Chp. 13.1 - Types of Solutions: Intermolecular Forces and Solubility Flashcards Preview

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Flashcards in Chp. 13.1 - Types of Solutions: Intermolecular Forces and Solubility Deck (33)
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1

It dissolves in a solvent to form a solution.

Solute

2

Solvent

In general, the most abundant component

3

Soluble in each other in any proportion

Miscible

4

The maximum amount that dissolves in a fixed quantity of a given solvent @ a given temperature, where an excess of the solute is present.

Solubility

5

The rule-of-thumb "like dissolves like".

Substances with similar types of intermolecular forces dissolve in each other.

6

_______ forces are the principal force involved when an ionic compound dissolves in water.

Ion-dipole

7

As an ion separates, water molecules cluster around it in ________________.

hydration shells

8

In the innermost hydration shell, normal _____ bonding is disrupted to form the ___________ forces.

H, ion-dipole

9

______ bonding if the principal force in solutions of polar, O- and N-containing organic and biological compounds.

H

10

In the absence of H-bonding, ____________ allow polar molecules like propanal (CH3CH2CHO) to dissolve in polar solvents like dichloromethane (CH2Cl2).

dipole-dipole forces

11

A type of charge-induced dipole force that relies on polarizability. It arises when an ion's charge distorts the electron cloud of a nonpolar molecule.

Ion-induced dipole forces

12

__________ forces are based on polarizability and arise when a polar molecule distorts the electron cloud of a nonpolar molecule. They are _________ than ion-induced dipole forces because the charge of each pole is less than an ion's (Coulomb's law).

Dipole-induced dipole; weakerRank

13

__________ forces contribute to the solubility of ___ solutes and ____ solvents, but they are the ______ intermolecular force in solutions of _______ substances.

Dispersion; all; all; principal; nonpolar

14

Rank the following forces in order of decreasing strength (kJ/mol):

Dipole-dipole
H-bond
Dispersion
ion-dipole
dipole-induced dipole
ion-induced dipole

Ion-dipole (40-600)
H bond (10-40)
Dipole-dipole (5-25)
Ion-induced dipole (3-15)
Dipole-induced dipole (2-10)
Dispersion (0.05-40)

15

Salts are ______ in water. Why?

soluble; Like-Dissolves-Like Rule. The strong ion-dipole attractions between ion and water are similar to the strong attractions between ions and the strong H bonds between water molecules, so they CAN replace each other.

16

Salts are __________ in hexane (C6H14). Why?

insoluble; The weak ion-induced dipole forces between ion and nonpolar hexane CANNOT replace attractions between the ions.

17

Oil is _______ in water. Why?

insolube; The weak dipole-induced dipole forces between oil and water molecules CANNOT replace the strong H bonds within water molecules and the extensive dispersion forces within the oil.

18

Oil is __________ in hexane. Why?

soluble; The dispersion forces in one readily replace dispersion forces in the other.

19

The general formula for an alcohol

CH3(CH2)_nOH

20

Solubility in water is high for smaller alcohols. True or False?

True.

21

Table 13.2: Solubility of a Series of Alcohols in Water and in Hexane. Complete the chart.

Alcohol Sol. in H20 Sol. in Hexane

CH3OH
(methanol)

CH3CH2OH
(ethanol)

CH3(CH2)2OH
(1-propanol)

CH3(CH2)3OH
(1-butanol)

CH3(CH2)4OH
(1-pentanol)

CH3(CH2)5OH
(1-hexanol)

Table 13.2: Solubility of a Series of Alcohols in Water and in Hexane. Complete the chart.

Alcohol Sol. in H20 Sol. in Hexane

CH3OH <><> 1.2
(methanol)

CH3CH2OH <><> <><>
(ethanol)

CH3(CH2)2OH <><> <><>
(1-propanol)

CH3(CH2)3OH 1.1 <><>
(1-butanol)

CH3(CH2)4OH 0.30 <><>
(1-pentanol)

CH3(CH2)5OH 0.058 <><>
(1-hexanol)

22

Solubility in water is low for larger alcohols. Why?

While the -OH portionof such an alcohol forms H bonds to water, these cannot make up for all the other H bonds between water molecules that have to break to make room for the hydrcarbon portion.

23

Why is the solubility high for smaller alcohols?

When they mix with water, H bonding in solute and solven is replaced by H bonding between solute and solvent.

24

Solubility in hexane is _______ for the smallest alcohol. Why?

low; In addition to dispersion forces, weak dipole-induced dipole forces exist between the -OH of methanol (CH3OH) and hexane. These cannot replace the strong H bonding between CH3OH molecules, so its solubility is low.

25

Solubility in hexane is ______ for larger alcohols.

high

26

Which solvent will dissolve more:
Sodium chloride in methanol (CH3OH) or in 1-propanol (CH3CH2CH2OH)?

Methanol. NaCl is ionic, so it dissolves through ion-dipole forces. Both methanol and 1-propanol have a polar -OH group, but the hydrocarbon portion of each alcohol interacts only weakly with the ions and 1-propanol has a larger hydrocarbon than methanol.

27

Which solvent will dissolve more:
Ethylene glycol (HOCH2CH2OH) in hexane (CH3CH2CH2CH2CH2CH3) or in water?

Water.

28

Which solvent will dissolve more:
Diethyl ether (CH3CH2OCH2CH3) in water or in ethanol (CH3CH2OH)?

Ethanol

29

If similar intermolecular forces occur in solute and solvent, they replace each other when the substances mix and a ____ is likely to form. ("like dissolves like")

Solution

30

When _____ compounds dissolve in water, the ____ become surrounded by hydration shells of H-bonded water molecules.

ionic; ions

31

Solubility of organic molecules in various solvents depends on the relative sizes of their _____ and ______ portions.

polar; nonpolar

32

The solubility of nonpolar gases in water is low because of ____ intermolecular forces. Gases are _____ with one another, and they ______ in solids by fitting into spaces between the closely packed particles.

weak; miscible; dissolve

33

Solid-solid solutions include ______ and ______.

alloys; waxes