Chapter 11: Fluids and Intermolecular Forces Flashcards Preview

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Flashcards in Chapter 11: Fluids and Intermolecular Forces Deck (28)
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1
Q

what do INTRA molecular attractions exist between?

A

chemical bonds (like the attraction between H+ and Cl- in HCl)

2
Q

what do INTER molecular attractions exist between?

A

molecules (like the attraction between one HCl molecule and another HCl molecule)

3
Q

which forces are weaker: INTRA molecular forces or INTER molecular forces?

A

Inter

4
Q

what type of INTER molecular force involves instantaneous dipole moments?

A

London dispersion forces

5
Q

what does the term ‘instantaneous dipole’ describe?

A

when a neutral atom is temporally develops a slight dipole such that it becomes attracted to another neutral atom that has temporally developed a slight dipole

6
Q

what does the term ‘polarizability’ describe?

A

the ease with which a neutral atom can temporarily develop a slight dipole (for use in dispersion force attraction)

7
Q

does polarizability increase or decrease as the number of an atom’s/molecule’s electrons increases?

A

polarizability INCREASES as the atom’s/molecule’s number of electrons increases

8
Q

dispersion force strength increase or decrease as the atomic/molecular size increases?

A

increases

9
Q

which molecular shape has stronger dispersion forces: long/cylindrical shapes or short/spherical shapes?

A

long cylindrical shapes

10
Q

does dipole:dipole force get stronger or weaker as polarity increases?

A

stronger; dipole:dipole force follows from permanent (if weak) dipole

11
Q

why does molecular size/shape impact the strength of dispersion forces?

A

bc dispersion forces get stronger with increased surface area

12
Q

if two molecules are about the same size/shape, how do you determine which one has the stronger intermolecular forces?

A

The more polar molecule will have the stronger intermolecular forces

(dipole:dipole force is the tie breaker here)

13
Q

if two polar molecules are different sizes, how do you determine which one has the stronger intermolecular forces?

A

the bigger molecule will have the stronger intermolecular forces

(even if both molecules have dipole or dipole:dipole forces, when they’re two different sizes, you compare them by their dispersion forces)

14
Q

does COhesion cause molecules to stick to themselves or to surfaces?

A

themselves

15
Q

does ADhesion cause molecules to stick to themselves or to surfaces?

A

surfaces

16
Q

when it comes to properties of liquids, what does ‘capillary action’ describe?

A

the ability of a fluid to ‘climb’ up a surface (like a capillary tube or a tree root) against gravity

17
Q

what does fusion (as in heat of fusion) describe?

A

melting

18
Q

what does vaporization (as in heat of vaporization) describe?

A

evaporating

transition from liquid to gas

19
Q

what does sublimation (as in heat of sublimation) describe?

A

transition from solid directly to gas

20
Q

what does condensation (as in heat of condensation) describe?

A

gas going to liquid

21
Q

what does deposition (as in heat of deposition) describe?

A

gas going to solid

22
Q

are the specific heats for ice, liquid water, and water vapor all the same?

A

No.

You get these from a table

23
Q

what does the term ‘critical temperature’ describe?

A

the highest temperature at which a liquid can exist

not the same as boiling point

24
Q

what does the term ‘critical pressure’ describe?

A

the pressure required to return a gas to liquid at critical temperature

25
Q

what does freezing (as in heat of freezing) describe?

A

transition of liquid to solid

26
Q

does critical temperature increase or decrease as intermolecular forces increase?

A

increase

27
Q

why do we care about critical pressure when it comes to critical temperature?

A

the pressure is what enables us to keep liquids from going to gas even though we’ve raised the temperature above the substances normal boiling/vaporization point

28
Q

what does the term ‘super critical fluid’ describe?

A

what you get once you’ve exceeded a liquid’s critical temperature and critical pressure

liquid and gas in sample are indistinguishable