Chemistry - Chapter 13

Question 1

kinetic energy

Answer 1

the energy an object has because of its motion

Question 2

kinetic theory

Answer 2

all matter consists of tiny particles that are in constant motion

Question 3

what are the three assumptions of the kinetic theory as it applies to gases? (3)

Answer 3

1. the particles in a gas are considered to be small, hard spheres with an insignificant volume
2. the motion of the particles in a gas is rapid, constant, and random
3. all collisions between particles in a gas are perfectly elastic

Question 4

How does kinetic theory explain gas pressure?

Answer 4

gas pressure is the result of billions of rapidly moving particles in a gas simultaneously colliding with an object

Question 5

gas pressure

Answer 5

results from the force exerted by a gas per unit surface area of an object

Question 6

vacuum

Answer 6

an empty space with no particles and no pressure

Question 7

atmospheric pressure

Answer 7

the collisions of atoms and molecules in air with objects

Question 8

what happens to the atmospheric pressure if elevation went up? down? (2)

Answer 8

up = atmospheric pressure decreases b/c the density of Earth’s atmosphere decreases as the elevation increases

down = atmospheric pressure increases b/c the density of Earth’s atmosphere increases as the elevation decreases

Question 9

barometer

Answer 9

device used to measure atmospheric pressure

Question 10

what does atmospheric pressure depend on?

Answer 10

weather and altitude

Question 11

pascal (Pa)

what does it represent?

Answer 11

SI unit of pressure

represents a very small amount of pressure

Question 12

what are the 3 mathematical conversions?

Answer 12

1 atm = 760mm Hg = 101.3kPa

Question 13

standard atmosphere (atm)

Answer 13

the pressure required to support 760mm of mercury in a mercury barometer at 25 degrees Celcius

Question 14

what is the standard temperature and pressure (STp) are defined as…?

Answer 14

a temp. of 0 degrees Celcius and a pressure of 101.3kPa, or 1 atm

Question 15

what is the relationship between the temperature in kelvins and the average kinetic energy of particles?

Answer 15

the Kelvin temperature of a substance is directly proportional to the average kinetic energy of the particles of the substance

Question 16

Relationship between the average kinetic energy of the particles and the substance’s temperature?

Answer 16

they are directly related to each other

• increase in average kinetic energy of the particles cause the temp. of a substance to rise

Question 17

what is absolute zero? (3)

Answer 17

(0 K, or -273.15 degrees Celsius)

the temp at which the motion of particles theoretically ceases

no temp. can be lower than absolute zero

Question 18

what states of matter are known as condensed states of matter? (2)

why?

Answer 18

liquids and solids

b/c increasing pressure on either of them will have little to no effect on them

Question 19

what is the relationship between evaporation and kinetic energy?

Answer 19

during evaporation, only those molecules with a certain minimum kinetic energy can escape from the surface of the liquid

Question 20

vaporization

Answer 20

the conversion of a liquid to a gas or vapor

Question 21

evaporation

Answer 21

vaporization that occurs at the surface of a liquid that is not boiling

Question 22

vapor pressure

Answer 22

a measure of the force exerted by a gas above a liquid

Question 23

when can a dynamic equilibrium exist between a liquid and its vapor?

Answer 23

in a system at constant vapor pressure, a dynamic equilibrium exists between the vapor and the liquid

the system is in equilibrium because the rate of evaporation of liquid equals the rate of condensation of vapor

Question 24

what happens to the particles in equilibrium?

Answer 24

the particles in the system continue to evaporate and condense, but no net charge occurs in the number of particles in the liquid or vapor.

Question 25

what will happen when there is a rise in the temperature of a contained liquid?

Answer 25

an increase in vapor pressure, b/c the particles in the warmed liquid have increased kinetic energy

Question 26

volatile

Answer 26

how easy it will melt

Question 27

what liquid is the most / least volatile?

Answer 27

most = diethyl least = water

Question 28

what is used to measure vapor pressure?

Answer 28

manometer

Question 29

under what conditions does boiling occur?

Answer 29

when a liquid is heated to a temperature at which particles throughout the liquid have enough kinetic energy to vaporize, the liquid begins to boil

Question 30

boiling point

Answer 30

the temp. at which the vapor pressure of the liquid is just equal to the external pressure on the liquid

Question 31

what happens to a liquid in an open container? (3)

Answer 31

the rate of evaporation increased as heat is applied heating allows a greater number of particles to overcome the attractive forces that keep them in the liquid state average kinetic energy increases and the temp. rises

Question 32

b/c atmospheric pressure is lower at high altitudes...?

Answer 32

boiling points decrease at higher altitudes

Question 33

at a lower external pressure...?

Answer 33

the boiling point decreases

Question 34

at a higher external pressure...?

Answer 34

the boiling point increases

Question 35

what kind of a process is boiling?

Answer 35

a cooling process

Question 36

normal boiling point

Answer 36

the boiling point of a liquid at a pressure of 101.3kPa

Question 37

Difference b/t crystalline structure of diamond and graphite? (2)

Answer 37

Diamond = each carbon atom in the interior of the diamond is strongly bonded to 4 others and the array is rigid and compact Graphite = has carbon atoms that are linked in widely spaced layers of hexagonal arrays

Question 38

melting point

Answer 38

the temp. at which a solid changes into a liquid

Question 39

freezing point

Answer 39

the temp. at which a liquid changes into a solid

Question 40

the melting and freezing points of a substance are... (2)

Answer 40

at the same room temp. At that temp., the liquid and solid phases are in equilibrium

Question 41

crystal

Answer 41

the particles are arranged in an orderly, repeating, 3-D pattern called a lattice

Question 42

unit cell

Answer 42

the smallest group of particles within a crystal that retains the geometric shape of the crystal

Question 43

allotropes (3)

Answer 43

two or more molecular forms of the same element in the same physical state composed of atoms of the same element but we have different properties b/c of diff. structures

Question 44

amorphous solid

Answer 44

lacks an ordered internal structure atoms are randomly arranged

Question 45

glass

Answer 45

a transparent fusion product of inorganic substances that have cooled to a rigid state without crystallizing * doesn't melt, it gradually heats up and softens.

Question 46

when can sublimation occur?

Answer 46

in solids with vapor pressures that exceed atmospheric pressure at or near room temperature

Question 47

sublimation

Answer 47

the change of a substance from a solid to a vapor without passing through the liquid state

Question 48

which type of solid is likely to have the lowest melting point -- an ionic solid or a molecular solid? Explain.

Answer 48

a molecular solid b/c the attractive forces holding them together are weak

Question 49

how are the conditions at which phases are in equilibrium represented on a phase diagram?

Answer 49

the conditions of pressure and temperature at which two phases exist in equilibrium are indicated on a phase diagram by a line separating the two regions representing the phases

Question 50

phase diagram

Answer 50

gives the conditions of temperature and pressure at which a substances exists as a solid, liquid, or gas (vapor)

Question 51

triple point

Answer 51

describes the only set of conditions at which all of the three phases can exist in equilibrium with one another