Question 1

In the ________ liquid-crystalline phase,the molecules are arranged in sheets,with their long axes parallel and their ends aligned as well.

Accepted Answer

In smectic A liquid-crystalline phase, the molecules are arranged in sheets, with their long axes parallel and their ends aligned as well. Smectic B, C, D, and E phases have distinct molecular arrangements that differ from smectic A.

Question 2

A supercritical fluid can expand like a ________ to fill a container and has a density similar to that of a ________ so can behave as a solvent.

Accepted Answer

A supercritical fluid can expand to fill a container like a gas, but it has a density similar to that of a liquid, which allows it to act as a solvent.

Question 3

Some things take longer to cook at high altitudes than at low altitudes because ________.

Accepted Answer

At high altitudes, the atmospheric pressure is lower, which leads to lower boiling points for water. Therefore, things take longer to cook as they may not reach the required temperature for cooking or boiling.

Question 4

On a phase diagram,the melting point is the same as ________.

Accepted Answer

The melting point is the temperature at which a solid substance changes to a liquid state. This occurs at the same temperature as the freezing point, which is the temperature at which a liquid changes to a solid state. On a phase diagram, the freezing/melting point is indicated by the line separating the solid and liquid phases.

Question 5

When the phase diagram for a substance has a solid-liquid phase boundary line that has a ________ slope,the substance can go from solid to liquid,within a small temperature range,via the application of pressure.

Accepted Answer

A negative slope on the solid-liquid phase boundary line indicates that increasing pressure can lower the melting point of the solid, allowing it to melt within a smaller temperature range. This is known as the pressure-melting point effect, and is seen in substances such as ice.

Question 6

On a phase diagram,the critical temperature is ________.

Accepted Answer

The critical temperature is the temperature above which a gas cannot be liquefied, regardless of the pressure applied. It is the maximum temperature at which the liquid state can exist. Above this temperature, the gas is said to be in a supercritical state, which cannot be classified as a liquid or a gas.

Question 7

Of the following,________ is an exothermic process.

Accepted Answer

Freezing is an exothermic process as it releases heat to the surroundings when a substance changes from a liquid to a solid state. Melting, subliming, and boiling are endothermic processes that require heat input to occur.

Question 8

Volatility and vapor pressure are ________.

Accepted Answer

Volatility and vapor pressure are directly proportional to one another. As the temperature increases, the vapor pressure of a substance also increases. This leads to an increase in the volatility of the substance, meaning that it evaporates more easily. Conversely, as the temperature decreases, the vapor pressure and volatility decreases as well.

Question 9

The substance with the largest heat of vaporization is ________.

Accepted Answer

The heat of vaporization is defined as the amount of heat required to convert one mole of a substance from a liquid to a gas at constant temperature and pressure. This value depends on the strength of the intermolecular forces between the particles in the liquid state. Iodine (I2) has the largest heat of vaporization among the options given, indicating that it has the strongest intermolecular forces and is therefore the most difficult to vaporize.

Question 10

The vapor pressure of a liquid ________.

Accepted Answer

The vapor pressure of a liquid increases nonlinearly with increasing temperature, typically following a curve described by the Clausius-Clapeyron relation, which shows an exponential relationship rather than a linear one.

Question 11

Which of the following is most likely to exhibit liquid-crystalline behavior?

Accepted Answer

The answer of Which of the following is most likely...

Question 12

In general,the vapor pressure of a substance increases as ________ increases.

Accepted Answer

The vapor pressure of a substance is directly proportional to the temperature. As the temperature increases, the kinetic energy of the molecules increases and more molecules are able to break free from the surface, causing an increase in vapor pressure. The other factors listed, such as surface tension, molecular weight, hydrogen bonding, and viscosity, do not have a significant impact on vapor pressure.

Question 13

A volatile liquid is one that ________.

Accepted Answer

A volatile liquid is one that readily evaporates, meaning it has a high vapor pressure at a given temperature. The other choices (A-D) describe different properties of liquids that are not necessarily related to volatility.

Question 14

On a phase diagram,the critical pressure is ________.

Accepted Answer

The critical pressure on a phase diagram is the pressure required to liquefy a gas at its critical temperature. At this point, the gas and liquid states become indistinguishable, known as the critical point. Above this pressure, it is impossible to liquefy the gas regardless of the temperature, and it will remain in the gas state.

Question 15

All of the following are characteristics of liquid crystal behavior except ________.

Accepted Answer

Liquid crystals typically do not have an ionic configuration; they are more associated with molecular structures that have long axial structures, carbon-carbon single bonds, double bonds, and polar groups.

Question 16

The critical temperature and pressure of CS₂ are 279 °C and 78 atm,respectively.A supercritical fluid can only exist at a temperature ________ 279 °C and pressure ________ 78 atm.

Accepted Answer

A supercritical fluid exists at conditions above both its critical temperature and critical pressure, so the correct answer is "above, above."

Question 17

The predominant intramolecular force in CaBr₂ is ________.

Accepted Answer

CaBr₂ contains a metal cation (Ca2+) and a nonmetal anion (Br-, S). The predominant intramolecular force in this compound is the ionic bond between the cation and anion, which is a result of the electrostatic attraction between oppositely charged ions. London-dispersion forces, dipole-dipole forces, and hydrogen bonding are intermolecular forces, which are present between molecules, while ion-dipole forces require a polar molecule and an ion, and there is no evidence of a polar molecule in the given compound.

Question 18

Of the following,________ should have the highest critical temperature.

Accepted Answer

CBr₄ should have the highest critical temperature because it has the largest molecular weight and strongest London dispersion forces among the given options, which increases the critical temperature.

Question 19

The vapor pressure of any substance at its normal boiling point is ________.

Accepted Answer

The definition of normal boiling point is the temperature at which the vapor pressure of a liquid is equal to 1 atm. Therefore, the vapor pressure of any substance at its normal boiling point is 1 atm.

Question 20

-  is the slope of a plot of the natural log of the vapor pressure of a substance versus ________.

Accepted Answer

The slope of the natural log of the vapor pressure of a substance versus 1/T (where T is the temperature in Kelvin) is equal to -ΔHvap/R, where ΔHvap is the enthalpy of vaporization and R is the gas constant. Therefore, the slope is proportional to 1/T, making choice C the best option.

Quiz 11: Liquids and Intermolecular Forces

In the ________ liquid-crystalline phase,the molecules are arranged in sheets,with their long axes parallel and their ends aligned as well.

A supercritical fluid can expand like a to fill a container and has a density similar to that of a so can behave as a solvent.

Some things take longer to cook at high altitudes than at low altitudes because ________.

On a phase diagram,the melting point is the same as ________.

When the phase diagram for a substance has a solid-liquid phase boundary line that has a ________ slope,the substance can go from solid to liquid,within a small temperature range,via the application of pressure.

On a phase diagram,the critical temperature is ________.

Of the following,________ is an exothermic process.

Volatility and vapor pressure are ________.

The substance with the largest heat of vaporization is ________.

The vapor pressure of a liquid ________.

Which of the following is most likely to exhibit liquid-crystalline behavior?

In general,the vapor pressure of a substance increases as ________ increases.

A volatile liquid is one that ________.

On a phase diagram,the critical pressure is ________.

All of the following are characteristics of liquid crystal behavior except ________.

The critical temperature and pressure of CS₂ are 279 °C and 78 atm,respectively.A supercritical fluid can only exist at a temperature 279 °C and pressure 78 atm.

The predominant intramolecular force in CaBr₂ is ________.

Of the following,________ should have the highest critical temperature.

The vapor pressure of any substance at its normal boiling point is ________.

- is the slope of a plot of the natural log of the vapor pressure of a substance versus ________.

Quiz 11: Liquids and Intermolecular Forces

In the ________ liquid-crystalline phase,the molecules are arranged in sheets,with their long axes parallel and their ends aligned as well.

A supercritical fluid can expand like a ________ to fill a container and has a density similar to that of a ________ so can behave as a solvent.

Some things take longer to cook at high altitudes than at low altitudes because ________.

On a phase diagram,the melting point is the same as ________.

When the phase diagram for a substance has a solid-liquid phase boundary line that has a ________ slope,the substance can go from solid to liquid,within a small temperature range,via the application of pressure.

On a phase diagram,the critical temperature is ________.

Of the following,________ is an exothermic process.

Volatility and vapor pressure are ________.

The substance with the largest heat of vaporization is ________.

The vapor pressure of a liquid ________.

Which of the following is most likely to exhibit liquid-crystalline behavior?

In general,the vapor pressure of a substance increases as ________ increases.

A volatile liquid is one that ________.

On a phase diagram,the critical pressure is ________.

All of the following are characteristics of liquid crystal behavior except ________.

The critical temperature and pressure of CS2 are 279 °C and 78 atm,respectively.A supercritical fluid can only exist at a temperature ________ 279 °C and pressure ________ 78 atm.

The predominant intramolecular force in CaBr2 is ________.

Of the following,________ should have the highest critical temperature.

The vapor pressure of any substance at its normal boiling point is ________.

- is the slope of a plot of the natural log of the vapor pressure of a substance versus ________.

A supercritical fluid can expand like a to fill a container and has a density similar to that of a so can behave as a solvent.

The critical temperature and pressure of CS₂ are 279 °C and 78 atm,respectively.A supercritical fluid can only exist at a temperature 279 °C and pressure 78 atm.

The predominant intramolecular force in CaBr₂ is ________.