Chapter 5, Problem 5.69P

Interpretation Introduction

(a)

Interpretation:

If the given equation is true or false should be determined.

Concept Introduction:

The ideal gas law relates the pressure, volume, number of moles and temperature of gas as follows:

$PV=nRT$.

Here, p is pressure, v is volume, n is number of moles, r is Universal gas constant and t is temperature of the gas.

The value of r is $0.082{\text{ L atm K}}^{-1}{\text{ mol}}^{-1}$.

Answer to Problem 5.69P

The given statement is true.

Explanation of Solution

The ideal gas is equal and holds for all ideal gases at any temperature, pressure and volume. An ideal gas is a situation of gas at which the molecules of gas have negligible interaction. This can help in performing the processes like solidification and condensation.

Interpretation Introduction

(b)

Interpretation:

If the given equation is true or false should be determined.

Concept Introduction:

The ideal gas law relates the pressure, volume, number of moles and temperature of gas as follows:

$PV=nRT$.

Here, p is pressure, v is volume, n is number of moles, r is Universal gas constant and t is temperature of the gas.

The value of r is $0.082{\text{ L atm K}}^{-1}{\text{ mol}}^{-1}$.

Answer to Problem 5.69P

The given statement is false.

Explanation of Solution

Intermolecular forces are the forces which are responsible for shape and structure of any substance. If the molecules are moving freely and attraction forces are weak then the substance is in gaseous state.

In liquid, the intermolecular forces are strong as compared to the gases thus; the molecules are closer as compared to that of gases. But not as close in solids thus, the liquid does not have the fixed shape.

Interpretation Introduction

(c)

Interpretation:

If the given equation is true or false should be determined.

Concept Introduction:

The ideal gas law relates the pressure, volume, number of moles and temperature of gas as follows:

$PV=nRT$.

Here, p is pressure, v is volume, n is number of moles, r is Universal gas constant and t is temperature of the gas.

The value of r is $0.082{\text{ L atm K}}^{-1}{\text{ mol}}^{-1}$.

Answer to Problem 5.69P

The given statement is false.

Explanation of Solution

The surface tension is the property of surface of liquid that separates it from gas and solid. It is the amount of energy that can increase the surface area of liquid.

Due to this property of liquid, it forms a layer like an elastic skin which is tough to penetrate.

Interpretation Introduction

(d)

Interpretation:

If the given equation is true or false should be determined.

Concept Introduction:

The ideal gas law relates the pressure, volume, number of moles and temperature of gas as follows:

$PV=nRT$.

Here, p is pressure, v is volume, n is number of moles, r is Universal gas constant and t is temperature of the gas.

The value of r is $0.082{\text{ L atm K}}^{-1}{\text{ mol}}^{-1}$.

Answer to Problem 5.69P

The given statement is true.

Explanation of Solution

Surface tension is an amount of energy that is required to increase the surface area of liquid. At liquid −gas interface, molecules of liquid available at surface experience more attraction towards the downward direction as compared to towards the gaseous state above it. Due to this, molecules of liquid create a layer just like an elastic skin which is tough to penetrate.

Interpretation Introduction

(e)

Interpretation:

If the given equation is true or false should be determined.

Concept Introduction:

The ideal gas law relates the pressure, volume, number of moles and temperature of gas as follows:

$PV=nRT$.

Here, p is pressure, v is volume, n is number of moles, r is Universal gas constant and t is temperature of the gas.

The value of r is $0.082{\text{ L atm K}}^{-1}{\text{ mol}}^{-1}$.

Answer to Problem 5.69P

The given statement is false.

Explanation of Solution

Surface tension is an amount of energy that is required to increase the surface area of liquid. Due to strong hydrogen bonds present in ${\text{H}}_{\text{2}}\text{O}$, molecules of water experience high attraction towards the center of liquid water. This can result into high amount of energy required to increase the surface area of water.

Interpretation Introduction

(f)

Interpretation:

If the given equation is true or false should be determined.

Concept Introduction:

The ideal gas law relates the pressure, volume, number of moles and temperature of gas as follows:

$PV=nRT$.

Here, p is pressure, v is volume, n is number of moles, r is Universal gas constant and t is temperature of the gas.

The value of r is $0.082{\text{ L atm K}}^{-1}{\text{ mol}}^{-1}$.

Answer to Problem 5.69P

The given statement is true.

Explanation of Solution

When the two opposite processes are occurring at equal rate like rate of vaporization and rate of liquefaction, the partial pressure of vapor is measured which is known as vapor pressure. This vapor pressure is directly proportional to temperature. Vapor pressure is directly proportional to temperature because as the temperature increases kinetic energy of molecules also increase. This can increase the conversion of liquid to gaseous form and vapor pressure increase till it reaches to atmospheric pressure.

(g)

Interpretation Introduction

Interpretation:

If the given equation is true or false should be determined.

Concept Introduction:

The temperature is directly proportional to vapor pressure and average kinetic energy of liquid molecules.

Answer to Problem 5.69P

The given statement is true.

Explanation of Solution

As there is a direct connection in between temperature and kinetic energy of molecules of liquid, the molecules with high kinetic energy gets converted into gas. The molecules with low kinetic energy remain in the liquid phase and the temperature of liquid drops as the evaporation occurs. Conversion of high kinetic energy holding molecules of liquid to gaseous leads to evaporation and decrease in the temperature of liquid.

Interpretation Introduction

(h)

Interpretation:

If the given statement is true or false should be identified.

Concept Introduction:

Evaporation is a process in which the high kinetic energy containing molecules are converted into gas.

Answer to Problem 5.69P

The given statement is true.

Explanation of Solution

The temperature is directly proportional to average kinetic energy of molecules present in the liquid sample. These molecules have more tendencies to get converted to gaseous form. Thus, the number of molecules with high kinetic energy decreases and that of low kinetic energy increases.

Thus due to evaporation, the temperature of liquid decreases.

Interpretation Introduction

(i)

Interpretation:

If the given statement is true or false should be identified.

Concept Introduction:

Boiling point is defined as a temperature at which the atmospheric pressure and vapor pressure becomes equal.

Answer to Problem 5.69P

The given statement is true.

Explanation of Solution

All liquids have a physical property of boiling point. Boiling point is defined as the temperature of liquid when the pressure of atmosphere and vapor pressure of surface of liquid becomes equal. When the atmospheric pressure is 1atm, the boiling point of liquid is called as normal boiling point of liquid.

Interpretation Introduction

(j)

Interpretation:

If the given statement is true or false should be identified.

Concept Introduction:

The boiling point of liquid is proportional to the atmospheric pressure because it is the temperature at which vapor pressure of liquid and atmospheric pressure gets equal.

Answer to Problem 5.69P

The given statement is true.

Explanation of Solution

The boiling point is known as the temperature at which equal values are measured for both vapor pressure of liquid and atmospheric pressure. As per definition of boiling point, an increase in atmospheric pressure can result into increase of boiling point of liquid. The atmospheric pressure and boiling point of liquid are directly proportional to each other.

Interpretation Introduction

(k)

Interpretation:

If the given statement is true or false should be identified.

Concept Introduction:

As per definition of boiling point, an increase in atmospheric pressure can result into increase of boiling point of liquid.

Answer to Problem 5.69P

The given statement is false.

Explanation of Solution

The temperature of liquid at which the liquid vapor pressure and the atmospheric pressure is having same value is known as boiling point of liquid. The boiling point is a temperature of liquid that does not have any connection with heat applied to liquid for increasing the temperature. The temperature of boiling water is not related to how vigorously it is boiling because the heat applied to liquid to raise the temperature does not affect its boiling point temperature.

Interpretation Introduction

(l)

Interpretation:

If the given statement is true or false should be identified.

Concept Introduction:

As per definition of boiling point, an increase in atmospheric pressure can result into increase of boiling point of liquid.

Answer to Problem 5.69P

The given statement is false.

Explanation of Solution

After studying the molecular weight, scientist had determined that the boiling point of covalent compounds depends upon the intermolecular forces, numbers of sites of intermolecular interactions (surface area) and molecular shape of liquid compound. The most important factors to determine the boiling point of liquid are intermolecular forces, the number of sites available for intermolecular interaction and shape of molecule.

Interpretation Introduction

(m)

Interpretation:

If the given statement is true or false should be identified.

Concept Introduction:

According to studies performed by scientist, factors to determine the boiling point of liquid are intermolecular forces, the number of sites available for intermolecular interaction and shape of molecule.

Answer to Problem 5.69P

The given statement is true.

Explanation of Solution

Water has molecular weight of 18 and ethanol has molecular weight of 48. Ethanol has one hydrogen available for hydrogen bonding whereas water has two hydrogen available for hydrogen bonding. The water molecule forms hydrogen bonds and results into low vapor pressure. Ethanol does not form any hydrogen bonds and have high vapor pressure as compared to water at ${25}^0\text{C}$. Thus, because of hydrogen bonding type of intermolecular force water has low vapor pressure as compared to ethanol.

Interpretation Introduction

(n)

Interpretation:

If the given statement is true or false should be identified.

Concept Introduction:

According to studies performed by scientist, factors to determine the boiling point of liquid are intermolecular forces, the number of sites available for intermolecular interaction and shape of molecule.

Answer to Problem 5.69P

The given statement is false.

Explanation of Solution

The numbers of site present for intermolecular attraction is responsible for boiling point of the liquid. The more numbers of sites with larger area is available in hexane as compared to methane. The larger area as well as more numbers of electrons present in hexane for intermolecular interaction is basic reason for its higher boiling point compared to methane.

Interpretation Introduction

(o)

Interpretation:

If the given statement is true or false should be identified.

Concept Introduction:

Hydrogen bonding occurs when the positive end of one dipole and negative end of other dipole connected due to attraction.

Answer to Problem 5.69P

The given statement is true.

Explanation of Solution

The molecules present in water are hydrogen and oxygen. The hydrogen can bind to atoms like O, N, F which have high electro negativity. Just like this oxygen is having electronegativity that can represents the negative dipole of water for formation of hydrogen bond.

Interpretation Introduction

(p)

Interpretation:

If the given statement is true or false should be identified.

Concept Introduction:

After studying the molecular weight, scientist had determined that the boiling point of covalent compounds depends upon the intermolecular forces, numbers of sites of intermolecular interactions (surface area) and molecular shape of liquid compound.

Answer to Problem 5.69P

The given statement is false.

Explanation of Solution

The nonpolar compound have London dispersion forces present as intermolecular forces of molecules. The arrangement of atoms present in molecule is responsible for its boiling point. A compound with straight chain arrangements of molecules can have larger surface area and higher boiling point as compared to compounds having branched arrangements.