Question 1

Which of the following statements is true for an ideal gas?

Accepted Answer

This statement is known as the Clausius-Clapeyron equation and is a common equation used to relate the vapor pressure of a substance to its enthalpy of vaporization. The slope of the graph is equal to -ΔHvap/R, where ΔHvap is the enthalpy of vaporization and R is the gas constant. Therefore, choice C is the correct answer.

Question 2

Use the phase digram to answer the following questions: 
-According to the phase diagram ,which point corresponds to conditions where solid,liquid,and gas phases all exist?

Accepted Answer

Point C corresponds to the triple point where solid, liquid, and gas phases all exist in equilibrium.

Question 3

If a pure substance begins at point A on the phase diagram below and the pressure on the substance is reduced at constant temperature until point B is reached,what process occurs?

Accepted Answer

D

Question 4

Mount Everest rises to a height of 29,035 ft (8.850 × 10³ m)above sea level.At this height,the atmospheric pressure is 230 mm Hg.At what temperature does water boil at the summit of Mount Everest? (ΔH_vap for H₂O = 40.7 kJ/mole,R = 8.31 J/K.mol)

Accepted Answer

The answer of Mount Everest rises to a height of...

Question 5

Carbon tetrachloride,an organic solvent,has a molar heat of vaporization of 29.82 kJ/mol.If CCl₄ has a normal boiling point of 3.50 × 10² K,what is its vapor pressure at 273 K? (R = 8.31 J/mol⋅K)

Accepted Answer

We can use the Clausius-Clapeyron equation to solve this problem:

ln(P2/P1) = -(ΔHvap/R) * (1/T2 - 1/T1)

where P1 and T1 are the known vapor pressure and temperature (3.50 × 10^2 K), respectively, P2 is the vapor pressure at the unknown temperature, T2 (273 K), ΔHvap is the molar heat of vaporization (29.82 kJ/mol), and R is the gas constant (8.31 J/mol*K).

Substituting the values and solving for P2, we get:

ln(P2/760 Torr) = -(29.82 kJ/mol / 8.31 J/mol*K) * (1/273 K - 1/350.0 K)

ln(P2/760 Torr) = -15.85

P2/760 Torr = e^(-15.85)

P2 = 42.2 Torr or mm Hg

Therefore, the vapor pressure of CCl4 at 273 K is 42.2 mm Hg, which corresponds to choice B.

Question 6

Xenon has a molar heat of vaporization of 12.6 kJ/mol and a vapor pressure of 1.00 atm at -108.0°C.What is the vapor pressure of xenon at -148.0°C? (R = 8.31 J/K.mol)

Accepted Answer

To find the vapor pressure of xenon at a new temperature, we can use the Clausius-Clapeyron equation in its integrated form:$$ \ln\left(\frac{P_2}{P_1}\right) = -\frac{\Delta H_{vap}}{R} \left(\frac{1}{T_2} - \frac{1}{T_1}\right) $$Given:- $\Delta H_{vap} = 12.6 \, \text{kJ/mol} = 12600 \, \text{J/mol}$ (conversion from kJ to J)- $R = 8.31 \, \text{J/K}\cdot\text{mol}$- $P_1 = 1.00 \, \text{atm}$- $T_1 = -108.0°C = 165K$ (conversion from °C to K: $T(K) = T(°C) + 273$)- $T_2 = -148.0°C = 125K$Rearranging the equation to solve for $P_2$:$$ \ln(P_2) = -\frac{12600}{8.31} \left(\frac{1}{125} - \frac{1}{165}\right) + \ln(1.00) $$Solving this equation gives the natural logarithm of $P_2$. To find $P_2$, we take the exponential of both sides.After calculating, you will find that $P_2$ is approximately 0.053 atm, which corresponds to choice A.

Question 7

All of the following statements are incorrect EXCEPT

Accepted Answer

The liquid phase of a pure substance cannot exist above its critical temperature because at temperatures above the critical temperature, the gas phase cannot be condensed into a liquid by increasing the pressure, making statement C correct.

Question 8

Methyl alcohol,CH₃OH,has a vapor pressure of 203 mm Hg at 35°C.If 5.00 g CH₃OH is sealed in a 10.0 L flask,what mass will remain in the liquid phase when equilibrium is established at 35°C? Assume any liquid remaining in the flask has a negligible volume.(760 mm Hg = 1 atm,R = 0.0821 L⋅atm/mol⋅K)

Accepted Answer

The answer of Methyl alcohol,CH₃OH,has a vapor pressure of 203...

Question 9

What process occurs when a substance is at point C on the phase diagram below,and the pressure is decreased (under constant temperature)until the substance is at point E?

Accepted Answer

The answer of What process occurs when a substance is...

Question 10

Freon-113,C₂Cl₃F₃,has an enthalpy of vaporization of 27.04 kJ/mol and a normal boiling point of 48°C.At what temperature is the vapor pressure of Freon-113 equal to 76.0 mm Hg? (R = 8.31 J/K.mol)

Accepted Answer

To find the temperature at which the vapor pressure of Freon-113 equals 76.0 mm Hg, we can use the Clausius-Clapeyron equation: $$ln(\frac{P_2}{P_1}) = \frac{\Delta H_{vap}}{R}(\frac{1}{T_1} - \frac{1}{T_2})$$Given:- $\Delta H_{vap} = 27.04 \, kJ/mol = 27040 \, J/mol$- $T_1 = 48°C = 321K$ (normal boiling point, where $P_1 = 1 \, atm = 760 \, mmHg$)- $P_2 = 76.0 \, mmHg = 0.1 \, atm$- $R = 8.31 \, J/K.mol$Rearranging for $T_2$ and substituting the given values, we solve for the temperature at which the vapor pressure equals 76.0 mm Hg. The calculation involves converting temperatures to Kelvin and pressures to a consistent unit (atmospheres, in this case). The correct answer is found to be in the range that corresponds to choice C, −11.4°C, after converting the final temperature back to Celsius if necessary.

Question 11

The normal boiling point of a liquid is

Accepted Answer

The normal boiling point of a liquid is the temperature at which the vapor pressure of the liquid is equal to 1 atm (atmosphere), which is called the standard pressure. This point is independent of the volume and surface area of the liquid.

Question 12

Sulfur dioxide has a vapor pressure of 462.7 mm Hg at -21.0°C and a vapor pressure of 140.5 mm Hg at -44.0°C.What is the molar heat of vaporization of sulfur dioxide? (R = 8.31 J/K⋅mol)

Accepted Answer

We can use the Clausius-Clapeyron equation to solve for the molar heat of vaporization. 
ln(P2/P1) = ΔHvap/R * (1/T1 - 1/T2)
where P1, T1 and P2, T2 are the vapor pressures and temperatures given in the problem, respectively.
Plugging in the values gives:
ln(140.5/462.7) = ΔHvap/8.31 * (1/252 - 1/229)

Solving for ΔHvap gives:
ΔHvap = -R * ln(140.5/462.7) / (1/252 - 1/229)
ΔHvap = 24.9 kJ/mol

Therefore, the answer is D) 24.9 kJ/mol.

Question 13

Which of the following equations is a correct form of the Clausius-Clapeyron equation?

Accepted Answer

The Clausius-Clapeyron equation is expressed as $\ln \frac{P_{2}}{P_{1}}=-\frac{\Delta H_{\mathrm{vap}}}{R}\left[\frac{1}{T_{2}}-\frac{1}{T_{1}}\right]$, where $\Delta H_{\mathrm{vap}}$ is the enthalpy of vaporization, R is the gas constant, and T₂ and T₁ are the temperatures at which the vapor pressures P₂ and P₁ are measured, respectively. Option B correctly represents this equation.

Question 14

Sulfur dioxide has an enthalpy of vaporization of 24.9 kJ/mol.At 205 K,SO₂ has a vapor pressure of 30.3 mm Hg.What is the normal boiling point temperature of SO₂? (R = 8.31 J/K.mol)

Accepted Answer

The normal boiling point is when the vapor pressure equals 760 mm Hg. Using the Clausius-Clapeyron equation, we can estimate the boiling point. Given the enthalpy of vaporization and the vapor pressure at 205 K, the calculation shows that the normal boiling point is approximately 263 K.

Question 15

Ethanol has a molar heat of vaporization of 42.3 kJ/mol.The compound has a vapor pressure of 1.00 atm at 78.3°C.At what temperature is the vapor pressure equal to 0.800 atm? (R = 8.31 J/K⋅mol)

Accepted Answer

We can use the Clausius-Clapeyron equation to solve this problem:

ln(P2/P1) = -(ΔHvap/R)(1/T2 - 1/T1)

Where P1 and T1 are the initial pressure and temperature, P2 is the new pressure (0.800 atm), ΔHvap is the molar heat of vaporization, R is the gas constant, and T2 is the new temperature we want to find.

Rearranging the equation and plugging in the values:

ln(0.800/1.00) = -(42.3 kJ/mol/R)(1/T2 - 1/351.45 K)
-0.2231 = -(0.00510 kJ/K/mol)(1/T2 - 0.00284 K)
1/T2 = 0.00284 K - (-0.2231 kJ/K/mol)/(0.00510 kJ/K/mol)
1/T2 = 53.5 K
T2 = 18.7°C + 273.15 = 291.85 K

Therefore, the vapor pressure of ethanol will be 0.800 atm at a temperature of 73.0°C (rounded to one decimal place). The correct answer is D.

Question 16

At 75.0 °C,water has an equilibrium vapor pressure of 289.1 mm Hg.If 4.22 g H₂O is sealed in an evacuated 5.00 L flask and heated to 75.0 °C,what mass of H₂O will be found in the gas phase when liquid-vapor equilibrium is established? Assume any liquid remaining in the flask has a negligible volume.(760 mm Hg = 1 atm,R = 0.0821 L.atm/mol.K)

Accepted Answer

The answer of At 75.0 °C,water has an equilibrium vapor...

Question 17

Naphthalene,a substance present in some mothballs,has a molar heat of vaporization of 49.4 kJ/mol.If the vapor pressure of naphthalene is 0.300 mm Hg at 298 K,what is the temperature at which the vapor pressure is 7.60 × 10² mm Hg? (R = 8.31 J/K.mol)

Accepted Answer

Using the Clausius-Clapeyron equation, the temperature at which the vapor pressure is 760 mm Hg is calculated to be approximately 491 K.

Question 18

Use the phase digram to answer the following questions: 
-According to the phase diagram ,which point corresponds to conditions where both liquid and gas phases exist?

Accepted Answer

The answer of Use the phase digram to answer the...

Question 19

Water has an equilibrium vapor pressure of 23.8 mm Hg at 25°C.What mass of water vapor is present,at equilibrium,in a room with dimensions of 7.0 m × 8.0 m × 2.7 m? (760 mm Hg = 1 atm,R = 0.0821 L.atm/mol.K)

Accepted Answer

The answer of Water has an equilibrium vapor pressure of...

Question 20

Use the phase digram to answer the following questions: 
-According to the phase diagram ,which point corresponds to conditions where only the solid phase exists?

Accepted Answer

Point A corresponds to conditions where only the solid phase exists. The temperature is below the melting point (Tm) and the vapor pressure is lower than the solid's vapor pressure.

Quiz 9: Liquids and Solids

Which of the following statements is true for an ideal gas?

Use the phase digram to answer the following questions: -According to the phase diagram ,which point corresponds to conditions where solid,liquid,and gas phases all exist?

If a pure substance begins at point A on the phase diagram below and the pressure on the substance is reduced at constant temperature until point B is reached,what process occurs?

Mount Everest rises to a height of 29,035 ft (8.850 × 10³ m) above sea level.At this height,the atmospheric pressure is 230 mm Hg.At what temperature does water boil at the summit of Mount Everest? (ΔH_vap for H₂O = 40.7 kJ/mole,R = 8.31 J/K.mol)

Carbon tetrachloride,an organic solvent,has a molar heat of vaporization of 29.82 kJ/mol.If CCl₄ has a normal boiling point of 3.50 × 10² K,what is its vapor pressure at 273 K? (R = 8.31 J/mol⋅K)

Xenon has a molar heat of vaporization of 12.6 kJ/mol and a vapor pressure of 1.00 atm at -108.0°C.What is the vapor pressure of xenon at -148.0°C? (R = 8.31 J/K.mol)

All of the following statements are incorrect EXCEPT

What process occurs when a substance is at point C on the phase diagram below,and the pressure is decreased (under constant temperature) until the substance is at point E?

Freon-113,C₂Cl₃F₃,has an enthalpy of vaporization of 27.04 kJ/mol and a normal boiling point of 48°C.At what temperature is the vapor pressure of Freon-113 equal to 76.0 mm Hg? (R = 8.31 J/K.mol)

The normal boiling point of a liquid is

Sulfur dioxide has a vapor pressure of 462.7 mm Hg at -21.0°C and a vapor pressure of 140.5 mm Hg at -44.0°C.What is the molar heat of vaporization of sulfur dioxide? (R = 8.31 J/K⋅mol)

Which of the following equations is a correct form of the Clausius-Clapeyron equation?

Sulfur dioxide has an enthalpy of vaporization of 24.9 kJ/mol.At 205 K,SO₂ has a vapor pressure of 30.3 mm Hg.What is the normal boiling point temperature of SO₂? (R = 8.31 J/K.mol)

Ethanol has a molar heat of vaporization of 42.3 kJ/mol.The compound has a vapor pressure of 1.00 atm at 78.3°C.At what temperature is the vapor pressure equal to 0.800 atm? (R = 8.31 J/K⋅mol)

Naphthalene,a substance present in some mothballs,has a molar heat of vaporization of 49.4 kJ/mol.If the vapor pressure of naphthalene is 0.300 mm Hg at 298 K,what is the temperature at which the vapor pressure is 7.60 × 10² mm Hg? (R = 8.31 J/K.mol)

Use the phase digram to answer the following questions: -According to the phase diagram ,which point corresponds to conditions where both liquid and gas phases exist?

Water has an equilibrium vapor pressure of 23.8 mm Hg at 25°C.What mass of water vapor is present,at equilibrium,in a room with dimensions of 7.0 m × 8.0 m × 2.7 m? (760 mm Hg = 1 atm,R = 0.0821 L.atm/mol.K)

Use the phase digram to answer the following questions: -According to the phase diagram ,which point corresponds to conditions where only the solid phase exists?

Quiz 9: Liquids and Solids

Which of the following statements is true for an ideal gas?

Use the phase digram to answer the following questions: -According to the phase diagram ,which point corresponds to conditions where solid,liquid,and gas phases all exist?

If a pure substance begins at point A on the phase diagram below and the pressure on the substance is reduced at constant temperature until point B is reached,what process occurs?

Mount Everest rises to a height of 29,035 ft (8.850 × 103 m) above sea level.At this height,the atmospheric pressure is 230 mm Hg.At what temperature does water boil at the summit of Mount Everest? (ΔHvap for H2O = 40.7 kJ/mole,R = 8.31 J/K.mol)

Carbon tetrachloride,an organic solvent,has a molar heat of vaporization of 29.82 kJ/mol.If CCl4 has a normal boiling point of 3.50 × 102 K,what is its vapor pressure at 273 K? (R = 8.31 J/mol⋅K)

Xenon has a molar heat of vaporization of 12.6 kJ/mol and a vapor pressure of 1.00 atm at -108.0°C.What is the vapor pressure of xenon at -148.0°C? (R = 8.31 J/K.mol)

All of the following statements are incorrect EXCEPT

What process occurs when a substance is at point C on the phase diagram below,and the pressure is decreased (under constant temperature) until the substance is at point E?

Freon-113,C2Cl3F3,has an enthalpy of vaporization of 27.04 kJ/mol and a normal boiling point of 48°C.At what temperature is the vapor pressure of Freon-113 equal to 76.0 mm Hg? (R = 8.31 J/K.mol)

The normal boiling point of a liquid is

Sulfur dioxide has a vapor pressure of 462.7 mm Hg at -21.0°C and a vapor pressure of 140.5 mm Hg at -44.0°C.What is the molar heat of vaporization of sulfur dioxide? (R = 8.31 J/K⋅mol)

Which of the following equations is a correct form of the Clausius-Clapeyron equation?

Sulfur dioxide has an enthalpy of vaporization of 24.9 kJ/mol.At 205 K,SO2 has a vapor pressure of 30.3 mm Hg.What is the normal boiling point temperature of SO2? (R = 8.31 J/K.mol)

Ethanol has a molar heat of vaporization of 42.3 kJ/mol.The compound has a vapor pressure of 1.00 atm at 78.3°C.At what temperature is the vapor pressure equal to 0.800 atm? (R = 8.31 J/K⋅mol)

Naphthalene,a substance present in some mothballs,has a molar heat of vaporization of 49.4 kJ/mol.If the vapor pressure of naphthalene is 0.300 mm Hg at 298 K,what is the temperature at which the vapor pressure is 7.60 × 102 mm Hg? (R = 8.31 J/K.mol)

Use the phase digram to answer the following questions: -According to the phase diagram ,which point corresponds to conditions where both liquid and gas phases exist?

Water has an equilibrium vapor pressure of 23.8 mm Hg at 25°C.What mass of water vapor is present,at equilibrium,in a room with dimensions of 7.0 m × 8.0 m × 2.7 m? (760 mm Hg = 1 atm,R = 0.0821 L.atm/mol.K)

Use the phase digram to answer the following questions: -According to the phase diagram ,which point corresponds to conditions where only the solid phase exists?

Mount Everest rises to a height of 29,035 ft (8.850 × 10³ m) above sea level.At this height,the atmospheric pressure is 230 mm Hg.At what temperature does water boil at the summit of Mount Everest? (ΔH_vap for H₂O = 40.7 kJ/mole,R = 8.31 J/K.mol)

Carbon tetrachloride,an organic solvent,has a molar heat of vaporization of 29.82 kJ/mol.If CCl₄ has a normal boiling point of 3.50 × 10² K,what is its vapor pressure at 273 K? (R = 8.31 J/mol⋅K)

Freon-113,C₂Cl₃F₃,has an enthalpy of vaporization of 27.04 kJ/mol and a normal boiling point of 48°C.At what temperature is the vapor pressure of Freon-113 equal to 76.0 mm Hg? (R = 8.31 J/K.mol)

Sulfur dioxide has an enthalpy of vaporization of 24.9 kJ/mol.At 205 K,SO₂ has a vapor pressure of 30.3 mm Hg.What is the normal boiling point temperature of SO₂? (R = 8.31 J/K.mol)

Naphthalene,a substance present in some mothballs,has a molar heat of vaporization of 49.4 kJ/mol.If the vapor pressure of naphthalene is 0.300 mm Hg at 298 K,what is the temperature at which the vapor pressure is 7.60 × 10² mm Hg? (R = 8.31 J/K.mol)