction is correct for the decomposition of dinitrogen pentaoxide?2 N2O5(g) 4 NO2(g) + O2(g)

The rate of disappearance of N2O5 is twice the rate of appearance of O2.

Given the initial rate data for the reaction A + B C, determine the order of the reaction with respect to each reactant.[A], M [B], M [C]/t (initial) M/s0.10 0.20 6.80 10-60.10 0.40 2.72 10-50.20 0.40 5.44 10-5

The reaction is first-order with respect to A and second-order with respect to B.

What is the correct cell notation for a voltaic cell based on the reaction below?Ni2+(aq) + Zn(s) Ni(s) + Zn2+(aq)

Zn(s) Zn2+(aq) Ni2+(aq) Ni(s)

In the following reaction,2 Fe3+(aq) + Zn(s) 2 Fe2+(aq) + Zn2+(aq)

Zn(s) is the reducing agent and Fe3+(aq) is the oxidizing agent.

What intermolecular force or bond is primarily responsible for the solubility of H2S in water?

dipole-dipole force

List all the intermolecular forces present in pure acetone.

dipole-dipole force and induced dipole/induced dipole force

Which of the following molecules is expected to form hydrogen bonds in the pure liquid or solid phase: ethanol (CH3CH2OH), acetic acid (CH3CO2H), acetaldehyde (CH3CHO), and dimethyl ether (CH3OCH3)?

ethanol and acetic acid

The boiling points of some group 7A hydrides are tabulated below.gas b.p. (C)NH3 -33PH3 -88AsH3 -62Which intermolecular force or bond is responsible for the high boiling point of NH3 relative to PH3 and AsH3?

hydrogen bonding

The second law of thermodynamics states that

in a spontaneous process, the entropy of the universe increases.

For the reaction R products, which of the following equations corresponds to the integrated expression for a first-order decomposition reaction?

ln = -kt

Avogadro's hypothesis states that equal volumes of gases under the same conditions of temperature and pressure have equal ____.

numbers of particles

If a cube of ice at 0 C is placed outside on a warm summer day, the ice will melt spontaneously. What are the signs of rH, rS, and rG for this process?

rH > 0, rS > 0, rG < 0

A Faraday, F, 96500, is defined as

the charge, in coulombs, carried by one mole of electrons.

Which of the following processes involves a DECREASE in entropy?

the condensation of steam to liquid water

Normal boiling point is defined as

the temperature at which the vapor pressure of a liquid equals 1 atm.

Calculate the work, E and H (in J) if a gas is heated with 100 cal and expands its volume by 2L under 1 atm of constant pressure? 1atm.L = 101 Joules

w = -202J, E = 216J, H= 418J