Question 1

Calculate the standard enthalpy of combustion of butane, C4H10(g),
at 298 K from standard enthalpy of formation data.

Accepted Answer

-2877.04 k

Question 2

For most reactions,the value of $\Delta$U is very close to that for $\Delta$H

Accepted Answer

A) True 
 B)False

Question 3

The entropy of fusion of water is +22.0 J.K-1.mol-1 > and the enthalpy of fusion of water is +6.01 J.K-1.mol-1 at 0$\omicron$C.At 0$\omicron$C, $\Delta$Stotal for the melting of ice is

Accepted Answer

A) -6010 J.K-1.mol-1  
B)  0. 
C)  -22.0 J.K-1.mol-1  
D)  +6010 J.K-1.mol-1  
E)  +22.0 J.K-1.mol-1  
A) -6010 J.K-1.mol-1  
B)  0. 
C)  -22.0 J.K-1.mol-1  
D)  +6010 J.K-1.mol-1  
E)  +22.0 J.K-1.mol-1

Question 4

Calculate the entropy of vaporization of water at 25$\omicron$C and 1 bar.
The molar heat capacities of the liquid and gas are 75 and 34 J·K-1·mol-1, respectively.The molar enthalpy of vaporization of water at its normal boiling point is 40.7 kJ·mol-1.

Accepted Answer

+118 J·K^-

Question 5

When calculating the entropy change as a result of transferring heat reversibly to or from a system,the temperature must be constant.

Accepted Answer

A) True 
 B)False

Question 6

Calculate the standard reaction enthalpy for the following reaction:
$\begin{array}{ll}2 \mathrm{NO}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{NO}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{~g})\
\text { From the standard reaction enthalpies of }\
\mathrm{N}_{2}(\mathrm{~g})+\mathrm{O}_{2} \rightarrow 2 \mathrm{NO}(\mathrm{g}) & \Delta H^{\circ}=+180.5 \mathrm{~kJ} \cdot \mathrm{mol}^{-1} \
2 \mathrm{NO}_{2}(\mathrm{~g}) \rightarrow \mathrm{N}_{2}(\mathrm{~g})+2 \mathrm{O}_{2}(\mathrm{~g}) & \Delta H^{\circ}=-66.4 \mathrm{~kJ} \cdot \mathrm{mol}^{-1}
\end{array}$

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 7

Consider the compounds
PCl5(g),HCN(g),CuO(s),NO(g),NH3(g),And SO2(g).
Which compound will have approximately the same stability with respect to its elements if the temperature is raised?

Accepted Answer

A)  CuO(s) 
B)  NO(g) 
C)  PCl5(g) 
D)  HCN(g) 
E)  NH3(g) 
A)  CuO(s) 
B)  NO(g) 
C)  PCl5(g) 
D)  HCN(g) 
E)  NH3(g)

Question 8

The molar heat capacity of Cu(s)
at 1 atm pressure has been measured over a range of temperatures from close to 0 K to 400 K.
Describe how you would obtain the standard molar entropy of Cu(s)
at 298 K.

Accepted Answer

Plot C_P/T versus T.Th

Question 9

The reaction CH3CH2CH2CH3(g)$\rightarrow$CH3CH(CH3)2(g),is exothermic.This reaction will be spontaneous at high temperatures.

Accepted Answer

A) True 
 B)False

Question 10

Predict the sign (+,-,0) of the entropy change when a glass of water reversibly loses 200 J of energy at 25°C.

Accepted Answer

The answer of Predict the sign (+,-,0) of the entropy...

Question 11

In the combustion of coal,C(s),the C=O bonds are stronger than the O=O bond.

Accepted Answer

A) True 
 B)False

Question 12

Draw a graph of the molar Gibbs free energy versus temperature for H2O(l)
and H2O(g).
(a)Explain the slopes of the 2 lines.
(b)At low temperatures,which phase is most stable?
(c)At high temperatures,which phase is more stable?

Accepted Answer

(a)Because the molar entropy of the gas

Question 13

Calculate the standard entropy of fusion of ethanol at its melting point, 159 K. The standard molar enthalpy of fusion of ethanol at its melting point is 5.02 kJ.mol-1.

Accepted Answer

A)  -5.02 kJ.K-1.mol-1  
B)  -31.6 J.K-1.mol-1  
C)  +5.02 J.K-1.mol-1  
D)  +31.6 J.K-1.mol-1  
E)  -44.0 J.K-1.mol-1  
A)  -5.02 kJ.K-1.mol-1  
B)  -31.6 J.K-1.mol-1  
C)  +5.02 J.K-1.mol-1  
D)  +31.6 J.K-1.mol-1  
E)  -44.0 J.K-1.mol-1

Question 14

In a system composed of nitrogen gas in a cylinder fitted with a piston, when 2.00 kJ of energy is transferred as heat at an external pressure of 2.00 atm,
The nitrogen gas expands from 2.00 to 5.00 L against this constant pressure.What is $\Delta$U for the process?

Accepted Answer

A)  -0.608 kJ 
B)  +1.39 kJ 
C)  +2.61 kJ 
D)  0 
E)  -2.61 kJ 
A)  -0.608 kJ 
B)  +1.39 kJ 
C)  +2.61 kJ 
D)  0 
E)  -2.61 kJ

Question 15

For the reaction CO2(aq) $\rightarrow$CO2(g),
$\Delta$Hr = 19.4 kJ.mol-1  at 298.At constant temperature and pressure,Which of the following statements is true?

Accepted Answer

A)  w = 0 
B) $\Delta$U = 2.48 kJ 
C)  $\Delta$H  $\Delta$U 
A)  w = 0 
B) $\Delta$U = 2.48 kJ 
C)  $\Delta$H  $\Delta$U

Question 16

The cooling of a hot metal is accompanied by an increase in entropy.

Accepted Answer

A) True 
 B)False

Question 17

For He(g,10 atm)$\rightarrow$ He(g,1 atm),is the entropy change positive or negative?

Accepted Answer

The answer of For He(g,10 atm)$\rightarrow$ He(g,1 atm),is the entropy...

Question 18

The reaction
2Cu(s)+ CO2(g)$\rightarrow$2CuO(s)+ C(s)
Is endothermic.Which of the following statements is true?

Accepted Answer

A)  The reaction is not spontaneous at any temperature. 
B)  The reaction is spontaneous at all temperatures. 
C)  It is impossible to determine if the reaction is spontaneous without calculations. 
D)  The reaction will be spontaneous only at low temperatures. 
E)  The reaction will be spontaneous only at high temperatures. 
A)  The reaction is not spontaneous at any temperature. 
B)  The reaction is spontaneous at all temperatures. 
C)  It is impossible to determine if the reaction is spontaneous without calculations. 
D)  The reaction will be spontaneous only at low temperatures. 
E)  The reaction will be spontaneous only at high temperatures.

Question 19

Match the values with the correct enthalpy change.
 $\begin{array}{ll}\text { Enthalpy }&\text { Value }\
\hline \Delta H_{\mathrm{f}}^{\circ}(\mathrm{C}(\mathrm{g})) & -1300 \mathrm{~kJ} \cdot \mathrm{mol}^{-1} \
\Delta H_{\mathrm{f}}^{\circ}(\mathrm{C}(\mathrm{s}),(\text { graphite })) & +717 \mathrm{~kJ} \cdot \mathrm{mol}^{-1} \
\Delta H_{\mathrm{c}}^{\circ}\left(\mathrm{C}_{2} \mathrm{H}_{2}(\mathrm{~g})\right) & +31 \mathrm{~kJ} \cdot \mathrm{mol}^{-1} \
\Delta H_{\mathrm{f}}^{\circ}\left(\mathrm{Br}_{2}(\mathrm{~g})\right) & 0
\end{array}$

Accepted Answer

The answer of Match the values with the correct enthalpy...

Question 20

A battery does 35 kJ of work driving an electric motor and 7 kJ of heat are released .What is the change in internal energy of the system?

Accepted Answer

A)  -35 kJ 
B)  +42 kJ 
C)  -42 kJ 
D)  -28 kJ 
E)  +28 kJ 
A)  -35 kJ 
B)  +42 kJ 
C)  -42 kJ 
D)  -28 kJ 
E)  +28 kJ

Calculate the standard enthalpy of combustion of butane, C₄H₁₀(g), at 298 K from standard enthalpy of formation data.

For most reactions,the value of $\Delta$ U is very close to that for $\Delta$ H

The entropy of fusion of water is +22.0 J.K^-¹.mol^-¹> and the enthalpy of fusion of water is +6.01 J.K^-¹.mol^-¹at 0^$\omicron$C.At 0^$\omicron$C, $\Delta$ S_total for the melting of ice is

Calculate the entropy of vaporization of water at 25^$\omicron$C and 1 bar. The molar heat capacities of the liquid and gas are 75 and 34 J·K^-¹·mol^-¹, respectively.The molar enthalpy of vaporization of water at its normal boiling point is 40.7 kJ·mol^-¹.

When calculating the entropy change as a result of transferring heat reversibly to or from a system,the temperature must be constant.

Calculate the standard reaction enthalpy for the following reaction: 2()\rightarrow2()+() From the standard reaction enthalpies of ()+\rightarrow2() \Delta=+180.5\cdot 2()\rightarrow()+2() \Delta=-66.4\cdot

Consider the compounds PCl₅(g),HCN(g),CuO(s),NO(g),NH₃(g),And SO₂(g). Which compound will have approximately the same stability with respect to its elements if the temperature is raised?

The molar heat capacity of Cu(s) at 1 atm pressure has been measured over a range of temperatures from close to 0 K to 400 K. Describe how you would obtain the standard molar entropy of Cu(s) at 298 K.

The reaction CH₃CH₂CH₂CH₃(g) $\rightarrow$ CH₃CH(CH₃)₂(g),is exothermic.This reaction will be spontaneous at high temperatures.

Predict the sign (+,-,0) of the entropy change when a glass of water reversibly loses 200 J of energy at 25°C.

In the combustion of coal,C(s),the C=O bonds are stronger than the O=O bond.

Draw a graph of the molar Gibbs free energy versus temperature for H₂O(l) and H₂O(g). (a)Explain the slopes of the 2 lines. (b)At low temperatures,which phase is most stable? (c)At high temperatures,which phase is more stable?

Calculate the standard entropy of fusion of ethanol at its melting point, 159 K. The standard molar enthalpy of fusion of ethanol at its melting point is 5.02 kJ.mol^-¹.

In a system composed of nitrogen gas in a cylinder fitted with a piston, when 2.00 kJ of energy is transferred as heat at an external pressure of 2.00 atm, The nitrogen gas expands from 2.00 to 5.00 L against this constant pressure.What is $\Delta$ U for the process?

For the reaction CO₂(aq) $\rightarrow$ CO₂(g), $\Delta$ H_r = 19.4 kJ.mol^-¹ at 298.At constant temperature and pressure,Which of the following statements is true?

The cooling of a hot metal is accompanied by an increase in entropy.

For He(g,10 atm) $\rightarrow$ He(g,1 atm),is the entropy change positive or negative?

The reaction 2Cu(s)+ CO₂(g) $\rightarrow$ 2CuO(s)+ C(s) Is endothermic.Which of the following statements is true?

Match the values with the correct enthalpy change. Enthalpy Value \Delta(()) -1300\cdot \Delta((),( graphite )) +717\cdot \Delta () +31\cdot \Delta () 0

A battery does 35 kJ of work driving an electric motor and 7 kJ of heat are released .What is the change in internal energy of the system?

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Exam 4: Thermodynamics

Calculate the standard enthalpy of combustion of butane, C4H10(g), at 298 K from standard enthalpy of formation data.

For most reactions,the value of Δ\DeltaΔ U is very close to that for Δ\DeltaΔ H

The entropy of fusion of water is +22.0 J.K-1.mol-1 > and the enthalpy of fusion of water is +6.01 J.K-1.mol-1 at 0 ο\omicronο C.At 0 ο\omicronο C, Δ\DeltaΔ Stotal for the melting of ice is

Calculate the entropy of vaporization of water at 25 ο\omicronο C and 1 bar. The molar heat capacities of the liquid and gas are 75 and 34 J·K-1·mol-1, respectively.The molar enthalpy of vaporization of water at its normal boiling point is 40.7 kJ·mol-1.

When calculating the entropy change as a result of transferring heat reversibly to or from a system,the temperature must be constant.

Calculate the standard reaction enthalpy for the following reaction: 2()\rightarrow2()+() From the standard reaction enthalpies of ()+\rightarrow2() \Delta=+180.5\cdot 2()\rightarrow()+2() \Delta=-66.4\cdot

Consider the compounds PCl5(g),HCN(g),CuO(s),NO(g),NH3(g),And SO2(g). Which compound will have approximately the same stability with respect to its elements if the temperature is raised?

The molar heat capacity of Cu(s) at 1 atm pressure has been measured over a range of temperatures from close to 0 K to 400 K. Describe how you would obtain the standard molar entropy of Cu(s) at 298 K.

The reaction CH3CH2CH2CH3(g) →\rightarrow→ CH3CH(CH3)2(g),is exothermic.This reaction will be spontaneous at high temperatures.

Predict the sign (+,-,0) of the entropy change when a glass of water reversibly loses 200 J of energy at 25°C.

In the combustion of coal,C(s),the C=O bonds are stronger than the O=O bond.

Draw a graph of the molar Gibbs free energy versus temperature for H2O(l) and H2O(g). (a)Explain the slopes of the 2 lines. (b)At low temperatures,which phase is most stable? (c)At high temperatures,which phase is more stable?

Calculate the standard entropy of fusion of ethanol at its melting point, 159 K. The standard molar enthalpy of fusion of ethanol at its melting point is 5.02 kJ.mol-1.

In a system composed of nitrogen gas in a cylinder fitted with a piston, when 2.00 kJ of energy is transferred as heat at an external pressure of 2.00 atm, The nitrogen gas expands from 2.00 to 5.00 L against this constant pressure.What is Δ\DeltaΔ U for the process?

For the reaction CO2(aq) →\rightarrow→ CO2(g), Δ\DeltaΔ Hr = 19.4 kJ.mol-1 at 298.At constant temperature and pressure,Which of the following statements is true?

The cooling of a hot metal is accompanied by an increase in entropy.

For He(g,10 atm) →\rightarrow→ He(g,1 atm),is the entropy change positive or negative?

The reaction 2Cu(s)+ CO2(g) →\rightarrow→ 2CuO(s)+ C(s) Is endothermic.Which of the following statements is true?

Match the values with the correct enthalpy change. Enthalpy Value \Delta(()) -1300\cdot \Delta((),( graphite )) +717\cdot \Delta () +31\cdot \Delta () 0

A battery does 35 kJ of work driving an electric motor and 7 kJ of heat are released .What is the change in internal energy of the system?

Atoms

Molecules

States of Matter

Equilibrium

Reactions

Kinetics

The Main-Group Elements

The D-Block Elements

Nuclear Chemistry

Organic Chemistry

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Calculate the standard enthalpy of combustion of butane, C₄H₁₀(g), at 298 K from standard enthalpy of formation data.

For most reactions,the value of $\Delta$ U is very close to that for $\Delta$ H

The entropy of fusion of water is +22.0 J.K^-¹.mol^-¹> and the enthalpy of fusion of water is +6.01 J.K^-¹.mol^-¹at 0^$\omicron$C.At 0^$\omicron$C, $\Delta$ S_total for the melting of ice is

Calculate the entropy of vaporization of water at 25^$\omicron$C and 1 bar. The molar heat capacities of the liquid and gas are 75 and 34 J·K^-¹·mol^-¹, respectively.The molar enthalpy of vaporization of water at its normal boiling point is 40.7 kJ·mol^-¹.

Consider the compounds PCl₅(g),HCN(g),CuO(s),NO(g),NH₃(g),And SO₂(g). Which compound will have approximately the same stability with respect to its elements if the temperature is raised?

The reaction CH₃CH₂CH₂CH₃(g) $\rightarrow$ CH₃CH(CH₃)₂(g),is exothermic.This reaction will be spontaneous at high temperatures.

Draw a graph of the molar Gibbs free energy versus temperature for H₂O(l) and H₂O(g). (a)Explain the slopes of the 2 lines. (b)At low temperatures,which phase is most stable? (c)At high temperatures,which phase is more stable?

Calculate the standard entropy of fusion of ethanol at its melting point, 159 K. The standard molar enthalpy of fusion of ethanol at its melting point is 5.02 kJ.mol^-¹.

In a system composed of nitrogen gas in a cylinder fitted with a piston, when 2.00 kJ of energy is transferred as heat at an external pressure of 2.00 atm, The nitrogen gas expands from 2.00 to 5.00 L against this constant pressure.What is $\Delta$ U for the process?

For the reaction CO₂(aq) $\rightarrow$ CO₂(g), $\Delta$ H_r = 19.4 kJ.mol^-¹ at 298.At constant temperature and pressure,Which of the following statements is true?

For He(g,10 atm) $\rightarrow$ He(g,1 atm),is the entropy change positive or negative?

The reaction 2Cu(s)+ CO₂(g) $\rightarrow$ 2CuO(s)+ C(s) Is endothermic.Which of the following statements is true?