Exam I Flashcards

1
Q

What can we assume from the presence of a lone pair in a molecule?

A

There will be an unequal distribution of polarity, which will make the molecule behave in an unique way.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are intramolecular forces?

A

They are forces within a molecule. Examples are ionic, and covalent.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are intermolecular forces?

A

They are forces between molecules. Examples are London forces (dispersion), dipole-dipole, and Hydrogen bonding.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where can we find dispersion forces?

A

All molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where can we find dipole-dipole forces?

A

They are found in all polar molecules, which will present higher BP and MM than molecules of similar MM that are not polar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where can we find hydrogen bonds?

A

In all polar molecules with H bonds to F, O, and N. It is basically a dipole-dipole, but generally stronger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Dipole-dipole is the strongest force.

A

False; it is hydrogen bonding. However dipole-dipole is still strong, as they are permanent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Intermolecular forces only exist between molecules with ionic bounds.

A

False. Intermolecular forces exist between all substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Intermolecular forces will ___________ properties of a substance such as _____________, ______________, _____________, and others.

A

Dictate, boiling point, freezing point, vapor pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do gases, liquids, and solids differ?

A

In the freedom of movement of their constituent parts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the direction of energy when a phase changes from solid to gas?

A

Endothermic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the direction of energy when a phase changes from gas to solid?

A

Exothermic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Intermolecular forces determine ________ energy is released or absorbed (defined by ______)

A

How much, delta H

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The stronger the IMF, the lower the temperature needed to overcome them.

A

False. The higher the temperature has to be in order to overcome them.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the main differences between a crystalline and an amorphous substance?

A

Crystalline substances are regular, ordered, and have a long-term pattern; amorphous substances are still compact but without the long term order.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Intermolecular forces are ________ in nature

A

Attractive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Every substance will experience some level of dispersion forces; they are called _____________ or temporary, because they can be ________.

A

Instantaneous; induced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

The magnitude of the dispersion forces is a result of…

A

How easily the substance can be polarized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The strenght of the IMF also depends on the surface area, therefore as branch reduces, IMF reduces as well.

A

False. As branching increases, IMF reduces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What can we assume from the presence of dipole-dipole forces?

A

That the positive end of one molecule is attracted to the negative end of the other.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Because dipole-dipole represents a shift in the electron density within a substance…

A

There will be an e rich region and an e poor region in that molecule. The more the IMF increases, the more the dipole moment increases as well.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is miscibility?

A

It is the ability that one substance has to dissolve like substances.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When do we see hydrogen bonding?

A

In polar molecules where H is connected DIRECTLY to O, F, and N. Therefore, if hydrogen is bonding to a carbon that is bondind to an oxygen, it is not hydrogen bonding.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the order of the IMF’s in order of strenght?

A

Dispersion forces - Dipole-dipole - Hydrogen bonding

25
Q

Molecules that have hydrogen bonding have generally lower boiling points

A

False. They have higher boiling points because the attraction between the molecules is high, therefore it requires more energy to separate them.

26
Q

What molecule has all three types of IMF’s?

A

Water

27
Q

When can we find ion-dipole forces?

A

These forces are present when ions interact with molecular substances

28
Q

What is surface tension?

A

It is the energy needed to increase the surface area of a liquid.

29
Q

Surface tension cannot be altered

A

False. Surface tension can be altered by adding other substances into the liquid like soap for example.

30
Q

What is viscosity?

A

It is the resistance of a liquid to a flow. Generally, the higher the IMF, the higher the viscosity. Viscosity can be affected by the molecular shape, branching, or temperature

31
Q

What is capillary rise?

A

It is the natural behavior of a liquid raising on a column; it explains the meniscus shape we see when measuring liquids in a lab.

32
Q

What are adhesive forces?

A

They lead unlike substances to stick together

33
Q

What are cohesive forces?

A

They lead like substances to stick together.

34
Q

In H20, ____________ are stronger than ___________; in Hg, ____________ are weaker than ______________.

A

Adhesive, cohesive, adhesive, cohesive

35
Q

Phases changes occur during peaks of temperature.

A

False; phase changes occur at a constant temperature. The energy during a phase change is put in the transition between the phases instead of being used to change the temperature.

36
Q

What is the heat of vaporization?

A

Amount of heat required to vaporize 1 mole of a substance. The formula reads Delta H vaporization = - Delta H condensation. Delta H vaporization is endothermic, and delta H condensation is exothermic.

37
Q

Rate of evaporation = rate of condensation (dynamic equilibrium)

A

Vapor pressure

38
Q

Which state of matter is compressible?

A

Gas

39
Q

Transition between liquid and solid can also be induced by what?

A

Changes in pressure

40
Q

Gases can be condensed by…

A

Decreasing temperature or increasing pressure

41
Q

Which halogen has the highest boiling point?

A

I2

42
Q

What alcohol also presents all three IMF’s?

A

Ethanol

43
Q

The weaker the attractive forces, the higher the vapor pressure.

A

True

44
Q

What is the relationship between external pressure and boiling point?

A

They are directly related; the lower the external pressure, the lower the boiling point.

45
Q

What is the temperature required to produce a supercritical fluid?

A

Critical temperature

46
Q

What is the pressure at the critical temperature called?

A

Critical pressure

47
Q

Vaporization is an ______________ process, therefore it is ___________, while condensation is an ______________ process, therefore, it is _____________.

A

Endothermic, positive, exothermic, negative

48
Q

Cappilary action involves adhesive and cohesive forces

A

True

49
Q

Viscosity of a liquid ___________ as the temperature increases

A

Decreases

50
Q

When adding a solute to a solution, no changes are noticed in the properties of the solution.

A

False; the interferences decreases the freezing point and increases the boiling point

51
Q

A colligative property depends on the identity of the solute

A

False. It depends on the concentration of the solute and not on its identity

52
Q

The boiling point of a siolution is __________ than the pure solvent, and its freezing point is _______________ than the pure solvent.

A

Higher, lower

53
Q

What state of matter is held together with relatively high IMF’s?

A

Solid

54
Q

In the polar substance CH2O, what IMF’s are present?

A

Dispersion, dipole-dipole

55
Q

How many hidrogen bonds can a single water molecule participate in?

A

4

56
Q

What happens if an additional solid solute is added to an unsaturated solution?

A

The solute goes into solution

57
Q

What happens if addition solid solute is added to a saturated solution?

A

The solute remains an undissolved solid

58
Q
A