Question 1

What is the total motional contribution to the molar internal energy of gaseous BF3?

Accepted Answer

A) RT 
B) 3.5RT 
C) 3RT 
D) 1.5RT 
E) 2.5RT 
A) RT 
B) 3.5RT 
C) 3RT 
D) 1.5RT 
E) 2.5RT

Question 2

The standard enthalpy of formation of gaseous water is -241.82 kJ.mol-1 at 298 K.Estimate this value at 370 K.The molar heat capacities of hydrogen,oxygen,and gaseous water are 28.82,29.36,and 33.58 J.K-1 .mol-1

Accepted Answer

A) (-241.82 kJ.mol-1 ) 
B) (-243.25 kJ.mol-1 ) 
C) (-242.54 kJ.mol-1 ) 
D) (-240.39 kJ.mol-1 ) 
E) (-241.10 kJ.mol-1 ) 
A) (-241.82 kJ.mol-1 ) 
B) (-243.25 kJ.mol-1 ) 
C) (-242.54 kJ.mol-1 ) 
D) (-240.39 kJ.mol-1 ) 
E) (-241.10 kJ.mol-1 )

Question 3

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 CD player 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) -550 kJ 
B) (-50 kJ) 
C) (-950 kJ) 
D) (-800 kJ) 
E) +450 kJ 
A) -550 kJ 
B) (-50 kJ) 
C) (-950 kJ) 
D) (-800 kJ) 
E) +450 kJ

Question 4

Calculate the standard enthalpy of vaporization of liquid bromine if the standard enthalpy of sublimation of solid bromine is +40.1 kJ.mol-1 and the standard enthalpy of fusion of solid bromine is +10.6 kJ.mol-1.

Accepted Answer

A) (-50.7 kJ.mol-1) 
B) (-29.5 kJ.mol-1) 
C) (+50.7 kJ.mol-1) 
D) (+14.8 kJ.mol-1) 
E) (+29.5 kJ.mol-1) 
A) (-50.7 kJ.mol-1) 
B) (-29.5 kJ.mol-1) 
C) (+50.7 kJ.mol-1) 
D) (+14.8 kJ.mol-1) 
E) (+29.5 kJ.mol-1)

Question 5

Calculate the standard reaction enthalpy for the following 
reaction: 
2NO2(g)$\rightarrow$ 2NO(g)+ O2(g)
From the standard reaction enthalpies of
N2(g)+ O2 $\rightarrow$ 2NO(g)
$\Delta$H° = +180.5 kJ.mol-1 
2NO2(g)$\rightarrow$ N2(g)+ 2O2(g)
$\Delta$H° = -66.4 kJ.mol-1

Accepted Answer

A) (-114.1 kJ.mol-1 ) 
B) (-246.9 kJ.mol-1 ) 
C) (+114.1 kJ.mol-1 ) 
D) (-294.6 kJ.mol-1 ) 
E) (+246.9 kJ.mol-1 ) 
A) (-114.1 kJ.mol-1 ) 
B) (-246.9 kJ.mol-1 ) 
C) (+114.1 kJ.mol-1 ) 
D) (-294.6 kJ.mol-1 ) 
E) (+246.9 kJ.mol-1 )

Question 6

What is the total motional contribution to the molar internal energy of gaseous H2O at 25S1U1P1$\circ$S1S1P0C?

Accepted Answer

A) 6.19 kJ.mol-1  
B) 7.43 kJ.mol-1  
C) 3.72 kJ.mol-1  
D) 12.4 kJ.mol-1  
E) 2.48 kJ.mol-1  
A) 6.19 kJ.mol-1  
B) 7.43 kJ.mol-1  
C) 3.72 kJ.mol-1  
D) 12.4 kJ.mol-1  
E) 2.48 kJ.mol-1

Question 7

The standard enthalpy of formation of ammonia gas is -46.11 kJ.mol-1  at 298 K.What is the standard reaction enthalpy for the Haber process at 500S1U1P1$\circ$S1S1P0C? The molar heat capacities of nitrogen,hydrogen,and ammonia are 29.12,28.82,and 35.06 kJ.mol-1 respectively.

Accepted Answer

A) (-97.65 kJ.mol-1 ) 
B) (-113.81 kJ.mol-1 ) 
C) (-56.91 kJ.mol-1 ) 
D) (-92.22 kJ.mol-1 ) 
E) (-103.09 kJ.mol-1 ) 
A) (-97.65 kJ.mol-1 ) 
B) (-113.81 kJ.mol-1 ) 
C) (-56.91 kJ.mol-1 ) 
D) (-92.22 kJ.mol-1 ) 
E) (-103.09 kJ.mol-1 )

Question 8

Give $\Delta$Hr values for each of the following reactions from the information below.

$\Delta$HfS1U1P1$\circ$S1S1P0(HCl(g))= -92.31 kJ.mol-1 
H-Cl bond enthalpy = +431 kJ.mol-1 
O-H bond enthalpy = +463 kJ.mol-1 
$\Delta$HfS1U1P1$\circ$S1S1P0(H2O(g))= -241.8 kJ.mol-1
(a)2H(g)+ O(g)$\rightarrow$H2O(g)
(b)H2(g)+ Cl2(g)$\rightarrow$ 2HCl(g)
(c)H(g)+ Cl(g)$\rightarrow$ HCl(g)

Accepted Answer

(a)-926 kJ.mol<sup>-

Question 9

An isolated system can exchange energy and small particles with the surroundings.

Accepted Answer

A) True 
 B)False

Question 10

The lattice enthalpy of calcium oxide is the energy change for the reaction

Accepted Answer

A) CaO(s)$\rightarrow$  Ca(g)+ O(g) 
B) CaO(s)$\rightarrow$  Ca(g)+ ½O2(g) 
C) Ca(g)+ O(g)$\rightarrow$  CaO(g) 
D) CaO(s)$\rightarrow$  Ca2+(g)+ O2-(g) 
E) Ca(s)+ ½O2(g)$\rightarrow$  CaO(s) 
A) CaO(s)$\rightarrow$  Ca(g)+ O(g) 
B) CaO(s)$\rightarrow$  Ca(g)+ ½O2(g) 
C) Ca(g)+ O(g)$\rightarrow$  CaO(g) 
D) CaO(s)$\rightarrow$  Ca2+(g)+ O2-(g) 
E) Ca(s)+ ½O2(g)$\rightarrow$  CaO(s)

Question 11

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 pressure.

Accepted Answer

A) +1.56 kJ 
B) +2.50 kJ 
C) 1.87 kJ 
D) (-2.50 kJ) 
E) (-1.87 kJ) 
A) +1.56 kJ 
B) +2.50 kJ 
C) 1.87 kJ 
D) (-2.50 kJ) 
E) (-1.87 kJ)

Question 12

Calculate the standard enthalpy of formation of potassium chloride given the following enthalpy data.

Accepted Answer

-437 kJ.mo

Question 13

The combustion of 1 mole of ethanol,C2H5OH(l),to produce carbon dioxide and gaseous water has $\Delta$Hr = -1235 kJ.mol-1  at 298 K.What is the change in internal energy for this reaction?

Accepted Answer

A) (-1237 kJ.mol-1 ) 
B) (-1240 kJ.mol-1 ) 
C) (-1230 kJ.mol-1 ) 
D) (-1247 kJ.mol-1 ) 
E) (-1223 kJ.mol-1 ) 
A) (-1237 kJ.mol-1 ) 
B) (-1240 kJ.mol-1 ) 
C) (-1230 kJ.mol-1 ) 
D) (-1247 kJ.mol-1 ) 
E) (-1223 kJ.mol-1 )

Question 14

The combustion of one mole of octane,C8H18(l),in a bomb calorimeter released 5460 kJ of heat at 298 K.The products of the reaction are carbon dioxide and liquid water.What is the enthalpy change for this reaction?

Accepted Answer

A) +5471 kJ.mol-1  
B) (-5460 kJ.mol-1 ) 
C) (-5471 kJ.mol-1 ) 
D) (-5449 kJ.mol-1 ) 
E) +5460 kJ.mol-1  
A) +5471 kJ.mol-1  
B) (-5460 kJ.mol-1 ) 
C) (-5471 kJ.mol-1 ) 
D) (-5449 kJ.mol-1 ) 
E) +5460 kJ.mol-1

What is the total motional contribution to the molar internal energy of gaseous BF₃?

The standard enthalpy of formation of gaseous water is -241.82 kJ.mol^-1 at 298 K.Estimate this value at 370 K.The molar heat capacities of hydrogen,oxygen,and gaseous water are 28.82,29.36,and 33.58 J.K^-1.mol^-1

Calculate the standard enthalpy of vaporization of liquid bromine if the standard enthalpy of sublimation of solid bromine is +40.1 kJ.mol^-1 and the standard enthalpy of fusion of solid bromine is +10.6 kJ.mol^-1.

Calculate the standard reaction enthalpy for the following reaction: 2NO₂(g) $\rightarrow$ 2NO(g)+ O₂(g) From the standard reaction enthalpies of N₂(g)+ O₂ $\rightarrow$ 2NO(g) $\Delta$ H° = +180.5 kJ.mol^-1 2NO₂(g) $\rightarrow$ N₂(g)+ 2O₂(g) $\Delta$ H° = -66.4 kJ.mol^-1

What is the total motional contribution to the molar internal energy of gaseous H₂O at 25^$\circ$C?

The standard enthalpy of formation of ammonia gas is -46.11 kJ.mol^-1 at 298 K.What is the standard reaction enthalpy for the Haber process at 500^$\circ$C? The molar heat capacities of nitrogen,hydrogen,and ammonia are 29.12,28.82,and 35.06 kJ.mol^-1respectively.

An isolated system can exchange energy and small particles with the surroundings.

The lattice enthalpy of calcium oxide is the energy change for the reaction

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 pressure.

Calculate the standard enthalpy of formation of potassium chloride given the following enthalpy data.

The combustion of 1 mole of ethanol,C₂H₅OH(l),to produce carbon dioxide and gaseous water has $\Delta$ H_r = -1235 kJ.mol^-1 at 298 K.What is the change in internal energy for this reaction?

The combustion of one mole of octane,C₈H₁₈(l),in a bomb calorimeter released 5460 kJ of heat at 298 K.The products of the reaction are carbon dioxide and liquid water.What is the enthalpy change for this reaction?

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Exam 8: Thermodynamics: The First Law

What is the total motional contribution to the molar internal energy of gaseous BF3?

The standard enthalpy of formation of gaseous water is -241.82 kJ.mol-1 at 298 K.Estimate this value at 370 K.The molar heat capacities of hydrogen,oxygen,and gaseous water are 28.82,29.36,and 33.58 J.K-1 .mol-1

Calculate the standard enthalpy of vaporization of liquid bromine if the standard enthalpy of sublimation of solid bromine is +40.1 kJ.mol-1 and the standard enthalpy of fusion of solid bromine is +10.6 kJ.mol-1.

Calculate the standard reaction enthalpy for the following reaction: 2NO2(g) →\rightarrow→ 2NO(g)+ O2(g) From the standard reaction enthalpies of N2(g)+ O2 →\rightarrow→ 2NO(g) Δ\DeltaΔ H° = +180.5 kJ.mol-1 2NO2(g) →\rightarrow→ N2(g)+ 2O2(g) Δ\DeltaΔ H° = -66.4 kJ.mol-1

What is the total motional contribution to the molar internal energy of gaseous H2O at 25 ∘\circ∘ C?

The standard enthalpy of formation of ammonia gas is -46.11 kJ.mol-1 at 298 K.What is the standard reaction enthalpy for the Haber process at 500 ∘\circ∘ C? The molar heat capacities of nitrogen,hydrogen,and ammonia are 29.12,28.82,and 35.06 kJ.mol-1 respectively.

An isolated system can exchange energy and small particles with the surroundings.

The lattice enthalpy of calcium oxide is the energy change for the reaction

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 pressure.

Calculate the standard enthalpy of formation of potassium chloride given the following enthalpy data.

The combustion of 1 mole of ethanol,C2H5OH(l),to produce carbon dioxide and gaseous water has Δ\DeltaΔ Hr = -1235 kJ.mol-1 at 298 K.What is the change in internal energy for this reaction?

The combustion of one mole of octane,C8H18(l),in a bomb calorimeter released 5460 kJ of heat at 298 K.The products of the reaction are carbon dioxide and liquid water.What is the enthalpy change for this reaction?

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What is the total motional contribution to the molar internal energy of gaseous BF₃?

The standard enthalpy of formation of gaseous water is -241.82 kJ.mol^-1 at 298 K.Estimate this value at 370 K.The molar heat capacities of hydrogen,oxygen,and gaseous water are 28.82,29.36,and 33.58 J.K^-1.mol^-1

Calculate the standard enthalpy of vaporization of liquid bromine if the standard enthalpy of sublimation of solid bromine is +40.1 kJ.mol^-1 and the standard enthalpy of fusion of solid bromine is +10.6 kJ.mol^-1.

Calculate the standard reaction enthalpy for the following reaction: 2NO₂(g) $\rightarrow$ 2NO(g)+ O₂(g) From the standard reaction enthalpies of N₂(g)+ O₂ $\rightarrow$ 2NO(g) $\Delta$ H° = +180.5 kJ.mol^-1 2NO₂(g) $\rightarrow$ N₂(g)+ 2O₂(g) $\Delta$ H° = -66.4 kJ.mol^-1

What is the total motional contribution to the molar internal energy of gaseous H₂O at 25^$\circ$C?

The standard enthalpy of formation of ammonia gas is -46.11 kJ.mol^-1 at 298 K.What is the standard reaction enthalpy for the Haber process at 500^$\circ$C? The molar heat capacities of nitrogen,hydrogen,and ammonia are 29.12,28.82,and 35.06 kJ.mol^-1respectively.

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 pressure.

The combustion of 1 mole of ethanol,C₂H₅OH(l),to produce carbon dioxide and gaseous water has $\Delta$ H_r = -1235 kJ.mol^-1 at 298 K.What is the change in internal energy for this reaction?

The combustion of one mole of octane,C₈H₁₈(l),in a bomb calorimeter released 5460 kJ of heat at 298 K.The products of the reaction are carbon dioxide and liquid water.What is the enthalpy change for this reaction?