question

Intermolecular Forces

answer

The attractive forces that exist among the particles that compose matter.

question

Thermal Energy

answer

The energy associated with the movement of molecules and atoms.

question

Crystalline Solids

answer

Atoms and molecules are composed in 3D. (Ordered Structure)

question

Amorphous Solids

answer

Atoms and molecules have no long-range order.

question

Dispersion Force

answer

Weakest Force: Exhibited in all molecules and atoms. Result of fluctuations in electron distribution.

question

Which halogen has the highest boiling point? Cl2 Br2 I2

answer

I2

question

Polar Molecules

answer

A partial negative charge and a complementary positive charge. Asymmetric.

question

Miscibility

answer

The ability to mix without separating into two states.

question

What kind of molecule is miscible with water?

answer

A polar molecule.

question

Which molecules have dipole forces? CO2 CH2Cl2 CH4

answer

CH2Cl2

question

Which molecules have dipole-dipole forces? Cl4 CH3Cl HCl

answer

CH3Cl HCl

question

Hydrogen Bonding

answer

When H is bonded with N, O or F.

question

Rank from highest IM force to lowest. Dipole-Dipole Dispersion Hydrogen Bonding

answer

Hydrogen Bonding -> Dipole-Dipole -> Dispersion

question

Ion-Dipole Force

answer

When an ionic compound is mixed with a polar compound. (Aqueous solutions).

question

Which substance has the highest boiling point? CH3OH CO N2

answer

CH3OH

question

How many hydrogen bonds does Thymine and Adenine have? Cytosine and Guanine? (DNA)

answer

3 2

question

Surface Tension

answer

The energy required to increase the surface area by a unit amount.

question

As IM forces decrease, surface tension..... decreases increases stays the same

answer

Decreases

question

Viscosity

answer

The resistance of a liquid to flow.

question

Substances have greater viscosity when they have ________ IM forces. Higher Lower

answer

Higher

question

Viscosity increases as molecule size _________________. Increases Decreases

answer

Increases

question

What SAE oil would a car need for the summer?

answer

A high SAE number oil.

question

Capillary Action

answer

The ability of a liquid to flow against gravity up a narrow tube.

question

What two forces result in capillary action?

answer

Adhesive forces and cohesive forces.

question

Adhesive Forces

answer

The attraction between molecules and the surface of a tube.

question

Cohesive Forces

answer

The attractions between the molecules themselves.

question

Vaporization

answer

The transition of a liquid to a gas.

question

Condensation

answer

The transition of a gas to a liquid.

question

______________ IM forces cause a higher evaporation rate. Stronger Weaker

answer

Weaker

question

Volatile Chemicals

answer

Chemicals that evaporate easily.

question

Nonvolatile Chemicals

answer

Do not evaporate easily.

question

______________ temperatures cause higher evaporation rates. High Low

answer

High

question

________________ surface areas cause higher evaporation rates. Large Small

answer

Large.

question

Is vaporization endothermic or exothermic?

answer

Endothermic

question

Is condensation endothermic or exothermic?

answer

Exothermic

question

Enthalpy of Vaporization

answer

The amount of heat required to vaporize 1 mole of liquid to a gas.

question

What is the Enthalpy of Vaporization for water?

answer

ΔHvap = 40.7 kJ/mol

question

Dynamic Equilibrium

answer

When the rate of a reverse process equals that of the forward process. ex- when condensation = evaporization

question

Vapor Pressure

answer

The pressure of a gas in dynamic equilibrium with it's liquid.

question

Boiling Point

answer

The temperature at which the liquid's vapor pressure equals the external pressure.

question

Normal Boiling Pt.

answer

The temperature of a liquid where its vapor pressure equals 1 atm.

question

Supercritical Fluid

answer

Any substance beyond its critical point.

question

Critical Temperature (Tc)

answer

The temp above which a liquid cannot exist regardless of pressure.

question

Critical Pressure (Pc)

answer

The pressure required to bring about a transition to a liquid at Tc.

question

What properties do supercritical fluids hold?

answer

Liquid and Gas

question

Sublimation

answer

Solid to a gas

question

Deposition

answer

Gas to a solid

question

What is an example of sublimation?

answer

Dry Ice

question

Fusion

answer

Melting; Solid to a liquid

question

Freezing

answer

Liquid to a solid

question

Is fusion endothermic or exothermic?

answer

Endothermic

question

Heat of Fusion

answer

The amount of heat required to melt 1 mol of a solid.

question

Is freezing endothermic or exothermic?

answer

Exothermic

question

Enthalpy of Sublimation

answer

The amount of heat required to sublime 1 mol of a solid to a gas.

question

Phase Diagram

answer

A map of the state(phase) of a substance as a function of pressure (y) and temperature (x).

question

Triple Point

answer

Where all three states exist in equilibrium.

question

Critical Point

answer

Represents the temp and pressure above which the supercritical point exists. Where a liquid and gas can no longer be distinguished.

question

Dipole-Dipole Forces

answer

Exists between all molecules that are polar.

question

Permanent Dipole

answer

When two atoms in a molecule have substantially different electronegativities.

question

Sometimes when we heat food in the microwave, the lid of the container pops off. Why does this occur?

answer

The air and water vapor inside the container are expanding.

question

A substance with a fixed volume and fixed shape.

answer

Solid

question

A substance with a fixed volume but no fixed shape.

answer

Liquid

question

A substance with no fixed volume or shape.

answer

Gas

question

What factors cause changes between the liquid and gas state? A gas can be converted into a liquid by heating. A gas can be converted into a liquid by cooling. A liquid can be converted to a gas by heating. A gas can be converted into a liquid by increasing the pressure of a gas sample. A gas can be converted into a liquid by decreasing the pressure of a gas sample. A liquid can be converted to a gas by cooling.

answer

A gas can be converted into a liquid by cooling. A liquid can be converted to a gas by heating. A gas can be converted into a liquid by increasing the pressure of a gas sample.

question

What factors cause changes between the solid and liquid state? A solid can be converted to a liquid by heating. A liquid can be converted to a solid by cooling. A liquid can be converted to a solid by heating. A solid can be converted to a liquid by cooling.

answer

A solid can be converted to a liquid by heating. A liquid can be converted to a solid by cooling.

question

What are the main properties of liquids (in contrast to gases and solids)? Liquids have a definite volume. Liquids have much higher densities in comparison to gases. Liquids have an indefinite shape and do not assume the shape of their container. Liquids are easily compressed. Liquids have an indefinite shape and assume the shape of their container. Liquids are not easily compressed. Liquids do not have a definite volume. Liquids have lower densities in comparison to gases.

answer

Liquids have a definite volume. Liquids have much higher densities in comparison to gases. Liquids have indefinite shape and assume the shape of their container. Liquids are not easily compressed.

question

Which substance has the highest boiling point? CH3OH CO N2

answer

CH3OH

question

What are the correct conditions for forming a hydrogen bond?

answer

A hydrogen atom acquires a partial positive charge when it is covalently bonded to an F atom. Hydrogen bonding occurs when a hydrogen atom is covalently bonded to an N, O, or F atom. A hydrogen bond is possible with only certain hydrogen-containing compounds.

question

The hydrides of group 5A are NH3, PH3, AsH3, and SbH3. Arrange them from highest to lowest boiling point.

answer

SbH3, NH3, AsH3, SbH3.

question

Which molecules have dipole-dipole forces? HF CH3Cl SiH4

answer

HF and CH3Cl

question

How much energy is required to vaporize 135 g of butane at its boiling point? The heat of vaporization for butane is 23.1 kJ/mol.

answer

53.7 kJ (Molar mass and multiply)

question

What volume will 135 g of butane occupy at 745 torr and 35 ∘C?

answer

59.9 L (PV=nRT)

question

What happens to the vapor pressure of a substance when its surface area is increased at constant temperature?

answer

The vapor pressure remains the same.

question

If hexane (C6H14), octane (C8H18), and octanol (C8H17OH) are heated evenly at different altitudes, rank them according to the order in which you would expect them to begin boiling. Hexane at high altitude Octane at sea level Octanol at sea level Octane at high altitude

answer

Hexane at high altitude Octane at high altitude Octane at sea level Octanol at sea level

question

Which of the following statements are correct? When a solid is converted to a liquid, heat is absorbed. The average kinetic energy of the system changes while all of a solid is converted to a liquid. When heat is applied to a solid, the molecular motion decreases as the temperature increases. Temperature remains constant while all of a solid is converted to a liquid. The temperature increases while all of a liquid is converted to a gas.

answer

When a solid is converted to a liquid, heat is absorbed. Temperature remains constant while all of a solid is converted to a liquid.

question

When a small ice cube at -10∘C is put into a cup of water at room temperature, which of the following plays a greater role in cooling the liquid water: the warming of the ice from -10∘C to 0∘C , or the melting of the ice?

answer

The melting of ice.

question

How much heat energy, in kilojoules, is required to convert 52.0 g of ice at −18.0 ∘C to water at 25.0 ∘C ?

answer

24.8 kJ Go through phase changes. Solid -> liquid calculations

question

How long would it take for 1.50 mol of water at 100.0 ∘C to be converted completely into steam if heat were added at a constant rate of 18.0 J/s ?

answer

56.3 min (Convert mol to g, multiply by deltaHvap, multiply by 18 J/s)

question

What is a phase diagram?

answer

A phase diagram is simply a map of the phase of a substance as a function of pressure (on the y-axis) and temperature (on the x-axis)

question

What is the significance of crossing a line in a phase diagram?

answer

It means that a phase transition has occurred.

question

The line connecting the triple point and the critical point on a phase diagram represents _____. the temperature and pressure combinations above which only a supercritical fluid can exist the temperature and pressure combinations at which the liquid and solid states are equally stable and at equilibrium the temperature and pressure combinations at which the liquid and gas states are equally stable and at equilibrium the temperature and pressure combinations at which the solid and gas states are equally stable and at equilibrium

answer

the temperature and pressure combinations at which the liquid and gas states are equally stable and at equilibrium

question

Which intermolecular force correlates with dipole moment?

answer

Dipole-Dipole Forces

question

Which intermolecular force correlates with polarizability?

answer

Dispersion Forces

question

Carbon disulfide has a vapor pressure of 363 torr at 25∘C and a normal boiling point of 46.3∘C. Find ΔHvap for carbon disulfide.

answer

27 kJ/mol Use Clausius-Clapeyron Equation

question

Methylamine has a vapor pressure of 344 torr at -25∘C and a boiling point of -6.4∘C . Find ΔHvap for methylamine.

answer

23 kJ/mol Use Calusius-Clapeyron Equation

question

Explain why ice floats in water.

answer

Ice is less dense than water.

question

Identify the state of matter that is the most compressible.

answer

Gas

question

Identify the compound with the highest dipole moment. CH3CHO CH3CH2CH3 CH3OCH3 (CH3)2O CH3CN

answer

CH3CN

question

Identify the compound with the lowest boiling point. (CH3)2O CH3CH2CH3 CH3CN CH3OCH3 CH3CHO

answer

CH3CH2CH3

question

In DNA, adenine and thymine have ________ hydrogen bonds between them.

answer

2

question

In DNA, cytosine and guanine hydrogen bond to each other with ________ hydrogen bonds.

answer

3

question

The forces between polar molecules are known as

answer

dipole-dipole forces

question

A molecule contains hydrogen bonding if it contains hydrogen covalently bonded to

answer

F, O, and N.

question

A paper clip floating on the top of water is an example of

answer

Surface Tension

question

For automobile engines, identify the best choice of motor oil.

answer

Low SAE for Maine in the winter and high SAE for Florida in the summer.

question

Capillary action occurs because...

answer

adhesive forces are greater than cohesive forces.

question

On a phase diagram, the sublimation curve is between

answer

a solid and a gas.

question

On a phase diagram, the fusion curve is between

answer

a solid and a liquid.

question

On a phase diagram, the vaporization curve is between

answer

a liquid and a gas.

question

Define critical point.

answer

The temperature and pressure above which a supercritical fluid exists.

question

Fresh vegetables with high water content do not freeze well. Explain.

answer

Water expands when it freezes and damages the cell wall.

question

Which one of the following has a low density? Liquid Solid Gas

answer

Gas

question

Give the change in condition to go from a liquid to a gas.

answer

Increase heat or reduce pressure.

question

Which is expected to have the largest dispersion forces? F2 C9H20 SiH4 CH4

answer

C9H20

question

Which of the following has the smallest dipole-dipole forces? CO F2 CH3CH2Cl HI

answer

F2

question

Choose the molecule or compound that exhibits dipole-dipole forces as its strongest intermolecular force. BCl3 H2 CBr4 SO2 N2

answer

SO2

question

Which of the following compounds exhibits dipole-dipole forces as its strongest attraction between molecules? HBr CO2 Kr H2 CH3NH2

answer

HBr

question

Identify the compound that does not have dipole-dipole forces as its strongest force. CH3 I HCBr3 CO2 CH2 Cl2 CH3OCH3

answer

CO2

question

Which of the following compounds exhibits hydrogen bonding? HCl CH3OH CH3Br CH3SCH3

answer

CH3OH

question

Choose the compound that exhibits hydrogen bonding as its strongest intermolecular force. CH2Cl2 C2H6 CI4 CH3OH None of the above compounds exhibit hydrogen bonding.

answer

CH3OH

question

How many compounds, of the ones listed below, have hydrogen bonding? CH3(CH2)2NH2 CH3(CH2)2NH(CH2)4CH3 (CH3CH2)2N(CH2)4CH3

answer

2. CH3(CH2)2NH2 CH3(CH2)2NH(CH2)4CH3

question

Identify the compound that does NOT have hydrogen bonding. H2O (CH3)2N(CH2)3CH3 CH3(CH2)2NH2 HF CH3(CH2)5NH2

answer

(CH3)2N(CH2)3CH3

question

What is the strongest type of intermolecular force present in CHCl3?

answer

dipole-dipole

question

In liquid methanol, CH3OH which intermolecular forces are present?

answer

Dispersion, dipole-dipole and hydrogen bonding.

question

Which halogen has the highest boiling point? Br2 I2 Cl2

answer

I2

question

Choose the substance with the highest surface tension. CH3CH2CH2OH CH3CH2CH2OH CH3CH2I CH2F2 HOCH2CH2OH

answer

HOCH2CH2OH

question

Choose the substance with the lowest surface tension. C6H6 CH3SeCH2CH3 (CH3)2SO H2Se CH3CH2CH2CH3

answer

CH3CH2CH2CH3

question

Choose the substance with the highest viscosity. C2H4Br2 (CH3CH2)2CO HOCH2CH2CH2CH2OH C8H18 CI4

answer

HOCH2CH2CH2CH2OH

question

Choose the substance with the lowest viscosity. SbBr3 AsBr5 SBr2 BeBr2 OBr2

answer

BeBr2

question

Which of the following compounds has the highest boiling point? H2S H2Se AsH3 H2O

answer

H2O

question

Choose the substance with the highest vapor pressure at a given temperature. SiS2 BH3 SbH3 RbBr CH3OCH2CH3

answer

BH3

question

Which of the following substances would you predict to have the highest ΔHvap? CH3Cl HOCH2CH2OH CH3CH2OH CH3CH2CH2CH3 HF

answer

HOCH2CH2OH

question

The normal boiling point of water is ________ at sea level.

answer

100 Celsius

question

How much energy is required to heat 36.0 g H2O from a liquid at 65°C to a gas at 115°C? The following physical data may be useful. ΔHvap = 40.7 kJ/mol Cliq = 4.18 J/g°/sup>C Cgas = 2.01 J/g°/sup>C Csol = 2.09 J/g°/sup>C Tmelting = 0°/sup>C Tboiling = 100°/sup>C

answer

87.7 kJ

question

How much energy must be removed from a 125 g sample of benzene (molar mass= 78.11 g/mol) at 425.0 K to liquify the sample and lower the temperature to 335.0 K? The following physical data may be useful. ΔHvap = 33.9 kJ/mol ΔHfus = 9.8 kJ/mol Cliq = 1.73 J/g°C Cgas = 1.06 J/g°C Csol = 1.51 J/g°C Tmelting = 279.0 K Tboiling = 353.0 K

answer

67.7 kJ

question

How much energy is required to heat 87.1 g acetone (molar mass=58.08 g/mol) from a solid at -154.0°C to a liquid at -42.0°C? The following physical data may be useful. ΔHfus = 7.27 kJ/mol Cliq = 2.16 J/g°C Cgas = 1.29 J/g°C Csol = 1.65 J/g°C Tmelting = -95.0°C

answer

29.4 kJ

CHEM 122 Chp 11. – Flashcards

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