Chapter 11 States of Matter Liquids and Solids

Question 1

Gases according to Kinetic Molecular Theory

Answer 1

are composed of molecules or single atoms that are in constant random motion throughout mostly empty space ( unless the gas is highly compressed). A gas is easily compressed because the molecules can be pushed into a smaller space. A gas is fluid because individual molecules can move easily relative to one another.

Question 2

Liquids according to Kinetic Molecular Theory

Answer 2

Liquids are relatively incompressible fluids. The molecules of a liquid are in constant random motion (as in a gas) but are more tightly packed, so there is much less free space. Molecules can move relative to one another as in a gas, a liquid can flow (it is fluid). A liquid is nearly incompressible.

Question 3

Solids according to Kinetic Molecular Theory

Answer 3

Solids are nearly incompressible and tea rigid, not fluid. The particles making up a solid ( which may be atoms, molecules, or ions) exist in close contact and (unlike those in a gas or liquid) do not move about but oscillate or vibrate about fixed sites. This explains the rigidity of a solid. The compact structure explains its incompressibility.

Question 4

Melting

Answer 4

is the change of a solid to the liquid state ( melting is also referred to as fusion).

Question 5

Freezing

Answer 5

is the change of a liquid to the solid state.

Question 6

Vaporization

Answer 6

is the change of a solid or a liquid to the vapor.

Question 7

Sublimation

Answer 7

the change of a solid directly to the vapor.

Question 8

Condensation

Answer 8

is the change of a gas to either the liquid or the solid state (the change of vapor to solid is sometimes called deposition).

Question 9

Vapor Pressure

Answer 9

of a liquid is the partial pressure of the vapor over the liquid, measured at equilibrium at a given temperature.

Question 10

Process of dynamic equilibrium involving vaporization of a liquid and condensation of its vapor.

Answer 10

as the number of molecules in the vapor state increases, more and more gaseous molecules collide with the liquid water surface, exerting pressure. The molecules in the vapor collide with the liquid surface and stick, as the number of molecules in the volume of vapor increases until the rate at which the molecules are condensing on the liquid equals the rate at which molecules are vaporizing.

Question 11

Boiling Point

Answer 11

the temperature at which the vapor pressure of a liquid equals the pressure exerted on the liquid (atmospheric pressure, unless the vessel containing the liquid is closed).

Question 12

Phase Diagram

Answer 12

is a graphical way to summarize the conditions under which the different states of a substance are stable.

Question 13

Triple Point

Answer 13

is the point on a phase diagram representing the temperature and pressure at which three phases of a substance coexist in equilibrium.

Question 14

Critical Temperature

Answer 14

the temperature above which the liquid state of a substance no longer exists regardless of pressure.

Question 15

Critical Pressure

Answer 15

is the minimum pressure that must be applied to a gas at the critical temperature to liquefy it.

Question 16

Critical Point

Answer 16

a point at which the temperature and pressure have their critical values.

Question 17

Surface Tension

Answer 17

is the energy required to increase the surface area of a liquid by a unit amount.

Question 18

Viscosity

Answer 18

is the resistance to flow that is exhibited by all liquids and gases. The viscosity of a liquid can be measured by the time it takes for a given to flow through a capillary tube.

Question 19

Intermolecular Forces

Answer 19

the forces of interaction between molecules.

Question 20

Intermolecular Forces and the Properties of Liquids

Answer 20

Normal boiling points are approximately proportional to the energy of intermolecular attraction. Normal boiling points are lowest for liquids with weak intermolecular forces. Surface tension, to increase the surface area it is necessary to pull molecules apart against the intermolecular forces of attraction. Surface tension is expected to increase with the strength of attractive forces/molecular mass. The viscosity of a liquid depends in part on IMFs , increasing the attractive forces between molecules increases the resistance to flow.

Question 21

Hydrogen Bonding

Answer 21

is a weak to moderate attractive force that exist between a hydrogen atom covalently bonded to a very electronegative atom, and lone pair of electrons on another small electronegative atom.

Question 22

Molecular Solid

Answer 22

is a solid that consists of atoms or molecules held together by IMFs. Exs: solid neon, solid water (ice) and solid carbon dioxide (dry ice).

Question 23

Metallic Solid

Answer 23

is a solid that consists of positive cores of atoms held together by a surrounding sea of electrons. Exs: iron, copper, and silver.

Question 24

Ionic Solid

Answer 24

is a solid that consists of cations and anions held together by the electrical attraction of opposite charges (ionic bonds) Exs: cesium, chloride, sodium chloride, and zinc sulfide.

Question 25

Covalent Network Solid

Answer 25

is a solid that consists of atoms held together in large networks or chains by covalent bonds. Exs: diamond (3 dimensional), graphite (sheets), and asbestos (chains).

Question 26

Simple Cubic Unit

Answer 26

is a cubic unit cell in which lattice points are situated only at the corners.

Question 27

Body-Centered Cubic Unit

Answer 27

is a cubic unit cell in which there is a lattice point at the center of the cubic cell in addition to those at the corners.

Question 28

Face-Centered Cubic Unit Cell

Answer 28

is a cubic unit cell in which there are lattice points at the centers of each face of the unit cell in addition to those at the corners.