Chapter 11- Liquids and Ch 12- Solids

Solids have ___ Kinetic energy

low

Solids have ___ attraction

high

liquids have ___ kinetic energy

an equilibrium of

liquids have ___ attraction

an equilibrium of

gases have ____ kinetic energy

high

gases have ___ attraction

low

what must molecules do for a liquid to boil?

they must overcome the attraction from nearby molecules

high attraction = ____ boiling point = _____ for the molecules to break free

high; harder

Intramolecular bonds

covalent bonds

intramolecular bonds have _____ attraction

stronger

intermolecular bonds

between separate molecules

intermolecular bonds have _____ attraction

weaker

from coulomb’s law, we can tell this about intramolecular forces

stronger, shorter distances, usually full charges or strong electron sharing

from coulomb’s law, we can tell this about intermolecular forces

weaker, longer distances, usually partial charges

Van der Waals IMFs include

London dispersion force and dipole-dipole force

order the IMFs from weakest to strongest

1. LDF (london dispersion)

2. D-D (dipole-dipole)

3. Hbond (hydrogen bond)

4. I-d (ion-dipole)

which force(s) can only be associated with ionic or non-neutral particles?

ion-dipole

which force is found in all molecules/atoms?

LDF

an LDF can best be described as

a temporary imbalance in the e- cloud

how does LDF create a dipole?

it’s instantaneous and occurs when the e-’s just so happens to be on the same side, causing a slightly more negative side and the nearby atom/molecule’s protons to be attracted to it

True or false: LDF’s can occur at long distances

false; only at short distances!

what is polarizability?

the distortion of the e- cloud

the _____ e-, the ____LDF

more; more

T/F: a molecule with a larger mass has a greater LDF compared to one with a smaller mass

True!

a molecule has a stretched-out (linear) shape! what happens to its LDF?

greater LDF

a molecule has a spherical shape! what happens to its LDF?

lesser LDF

which has a higher boiling point? butane (C4H10) or hexane (C6H14)?

hexane!

why does hexane have a higher bp than butane?

more mass!

isomers share

the same formula

isomers differ in

arrangement and properties

what’s true about an isomer/s molecular weight?

they’re the same!

rank from lowest to highest bp

dimethylpropane, methyl butane, pentane

why does methyl butane have a higher bp than dimethylpropane although they have a similar molar mass?

it has a more linear shape

in dipole-dipole interactions, what is true about a dipole?

they are polar molecules with a more negative and a more positive end

negative and positive ends of a dipole are repelled or attracted?

attracted

the same charges of a dipole are repelled or attracted?

repelled

in D-D interactions, molecules with a similar mass and molar size/shape (LDF factors) have a higher bp when they are more

polar

what’s more important in considering IMFs: D-D or LDFs?

D-D if molecules are roughly the same size/shape; LDF if molecule is much larger than the other

These two molecules have the same molar mass and roughly similar shapes. Which has a higher boiling point, and why?

acetone; it is more polar than methylpropane

which has a higher bp and why: ClCH₂CH₂Cl or CHCl₂CH₃

CHCl₂CH₃ because it has a greater dipole shift

in Hbonds, what will hydrogen be attracted to?

N, O, F

why do Hbonds form highly polar bonds?

due to the high electronegativities of N, O, and F

T/F: in order for a hydrogen bond to happen, F-H, O-H, or N-H bond in one molecule forms a H bond with F, O, or N in another molecule

true!

in an Hbond, what does the H on the first molecule have to interact with on the second molecule?

a lone pair of the second molecule

real-life examples of how Hbonds are important!

• stabilize protein structures

• forms ice rings

• forms DNA double helix

Which will have a higher boiling point, and why?

acetic acid; has more hydrogen bonds

Which of these will have a higher BP? Why?
 CH₃Cl or CH₃Br

CH₃Br; higher molar mass

Which of these will have a higher BP? Why?
CH₃CH₂OH or CH₃OH

CH₃CH₂OH; molar mass, more spread out

(CH₃)₂NH or (CH₃)₃N, what has the higher bp?

(CH₃)₂NH; can form a hydrogen bond

Which of the following substances experiences…

The strongest dipole-dipole interactions?

1. H₂NNH₂

2. H₂CCH₂

3. Ne

4. CH₃CH₂CH₂CH₂CH₃

H₂NNH₂

Which of the following substances experiences…

The largest London dispersion forces?

1. H₂NNH₂

2. H₂CCH₂

3. Ne

4. CH₃CH₂CH₂CH₂CH₃

CH₃CH₂CH₂CH₂CH₃

Which of the following substances experiences…

The lowest boiling point?

1. H₂NNH₂

2. H₂CCH₂

3. Ne

4. CH₃CH₂CH₂CH₂CH₃

Ne; smallest mass, single atom

ion-dipole forces give good insight on how…

ionic compounds dissolve in water

ion-dipole explained

negative end of polar liquid is attracted to positive end of ion; positive end of polar liquid is attracted to negative end of ion