Question 1

Which explanation best describes surface tension?

Accepted Answer

Surface tension is the cohesive force exerted by molecules at the surface of a liquid. This force results in molecules experiencing a net inward force towards the liquid's interior, creating a "skin" on the surface of the liquid.

Question 2

From a consideration of the phase diagram below,a change from point M to point N corresponds to

Accepted Answer

The answer of From a consideration of the phase diagram...

Question 3

The critical point of CCl₄ is 283°C and 45 atm pressure.Liquid CCl₄ has a vapor pressure of 10.0 atm at 178°C.Which of the following statements must be true?

Accepted Answer

The triple point must be less than 178°C because at 178°C, the vapor pressure is already 10 atm, indicating that the substance is in the liquid phase at this temperature and pressure.

Question 4

The triple point of iodine is at 90 torr and 115°C.This means that liquid I₂

Accepted Answer

The answer of The triple point of iodine is at...

Question 5

Choose the correct statement about the diagram below.

Accepted Answer

The answer of Choose the correct statement about the diagram...

Question 6

In which of the following substances are intermolecular forces of attraction absent?

Accepted Answer

NaCl(l) has ionic bonds and not intermolecular forces of attraction. The other substances listed have intermolecular forces of attraction.

Question 7

If the liquid of a pure substance has a lower density than the solid,what is the effect on the pressure-temperature phase diagram?

Accepted Answer

When the liquid is less dense than the solid, the melting-point curve in the phase diagram has a positive slope, indicating that increasing pressure raises the melting point.

Question 8

If the diameter of a spherical water droplet is 100.0 μm,how much energy is required to increase the diameter of the water droplet by 5.0 μm? The surface tension of water is 1.0 × 10^-3 J/m².

Accepted Answer

The answer of If the diameter of a spherical water...

Question 9

What is the enthalpy of vaporization of a compound that has a vapor pressure of 151 mmHg at 247 K and 1.52 mmHg at 187 K? (R = 8.31 J/(K· mol))

Accepted Answer

The enthalpy of vaporization can be calculated using the Clausius-Clapeyron equation, which relates the vapor pressure of a substance at two different temperatures to its enthalpy of vaporization ($\Delta H_{vap}$). The equation in its logarithmic form is:$$\ln\left(\frac{P_2}{P_1}\right) = -\frac{\Delta H_{vap}}{R}\left(\frac{1}{T_2} - \frac{1}{T_1}\right)$$Given:- $P_1 = 1.52 \, \text{mmHg}$- $P_2 = 151 \, \text{mmHg}$- $T_1 = 187 \, \text{K}$- $T_2 = 247 \, \text{K}$- $R = 8.31 \, \text{J/(K·mol)}$First, convert pressures to the same units if necessary (in this case, both are already in mmHg, so no conversion is needed). Then, solve for $\Delta H_{vap}$:$$\ln\left(\frac{151}{1.52}\right) = -\frac{\Delta H_{vap}}{8.31}\left(\frac{1}{247} - \frac{1}{187}\right)$$Solving this equation for $\Delta H_{vap}$ gives a value in J/mol, which can then be converted to kJ/mol by dividing by 1000. The correct calculation leads to an enthalpy of vaporization close to 29 kJ/mol, indicating that option D is correct.

Question 10

Which of the following statements concerning the accompanying phase diagram is false?

Accepted Answer

The answer of Which of the following statements concerning the...

Question 11

Below is a phase diagram for a substance.  Which line represents the melting-point curve of the substance?

Accepted Answer

The answer of Below is a phase diagram for a...

Question 12

Below is a phase diagram for a substance.  What is the name for point Z on the diagram?

Accepted Answer

Point Z on the diagram is the critical point. This is where the liquid and gas phases have the same density (and thus become indistinguishable) and marks the highest temperature and pressure at which the substance can exist in a liquid phase.

Question 13

Which is the best reason for why water in a glass capillary has a concave meniscus,while mercury in a glass capillary has a convex meniscus?

Accepted Answer

The concave meniscus of water in a glass capillary is due to the strong attraction between water molecules and the glass, causing the water to climb up the sides of the container. Mercury, on the other hand, has a convex meniscus because it is less attracted to the glass than water is, leading to the mercury not climbing up the sides and instead forming a convex shape as the cohesive forces within the mercury are stronger than the adhesive forces between the mercury and the glass.

Question 14

The measure of the resistance to flow of a liquid is

Accepted Answer

Viscosity is defined as the resistance to flow of a liquid. It is caused by the friction between the particles of a liquid as they move past each other. The other options are not related to the measure of resistance to flow of a liquid.

Question 15

Knowing that ΔH_vap for water is 40.7 kJ/mol,calculate P_vap of water at 37°C.

Accepted Answer

Using the Clausius-Clapeyron equation and the known ΔHvap, the vapor pressure of water at 37°C is calculated to be approximately 52.7 torr.

Question 16

For a particular liquid,raising its temperature from 339 K to 365 K causes its vapor pressure to double.What is the enthalpy of vaporization of this liquid? (R = 8.31 J/(K · mol))

Accepted Answer

The Clausius-Clapeyron equation relates the change in vapor pressure with temperature to the enthalpy of vaporization. Using the equation ln(P2/P1) = -ΔHvap/R * (1/T2 - 1/T1), where P2/P1 = 2, T1 = 339 K, T2 = 365 K, and R = 8.31 J/(K·mol), solving for ΔHvap gives approximately 27,000 J/mol or 27 kJ/mol.

Question 17

Below is a phase diagram for a substance.  Which line represents the vapor-pressure curve of the substance?

Accepted Answer

The vapor-pressure curve represents the conditions at which the substance transitions between the liquid and gas phases, so it is the line that separates the liquid (L) and gas (G) phases in the diagram. Option B (X-Z) is the line that separates the L and G phases, so it is the vapor-pressure curve.

Question 18

Below is a phase diagram for a substance.  What is the name for point X on the diagram?

Accepted Answer

Point X on a phase diagram is known as the triple point, where all three phases (solid, liquid, and gas) coexist in equilibrium. It is the unique point where the substance can exist in all three phases at the same temperature and pressure.

Question 19

Given the accompanying phase diagram,under what conditions will solid be found in equilibrium with either liquid or gas?

Accepted Answer

Solid can exist in equilibrium with either liquid or gas along the lines where the phase boundaries of solid-liquid (curve AB) and solid-gas (curve AD) intersect. Therefore, the correct answer is D, which includes both curve AB and curve AD. Curve AC represents the boundary between liquid and gas phases and does not involve solid, so it is not relevant to this question.

Question 20

In the accompanying phase diagram,a liquid can be present at combinations of temperature and pressure corresponding to points

Accepted Answer

Points A, C, D, and F are within the liquid phase region of the phase diagram. Therefore, a liquid can be present at combinations of temperature and pressure corresponding to these points. Points G and E are within the gas phase region, and point B is within the solid phase region, so a liquid cannot be present at those points.

Quiz 11: States of Matter; Liquids and Solids

Which explanation best describes surface tension?

From a consideration of the phase diagram below,a change from point M to point N corresponds to

The critical point of CCl₄ is 283°C and 45 atm pressure.Liquid CCl₄ has a vapor pressure of 10.0 atm at 178°C.Which of the following statements must be true?

The triple point of iodine is at 90 torr and 115°C.This means that liquid I₂

Choose the correct statement about the diagram below.

In which of the following substances are intermolecular forces of attraction absent?

If the liquid of a pure substance has a lower density than the solid,what is the effect on the pressure-temperature phase diagram?

If the diameter of a spherical water droplet is 100.0 μm,how much energy is required to increase the diameter of the water droplet by 5.0 μm? The surface tension of water is 1.0 × 10^-3 J/m².

What is the enthalpy of vaporization of a compound that has a vapor pressure of 151 mmHg at 247 K and 1.52 mmHg at 187 K? (R = 8.31 J/(K· mol) )

Which of the following statements concerning the accompanying phase diagram is false?

Below is a phase diagram for a substance. Which line represents the melting-point curve of the substance?

Below is a phase diagram for a substance. What is the name for point Z on the diagram?

Which is the best reason for why water in a glass capillary has a concave meniscus,while mercury in a glass capillary has a convex meniscus?

The measure of the resistance to flow of a liquid is

Knowing that ΔH_vap for water is 40.7 kJ/mol,calculate P_vap of water at 37°C.

For a particular liquid,raising its temperature from 339 K to 365 K causes its vapor pressure to double.What is the enthalpy of vaporization of this liquid? (R = 8.31 J/(K · mol) )

Below is a phase diagram for a substance. Which line represents the vapor-pressure curve of the substance?

Below is a phase diagram for a substance. What is the name for point X on the diagram?

Given the accompanying phase diagram,under what conditions will solid be found in equilibrium with either liquid or gas?

In the accompanying phase diagram,a liquid can be present at combinations of temperature and pressure corresponding to points

Quiz 11: States of Matter; Liquids and Solids

Which explanation best describes surface tension?

From a consideration of the phase diagram below,a change from point M to point N corresponds to

The critical point of CCl4 is 283°C and 45 atm pressure.Liquid CCl4 has a vapor pressure of 10.0 atm at 178°C.Which of the following statements must be true?

The triple point of iodine is at 90 torr and 115°C.This means that liquid I2

Choose the correct statement about the diagram below.

In which of the following substances are intermolecular forces of attraction absent?

If the liquid of a pure substance has a lower density than the solid,what is the effect on the pressure-temperature phase diagram?

If the diameter of a spherical water droplet is 100.0 μm,how much energy is required to increase the diameter of the water droplet by 5.0 μm? The surface tension of water is 1.0 × 10-3 J/m2.

What is the enthalpy of vaporization of a compound that has a vapor pressure of 151 mmHg at 247 K and 1.52 mmHg at 187 K? (R = 8.31 J/(K· mol) )

Which of the following statements concerning the accompanying phase diagram is false?

Below is a phase diagram for a substance. Which line represents the melting-point curve of the substance?

Below is a phase diagram for a substance. What is the name for point Z on the diagram?

Which is the best reason for why water in a glass capillary has a concave meniscus,while mercury in a glass capillary has a convex meniscus?

The measure of the resistance to flow of a liquid is

Knowing that ΔHvap for water is 40.7 kJ/mol,calculate Pvap of water at 37°C.

For a particular liquid,raising its temperature from 339 K to 365 K causes its vapor pressure to double.What is the enthalpy of vaporization of this liquid? (R = 8.31 J/(K · mol) )

Below is a phase diagram for a substance. Which line represents the vapor-pressure curve of the substance?

Below is a phase diagram for a substance. What is the name for point X on the diagram?

Given the accompanying phase diagram,under what conditions will solid be found in equilibrium with either liquid or gas?

In the accompanying phase diagram,a liquid can be present at combinations of temperature and pressure corresponding to points

The critical point of CCl₄ is 283°C and 45 atm pressure.Liquid CCl₄ has a vapor pressure of 10.0 atm at 178°C.Which of the following statements must be true?

The triple point of iodine is at 90 torr and 115°C.This means that liquid I₂

If the diameter of a spherical water droplet is 100.0 μm,how much energy is required to increase the diameter of the water droplet by 5.0 μm? The surface tension of water is 1.0 × 10^-3 J/m².

Knowing that ΔH_vap for water is 40.7 kJ/mol,calculate P_vap of water at 37°C.