Question 1

For gaseous hydrogen atoms at 298 K is +217.kJ.mol-1 ,the standard enthalpy of formation can be best written as:

Accepted Answer

A)  2 H(g)  →\rightarrow→  H2(g) 
B)  ½H2(g)  →\rightarrow→  H(g) 
C)  H2(g)  →\rightarrow→  2 H(g) 
D)  2 H2(g)  →\rightarrow→  4 H(g) 
E)  H(g)  →\rightarrow→  ½H2(g)  F) A) and D)
G) B) and E)

Question 2

Calculate the change in internal energy when 2.50 kJ of energy is transferred as heat to 1.50 mol BF3 at 298 K and 1 atm at constant volume.

Accepted Answer

A)  +1.00 kJ
B)  +2.50 kJ
C)  (-1.50 kJ) 
D)  (-2.50 kJ) 
E)  +1.50 kJF) A) and C)
G) None of the above

Question 3

All bond enthalpies are positive.

Accepted Answer

A) True 
 B)False

Question 4

At constant pressure and temperature,which of the following statements is true for the reaction: 
N2O5(s)  →\rightarrow→ 2NO2(g) + ½O2(g) , Δ\DeltaΔ Hr = 109.5 kJ.mol-1  at 298 K.

Accepted Answer

A)  ( Δ\DeltaΔ H is independent of the physical states of the reactants.) 
B)  ( Δ\DeltaΔ H =  Δ\DeltaΔ U) 
C)  w = 0
D)  ( Δ\DeltaΔ H Δ\DeltaΔ U) 
E)  ( Δ\DeltaΔ H >  Δ\DeltaΔ U)  F) None of the above
G) C) and E)

Question 5

Work is reported in joules; and 1 joule = ____________

Accepted Answer

1 kg.m<sup...

Question 6

If 2.00 mol of an ideal gas at 300 K and 3.00 atm expands from 6.00 L to 18.00 L and has a final pressure of 1.20 atm,isothermally and reversibly,which of the following is correct?

Accepted Answer

A)  w = -5.48 kJ,q = +5.48 kJ, Δ\DeltaΔ U = 0
B)  w = -3.65 kJ,q = +3.65 kJ, Δ\DeltaΔ U = 0
C)  w = +3.65 kJ,q = +3.65 kJ, Δ\DeltaΔ U = +7.30 kJ
D)  w = -5.48 kJ,q = -5.48 kJ, Δ\DeltaΔ U = -11.0 kJ
E)  w = +5.48 kJ,q = +5.48 kJ, Δ\DeltaΔ U = +11.0 kJ F) A) and E)
G) C) and E)

Question 7

A CD player and its battery together do 500 kJ of work.The battery also releases 250 kJ of energy as heat,and the CD player releases 50 kJ as heat due to friction from spinning.What is the change in internal energy of the system,with the system regarded as the battery alone? Assume that the battery does 500 kJ of work on the CD player,which then does the same amount of work on the surroundings.

Accepted Answer

A)  +200 kJ
B)  (-800 kJ) 
C)  (-750 kJ) 
D)  (-50 kJ) 
E)  (-700 kJ) F) None of the above
G) B) and D)

Question 8

Determine Δ\DeltaΔ Hf ∘\circ∘ (HCl(g) ) from the following data. H-Cl bond enthalpy = +431 kJ.mol-1 
 Δ\DeltaΔ Hf ∘\circ∘ (H(g) ) = +217.9 kJ.mol-1 
 Δ\DeltaΔ Hf ∘\circ∘ (Cl(g) ) = +121.4 kJ.mol-1

Accepted Answer

A)  +92 kJ.mol-1 
B)  (-261 kJ.mol-1 ) 
C)  (-431 kJ.mol-1 ) 
D)  +431 kJ.mol-1 
E)  (-92 kJ.mol-1 )  F) D) and E)
G) C) and D)

Question 9

For Br2(l),the standard enthalpy of formation is ______________________ (positive/ negative/ zero).

Accepted Answer

Question 10

A reaction known to release 2.00 kJ of heat takes place in a calorimeter containing 0.200 L of solution and the temperature rose by 4.46 ∘\circ∘ C.When 100 mL of nitric acid and 100 mL of sodium hydroxide were mixed in the same calorimeter,the temperature rose 2.0 ∘\circ∘ C.What is the heat output for the neutralization reaction?

Accepted Answer

A)  0.0186 kJ-1.( ∘\circ∘ 
C)  -1 
B)  0.448 kJ-1.( ∘\circ∘ 
C)  -1 
C)  0.816 kJ-1.( ∘\circ∘ 
C)  -1 
D)  17.9 kJ-1.( ∘\circ∘ 
C)  -1 
E)  0.901 kJ-1.( ∘\circ∘ 
C)  -1  F) B) and D)
G) A) and E)

Question 11

What mass of propane,C3H8(g) ,must be burned to supply 2580 kJ of heat? The standard enthalpy of combustion of propane at 298 K is -2220 kJ.mol-1

Accepted Answer

A)  25.6 g
B)  51.2 g
C)  102 g
D)  75.9 g
E)  37.9 gF) B) and C)
G) A) and B)

Question 12

for the reaction
N2O5(s)$\rightarrow$  2NO2(g)+ ½O2(g),$\Delta$Hr = 109.5 kJ.mol-1  at 298 K
at constant temperature and pressure,$\Delta$H > $\Delta$U.

Accepted Answer

A) True 
 B)False

Question 13

A closed system can exchange energy with the surroundings.

Accepted Answer

A) True 
 B)False

Question 14

A system had 150 kJ of work done on it and its internal energy increased by 60 kJ.How much energy did the system gain or lose as heat?

Accepted Answer

A)  The system lost 90 kJ of energy as heat.
B)  The system lost 210 kJ of energy as heat.
C)  The system gained 60 kJ of energy as heat.
D)  The system gained 90 kJ of energy as heat.
E)  The system gained 210 kJ of energy as heat.F) B) and D)
G) A) and E)

Question 15

The formation of solid calcium oxide from a gas of its ions is an exothermic process and is equal to the reverse of the lattice enthalpy.

Accepted Answer

A) True 
 B)False

Question 16

Which of the following is not a state function?

Accepted Answer

A)  H
B)  T
C)  U
D)  S
E)  None; they are all state functions.F) All of the above
G) A) and D)

Question 17

When a gas expands into a vacuum,w = 0.

Accepted Answer

A) True 
 B)False

Question 18

The standard enthalpy of formation of NaCl(s) is -411 kJ/mol.In a Born-Haber cycle for the formation of NaCl(s) ,which enthalpy change(s) is/are endothermic?

Accepted Answer

A)  the lattice enthalpy of NaCl(s) 
B)  the electron affinity of chlorine
C)  the reverse of the lattice enthalpy of NaCl(s) 
D)  All of the enthalpy changes are endothermic except for the standard enthalpy of formation of NaCl(s) .E) A) and B)
F) A) and C)

Question 19

An isothermal change is one that occurs at a constant temperature.

Accepted Answer

A) True 
 B)False

Question 20

Calculate the change in internal energy when 2.50 kJ of energy is transferred as heat to 1.50 mol N2 at 298 K and 1 atm at constant volume.

Accepted Answer

A)  (-2.50 kJ) 
B)  +2.50 kJ
C)  +1.00 kJ
D)  (-1.50 kJ) 
E)  +1.50 kJF) A) and D)
G) A) and E)

Exam 8: Thermodynamics: The First Law

Which of the following is not a state function?

Correct Answer
verified

At constant pressure and temperature,which of the following statements is true for the reaction: N₂O₅(s) $\rightarrow$ 2NO₂(g) + ½O₂(g) , $\Delta$ H_r = 109.5 kJ.mol^-1 at 298 K.

Correct Answer
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All bond enthalpies are positive.

Correct Answer
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For gaseous hydrogen atoms at 298 K is +217.kJ.mol^-1,the standard enthalpy of formation can be best written as:

Correct Answer
verified

If 2.00 mol of an ideal gas at 300 K and 3.00 atm expands from 6.00 L to 18.00 L and has a final pressure of 1.20 atm,isothermally and reversibly,which of the following is correct?

Correct Answer
verified

The standard enthalpy of formation of NaCl(s) is -411 kJ/mol.In a Born-Haber cycle for the formation of NaCl(s) ,which enthalpy change(s) is/are endothermic?

Correct Answer
verified

What mass of propane,C₃H₈(g) ,must be burned to supply 2580 kJ of heat? The standard enthalpy of combustion of propane at 298 K is -2220 kJ.mol^-1

Correct Answer
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When a gas expands into a vacuum,w = 0.

Correct Answer
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Correct Answer
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Determine $\Delta$ H_f^$\circ$(HCl(g) ) from the following data. H-Cl bond enthalpy = +431 kJ.mol^-1 $\Delta$ H_f^$\circ$(H(g) ) = +217.9 kJ.mol^-1 $\Delta$ H_f^$\circ$(Cl(g) ) = +121.4 kJ.mol^-1

Correct Answer
verified

For Br₂(l),the standard enthalpy of formation is ______________________ (positive/ negative/ zero).

Correct Answer
verified

The formation of solid calcium oxide from a gas of its ions is an exothermic process and is equal to the reverse of the lattice enthalpy.

Correct Answer
verified

An isothermal change is one that occurs at a constant temperature.

Correct Answer
verified

Correct Answer
verified

Calculate the change in internal energy when 2.50 kJ of energy is transferred as heat to 1.50 mol BF₃ at 298 K and 1 atm at constant volume.

Correct Answer
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Calculate the change in internal energy when 2.50 kJ of energy is transferred as heat to 1.50 mol N₂ at 298 K and 1 atm at constant volume.

Correct Answer
verified

A closed system can exchange energy with the surroundings.

Correct Answer
verified

A system had 150 kJ of work done on it and its internal energy increased by 60 kJ.How much energy did the system gain or lose as heat?

Correct Answer
verified

Work is reported in joules; and 1 joule = ____________

Correct Answer
verified
1 kg.m
View Answer

for the reaction N₂O₅(s) $\rightarrow$ 2NO₂(g)+ ½O₂(g), $\Delta$ H_r = 109.5 kJ.mol^-1 at 298 K at constant temperature and pressure, $\Delta$ H > $\Delta$ U.

Correct Answer
verified

Exam 8: Thermodynamics: The First Law

Which of the following is not a state function?

Correct AnswerverifiedShow Answer

At constant pressure and temperature,which of the following statements is true for the reaction: N2O5(s) →\rightarrow→ 2NO2(g) + ½O2(g) , Δ\DeltaΔ Hr = 109.5 kJ.mol-1 at 298 K.

Correct AnswerverifiedShow Answer

All bond enthalpies are positive.

Correct AnswerverifiedShow Answer

For gaseous hydrogen atoms at 298 K is +217.kJ.mol-1 ,the standard enthalpy of formation can be best written as:

Correct AnswerverifiedShow Answer

If 2.00 mol of an ideal gas at 300 K and 3.00 atm expands from 6.00 L to 18.00 L and has a final pressure of 1.20 atm,isothermally and reversibly,which of the following is correct?

Correct AnswerverifiedShow Answer

The standard enthalpy of formation of NaCl(s) is -411 kJ/mol.In a Born-Haber cycle for the formation of NaCl(s) ,which enthalpy change(s) is/are endothermic?

Correct AnswerverifiedShow Answer

What mass of propane,C3H8(g) ,must be burned to supply 2580 kJ of heat? The standard enthalpy of combustion of propane at 298 K is -2220 kJ.mol-1

Correct AnswerverifiedShow Answer

When a gas expands into a vacuum,w = 0.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Determine Δ\DeltaΔ Hf ∘\circ∘ (HCl(g) ) from the following data. H-Cl bond enthalpy = +431 kJ.mol-1 Δ\DeltaΔ Hf ∘\circ∘ (H(g) ) = +217.9 kJ.mol-1 Δ\DeltaΔ Hf ∘\circ∘ (Cl(g) ) = +121.4 kJ.mol-1

Correct AnswerverifiedShow Answer

For Br2(l),the standard enthalpy of formation is ______________________ (positive/ negative/ zero).

Correct AnswerverifiedShow Answer

The formation of solid calcium oxide from a gas of its ions is an exothermic process and is equal to the reverse of the lattice enthalpy.

Correct AnswerverifiedShow Answer

An isothermal change is one that occurs at a constant temperature.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Calculate the change in internal energy when 2.50 kJ of energy is transferred as heat to 1.50 mol BF3 at 298 K and 1 atm at constant volume.

Correct AnswerverifiedShow Answer

Calculate the change in internal energy when 2.50 kJ of energy is transferred as heat to 1.50 mol N2 at 298 K and 1 atm at constant volume.

Correct AnswerverifiedShow Answer

A closed system can exchange energy with the surroundings.

Correct AnswerverifiedShow Answer

A system had 150 kJ of work done on it and its internal energy increased by 60 kJ.How much energy did the system gain or lose as heat?

Correct AnswerverifiedShow Answer

Work is reported in joules; and 1 joule = ____________

Correct Answerverified1 kg.mView AnswerShow Answer

for the reaction N2O5(s) →\rightarrow→ 2NO2(g)+ ½O2(g), Δ\DeltaΔ Hr = 109.5 kJ.mol-1 at 298 K at constant temperature and pressure, Δ\DeltaΔ H > Δ\DeltaΔ U.

Correct AnswerverifiedShow Answer

Correct Answer
verified

At constant pressure and temperature,which of the following statements is true for the reaction: N₂O₅(s) $\rightarrow$ 2NO₂(g) + ½O₂(g) , $\Delta$ H_r = 109.5 kJ.mol^-1 at 298 K.

Correct Answer
verified

Correct Answer
verified

For gaseous hydrogen atoms at 298 K is +217.kJ.mol^-1,the standard enthalpy of formation can be best written as:

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

What mass of propane,C₃H₈(g) ,must be burned to supply 2580 kJ of heat? The standard enthalpy of combustion of propane at 298 K is -2220 kJ.mol^-1

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Determine $\Delta$ H_f^$\circ$(HCl(g) ) from the following data. H-Cl bond enthalpy = +431 kJ.mol^-1 $\Delta$ H_f^$\circ$(H(g) ) = +217.9 kJ.mol^-1 $\Delta$ H_f^$\circ$(Cl(g) ) = +121.4 kJ.mol^-1

Correct Answer
verified

For Br₂(l),the standard enthalpy of formation is ______________________ (positive/ negative/ zero).

Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
verified

Calculate the change in internal energy when 2.50 kJ of energy is transferred as heat to 1.50 mol BF₃ at 298 K and 1 atm at constant volume.

Correct Answer
verified

Calculate the change in internal energy when 2.50 kJ of energy is transferred as heat to 1.50 mol N₂ at 298 K and 1 atm at constant volume.

Correct Answer
verified

Correct Answer
verified

Correct Answer
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Correct Answer
verified
1 kg.m
View Answer

for the reaction N₂O₅(s) $\rightarrow$ 2NO₂(g)+ ½O₂(g), $\Delta$ H_r = 109.5 kJ.mol^-1 at 298 K at constant temperature and pressure, $\Delta$ H > $\Delta$ U.

Correct Answer
verified