chem 106 quiz 1

Question 1

properties of a gas

Answer 1

no fixed shape
no fixed volume
compressible
diffusion rapid

Question 2

properties of liquids

Answer 2

no fixed shape
fixed volume
incompressible
diffusion slower

Question 3

properties of solids

Answer 3

fixed shape
fixed volume
incompressible
molecules locked in place (bonds)
diffusion extremely slow

Question 4

boiling points can indicate

Answer 4

the strength of the intermolecular attractive force

Question 5

ΔHfusion represents the phase change from

Answer 5

solid > liquid

Question 6

ΔHvaporization represents the phase change from

Answer 6

liquid > gas

Question 7

which is typically larger? ΔHfusion or ΔHvaporization? why?

Answer 7

ΔHvaporization because completely breaking attractive forces

Question 8

intermolecular forces (from strongest to weakest)

Answer 8

ion-dipole
dipole-dipole (Hydrogen bonding)
dispersion

Question 9

all molecules have ? forces

Answer 9

dispersion; strongest for nonpolar tho

Question 10

? molecules have dipole-dipole forces

Answer 10

polar

Question 11

ion-dipole forces are present in

Answer 11

mixtures of ionic compounds and polar compounds

Question 12

surface tension and viscosity are affected by

Answer 12

intermolecular forces

Question 13

dispersion forces are always weak in ? molecules but can be significant in molecules with ?

Answer 13

small; higher molar mass

Question 14

Hydrogen bonds are present in molecules containing

Answer 14

hydrogen bonded directly to fluorine, oxygen, or nitrogen (but remember - hydrogen bonds are intermolecular/external)

Question 15

the higher the temperature, the (lower/higher) the average kinetic energy of the collection of molecules

Answer 15

higher

Question 16

ΔHvaporization is always (negative/positive) because the process is (endothermic/exothermic)

Answer 16

positive; endothermic

Question 17

ΔHcondensation is always (negative/positive) because the process is (endothermic/exothermic)

Answer 17

negative; exothermic

Question 18

boiling point

Answer 18

the temperature at which the liquid’s vapor pressure equals the external pressure

Question 19

normal boiling point

Answer 19

the temperature at which its vapor pressure equals 1 atm

Question 20

Clausius-Clapeyron equation

Answer 20

ln(P2/P1) = ( - ΔHvap / R) * ( 1/T2 - 1/T1)

Question 21

the boiling point increases with increasing ? because of the high ?

Answer 21

ΔHvap; intermolecular forces

Question 22

the pressure of vaporization (decreases/increases) with increasing IMFs and BP

Answer 22

decreases

Question 23

reaction rates double every

Answer 23

10*C

Question 24

solid to liquid

Answer 24

melting

Question 25

liquid to solid

Answer 25

freezing

Question 26

liquid to gas

Answer 26

vaporization

Question 27

gas to liquid

Answer 27

condensation

Question 28

gas to solid

Answer 28

deposition

Question 29

solid to gas

Answer 29

sublimation

Question 30

examples of crystalline solids

Answer 30

salt, diamond

Question 31

examples of amorphous solids

Answer 31

glass, plastic, rubber

Question 32

unit cell

Answer 32

smallest repeating unit from which you can build the whole crystal

Question 33

cubic unit cell

Answer 33

cube with atoms on the vertices; 1 atom per unit cell

Question 34

body centered cubic

Answer 34

cube with atoms on the vertices and one in the center; 2 atoms per unit cell

Question 35

face centered cubic

Answer 35

cube with atoms on the vertices and in the centers of the faces; 4 atoms per unit cell (most efficient packing)