Question 1

Calculate the change in molar entropy when 2.00 mol of ozone are compressed isothermally to one quarter of its original volume.Treat ozone as an ideal gas.

Accepted Answer

A

Question 2

The enthalpy of fusion of H₂O(s)at its normal melting point is 6.01 kJ.mol^-¹.The entropy change for freezing 1 mol of water at this temperature is

Accepted Answer

E

Question 3

Use Trouton's constant to estimate the enthalpy of vaporization of diethyl ether,which boils at 309 K.

Accepted Answer

Trouton's constant is given as 85 J/molK. 
The enthalpy of vaporization (ΔHvap) is related to the boiling point (Tb) and molar entropy of vaporization (ΔSvap) by the Clausius-Clapeyron equation:

ΔHvap = TbΔSvap

Using Trouton's constant, we can estimate the molar entropy of vaporization as:

ΔSvap = R ln(P2/P1)

where R is the gas constant, P2 is the vapor pressure at the boiling point, and P1 is the vapor pressure at a lower temperature (usually the normal boiling point). Assuming ideal gas behavior, we can use the Antoine equation to estimate the vapor pressure at different temperatures:

log (P / Pa) = A - B / (T/K)

For diethyl ether, the Antoine coefficients are:

A = 4.72515 
B = 1668.21
C = -35.48

Using these values, we can estimate the vapor pressure at the normal boiling point (34.5 kPa) and at 309 K (101.9 kPa). Plugging these values into the equation above, we get:

ΔSvap = 64.8 J/Kmol

Finally, we can use this value along with Trouton's constant and the boiling point to estimate the enthalpy of vaporization:

ΔHvap = TbΔSvap = 309 K x 64.8 J/Kmol = 20 kJ/mol

The only answer choice close to this value is B) +26 kJ/mol, which is the best choice.

Question 4

What is the change in entropy when the pressure of an ideal gas is increased at constant temperature? Choose from +,0,-.

Accepted Answer

The answer of What is the change in entropy when...

Question 5

The change in molar entropy for vaporization of all liquids is about the same.True or false?

Accepted Answer

The change in molar entropy for vaporization of liquids is relatively constant, typically around 85-88 J/mol·K, because the process involves a similar increase in disorder or randomness when a liquid becomes a gas, regardless of the specific liquid.

Question 6

Calculate the change in molar entropy when the pressure of argon is allowed to double isothermally (assume ideal behavior).

Accepted Answer

The answer of Calculate the change in molar entropy when...

Question 7

Use Trouton's constant to estimate the enthalpy of condensation of diethyl ether,which boils at 309 K.

Accepted Answer

The answer of Use Trouton's constant to estimate the enthalpy...

Question 8

The molar entropy of silver at 298 K is equal to the area under the curve obtained by plotting (from T = 0 to T = 298 K)

Accepted Answer

The answer of The molar entropy of silver at 298...

Question 9

Calculate the standard entropy of vaporization of ethanol at its boiling point,352 K.The standard molar enthalpy of vaporization of ethanol at its boiling point is 40.5 kJ.mol ^- ¹.

Accepted Answer

The standard entropy of vaporization ($\Delta S_{vap}$) can be calculated using the formula $\Delta S_{vap} = \frac{\Delta H_{vap}}{T}$, where $\Delta H_{vap}$ is the enthalpy of vaporization (40.5 kJ/mol) and $T$ is the temperature in Kelvin (352 K). Converting $\Delta H_{vap}$ to J/mol (1 kJ = 1000 J), we get 40500 J/mol. Thus, $\Delta S_{vap} = \frac{40500 J/mol}{352 K} \approx 115 J/(mol \cdot K)$.

Question 10

All entropies of fusion are positive.True or false?

Accepted Answer

Entropies of fusion represent the change in entropy when a solid substance melts into a liquid. As the disorder and randomness increase when a solid becomes a liquid, the entropy of fusion is always positive. Therefore, the statement is true.

Question 11

Calculate the standard entropy of condensation of chloroform at its boiling point,335 K.The standard molar enthalpy of vaporization of chloroform at its boiling point is 31.4 kJ.mol^-¹.

Accepted Answer

The standard entropy of condensation can be calculated using the formula ΔS = ΔH/T, where ΔH is the enthalpy change and T is the temperature in Kelvin. Given that the enthalpy of vaporization is 31.4 kJ/mol (which is equivalent to 31400 J/mol for conversion to Joules) and the temperature is 335 K, the entropy of condensation (which is the negative of the entropy of vaporization) is calculated as -31400 J/mol / 335 K = -93.7 J/K·mol.

Question 12

The cooling of a hot metal is accompanied by an increase in entropy.True or false?

Accepted Answer

When a hot metal cools, the atoms or molecules move slower, and there is a decrease in order or organization. This increase in disorder and randomness results in an increase in entropy.

Question 13

Consider the following processes (treat all gases as ideal).
1.The pressure of 1 mole of oxygen gas is allowed to double isothermally.
2.Carbon dioxide is allowed to expand isothermally to 10 times its original volume.
3.The temperature of 1 mol of helium is increased 25 $\degree$C at constant pressure.
4.Nitrogen gas is compressed isothermally to half its original volume.
"5.A glass of water loses 100 J of energy reversibly at 30 $\degree$C.
Which of these processes lead(s)to an increase in entropy?"

Accepted Answer

The answer of Consider the following processes (treat all gases...

Question 14

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

The answer of The molar heat capacity of Cu(s)at 1...

Question 15

Consider the following processes (treat all gases as ideal).
1.The pressure of 1 mol of oxygen gas is allowed to double isothermally.
2.Carbon dioxide is allowed to expand isothermally to 10 times its original volume.
3.The temperature of 1 mol of helium is increased 25 $\degree$C at constant pressure.
4.Nitrogen gas is compressed isothermally to half its original volume.
"5.A glass of water loses 100 J of energy reversibly at 30 $\degree$C.
Which of these processes lead(s)to a decrease in entropy?"

Accepted Answer

Entropy decreases when a system undergoes a process that results in a decrease in the number of accessible microstates. In isothermal compression (process 4), the volume decreases, leading to a decrease in entropy. In process 5, the loss of energy from the water decreases its entropy.

Question 16

Calculate the normal boiling point of chloroform,given that the standard entropy and enthalpy of vaporization of chloroform is +93.7 J∙K ^- ¹∙mol ^- ¹ and 31.4 kJ∙mol ^- ¹.

Accepted Answer

The answer of Calculate the normal boiling point of chloroform,given...

Question 17

The temperature of 2.00 mol Ne(g)is increased from 25$\degree$C to 200$\degree$C at constant pressure.Calculate the change in the entropy of neon (assume ideal behavior).

Accepted Answer

The change in entropy can be calculated using the formula:
ΔS = nCvln(T₂/T₁)
where n is the number of moles, Cv is the molar heat capacity at constant volume, T₁ and T₂ are the initial and final temperatures in Kelvin.

For neon, Cv = (3/2)R, where R is the gas constant.
ΔS = 2(3/2)Rln(473/298) = 19.2 J/K

Therefore, the best choice is B, which matches the calculated value.

Question 18

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

The standard entropy of fusion ($\Delta S_{fus}$) can be calculated using the formula $\Delta S_{fus} = \frac{\Delta H_{fus}}{T}$, where $\Delta H_{fus}$ is the enthalpy of fusion and $T$ is the temperature in Kelvin. Given $\Delta H_{fus} = 5.02 \, \text{kJ/mol}$ and $T = 159 \, \text{K}$, converting $\Delta H_{fus}$ to J/mol gives $5020 \, \text{J/mol}$. Thus, $\Delta S_{fus} = \frac{5020 \, \text{J/mol}}{159 \, \text{K}} \approx 31.6 \, \text{J/mol}\cdot\text{K}$.

Question 19

For a given transfer of energy,a greater change in disorder occurs when the temperature is high.True or false?

Accepted Answer

A greater change in disorder, or increase in entropy, occurs when energy is transferred at a lower temperature because the same amount of energy results in a proportionally larger change in entropy at lower temperatures.

Question 20

Calculate the change in entropy of a large pail of water after 200 J of energy is reversibly transferred to the water at 20 $\degree$C.

Accepted Answer

The answer of Calculate the change in entropy of a...

Quiz 9: Thermodynamics: the Second and Third Laws

Calculate the change in molar entropy when 2.00 mol of ozone are compressed isothermally to one quarter of its original volume.Treat ozone as an ideal gas.

The enthalpy of fusion of H₂O(s) at its normal melting point is 6.01 kJ.mol^-¹.The entropy change for freezing 1 mol of water at this temperature is

Use Trouton's constant to estimate the enthalpy of vaporization of diethyl ether,which boils at 309 K.

What is the change in entropy when the pressure of an ideal gas is increased at constant temperature? Choose from +,0,-.

The change in molar entropy for vaporization of all liquids is about the same.True or false?

Calculate the change in molar entropy when the pressure of argon is allowed to double isothermally (assume ideal behavior) .

Use Trouton's constant to estimate the enthalpy of condensation of diethyl ether,which boils at 309 K.

The molar entropy of silver at 298 K is equal to the area under the curve obtained by plotting (from T = 0 to T = 298 K)

Calculate the standard entropy of vaporization of ethanol at its boiling point,352 K.The standard molar enthalpy of vaporization of ethanol at its boiling point is 40.5 kJ.mol ^- ¹.

All entropies of fusion are positive.True or false?

Calculate the standard entropy of condensation of chloroform at its boiling point,335 K.The standard molar enthalpy of vaporization of chloroform at its boiling point is 31.4 kJ.mol^-¹.

The cooling of a hot metal is accompanied by an increase in entropy.True or false?

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.

Calculate the normal boiling point of chloroform,given that the standard entropy and enthalpy of vaporization of chloroform is +93.7 J∙K ^- ¹∙mol ^- ¹ and 31.4 kJ∙mol ^- ¹.

The temperature of 2.00 mol Ne(g) is increased from 25 $\degree$ C to 200 $\degree$ C at constant pressure.Calculate the change in the entropy of neon (assume ideal behavior) .

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.

For a given transfer of energy,a greater change in disorder occurs when the temperature is high.True or false?

Calculate the change in entropy of a large pail of water after 200 J of energy is reversibly transferred to the water at 20 $\degree$ C.

Quiz 9: Thermodynamics: the Second and Third Laws

Calculate the change in molar entropy when 2.00 mol of ozone are compressed isothermally to one quarter of its original volume.Treat ozone as an ideal gas.

The enthalpy of fusion of H2O(s) at its normal melting point is 6.01 kJ.mol-1.The entropy change for freezing 1 mol of water at this temperature is

Use Trouton's constant to estimate the enthalpy of vaporization of diethyl ether,which boils at 309 K.

What is the change in entropy when the pressure of an ideal gas is increased at constant temperature? Choose from +,0,-.

The change in molar entropy for vaporization of all liquids is about the same.True or false?

Calculate the change in molar entropy when the pressure of argon is allowed to double isothermally (assume ideal behavior) .

Use Trouton's constant to estimate the enthalpy of condensation of diethyl ether,which boils at 309 K.

The molar entropy of silver at 298 K is equal to the area under the curve obtained by plotting (from T = 0 to T = 298 K)

Calculate the standard entropy of vaporization of ethanol at its boiling point,352 K.The standard molar enthalpy of vaporization of ethanol at its boiling point is 40.5 kJ.mol - 1.

All entropies of fusion are positive.True or false?

Calculate the standard entropy of condensation of chloroform at its boiling point,335 K.The standard molar enthalpy of vaporization of chloroform at its boiling point is 31.4 kJ.mol-1.

The cooling of a hot metal is accompanied by an increase in entropy.True or false?

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.

Calculate the normal boiling point of chloroform,given that the standard entropy and enthalpy of vaporization of chloroform is +93.7 J∙K - 1∙mol - 1 and 31.4 kJ∙mol - 1.

The temperature of 2.00 mol Ne(g) is increased from 25 °\degree° C to 200 °\degree° C at constant pressure.Calculate the change in the entropy of neon (assume ideal behavior) .

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.

For a given transfer of energy,a greater change in disorder occurs when the temperature is high.True or false?

Calculate the change in entropy of a large pail of water after 200 J of energy is reversibly transferred to the water at 20 °\degree° C.

The enthalpy of fusion of H₂O(s) at its normal melting point is 6.01 kJ.mol^-¹.The entropy change for freezing 1 mol of water at this temperature is

Calculate the standard entropy of vaporization of ethanol at its boiling point,352 K.The standard molar enthalpy of vaporization of ethanol at its boiling point is 40.5 kJ.mol ^- ¹.

Calculate the standard entropy of condensation of chloroform at its boiling point,335 K.The standard molar enthalpy of vaporization of chloroform at its boiling point is 31.4 kJ.mol^-¹.

Calculate the normal boiling point of chloroform,given that the standard entropy and enthalpy of vaporization of chloroform is +93.7 J∙K ^- ¹∙mol ^- ¹ and 31.4 kJ∙mol ^- ¹.

The temperature of 2.00 mol Ne(g) is increased from 25 $\degree$ C to 200 $\degree$ C at constant pressure.Calculate the change in the entropy of neon (assume ideal behavior) .

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.

Calculate the change in entropy of a large pail of water after 200 J of energy is reversibly transferred to the water at 20 $\degree$ C.