Chapter 10

Question 1

phase change

Answer 1

transition from state of matter to another

the stronger the forces between particles, the greater the energy required to change phase

Question 2

ionic substances

Answer 2

packed into lattices: rigid frameworks of atoms, molecules, or ions.
bc the interactions between ions are so strong it takes a great amount of energy to disrupt the lattice. as a result, they tend to have a high melting point

Question 3

metallic substances

Answer 3

-form lattices of tightly packed atoms and electrons move easily between atoms, because of this property, metals -are good conductors of electricity
-metal lattice is not as rigid bc the neutral atoms dont pack together as closely as the oppositely charged ones do
-shapes of metals are easily altered (malleable and ductile)
moderate melting points

Question 4

molecular substances

• forces within molecules
• forces between molecules

Answer 4

-covalent bonds
-intermolecular forces
which are much weaker and as a result molecular compounds have lower melting and boiling points than ionic compounds, though they depend on the strength of the intermolecular forces

Question 5

covalent networks

Answer 5

lattices of covalent bonds that form giant molecules

Question 6

polymers

Answer 6

contain long chains of covalently bonded atoms

Question 7

intermolecular forces

-dipole-dipole interactions

Answer 7

attractions between polar covalent molecules

higher melting and boiling points bc it takes more energy to pull them apart

Question 8

intermolecular forces
special type of dipole-dipole interactions
-hydrogen bonding

Answer 8

a strong intermolecular force between molecules containing H-F, H-O, or H-N bonds

Question 9

intermolecular forces

-london dispersion forces

Answer 9

weak intermolecular forces that result from instantaneous dipoles

Question 10

ideal gas

Answer 10

ideal gas has 2 properties:

1) the volume of the particles is much less than that of the container
2) particles have no attraction for eachother

Question 11

pressure

Answer 11

the force that particles exert on their surroundings

pressure = force/area

Question 12

standard pressure

Answer 12

average air pressure at sea level

760 mm Hg / 760 torr

Question 13

Boyles law

Answer 13

describes the relationship between the pressure and volume of a gas
the pressure and volume of a gas are inversely related
PV = constant, P1V1=P2V2

Question 14

Charles law

Answer 14

states that at a constant pressure, the volume of a gas is directly proportional to its temperature
V~T, V/T = constant
V1/T1=V2/T2
temperature has to be in kelvins to get correct answer

Question 15

absolute zero

Answer 15

-273.15*C

Question 16

the combined gas law

Answer 16

P1V1/T1 = P2V2/T2

temperatures must be expressed in kelvins

Question 17

Avogadro’s law

Answer 17

If the temperature and pressure are constant, the volume of a gas is proportional to the number of moles of gas present
V~n
one mole of gas occupies 22.4 liters of gas

Question 18

Standard temperature and pressure (STP)

Answer 18

T=0*C (273 kelvins), P=1.0 atm

Question 19

The ideal gas law

Answer 19

PV= nRT
n- number of moles of gas
R- a constant = to 0.0821 L*atm/mol*K
T must be in kelvins
P, V must match gas constant

Question 20

Diffusion

Answer 20

the spread of particles through random motion

Question 21

effusion

Answer 21

the process of gas escaping from a container

smaller particles move faster, more likely to encounter ways out and leak out faster