Chemistry - Chapter 13 Flashcards Preview

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Flashcards in Chemistry - Chapter 13 Deck (51):
1

kinetic energy

the energy an object has because of its motion

2

kinetic theory

all matter consists of tiny particles that are in constant motion

3

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

4

How does kinetic theory explain gas pressure?

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

5

gas pressure

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

6

vacuum

an empty space with no particles and no pressure

7

atmospheric pressure

the collisions of atoms and molecules in air with objects

8

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

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

9

barometer

device used to measure atmospheric pressure

10

what does atmospheric pressure depend on?

weather and altitude

11

pascal (Pa)

what does it represent?

SI unit of pressure

represents a very small amount of pressure

12

what are the 3 mathematical conversions?

1 atm = 760mm Hg = 101.3kPa

13

standard atmosphere (atm)

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

14

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

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

15

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

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

16

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

they are directly related to each other

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

17

what is absolute zero? (3)

(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

18

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

why?

liquids and solids

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

19

what is the relationship between evaporation and kinetic energy?

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

20

vaporization

the conversion of a liquid to a gas or vapor

21

evaporation

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

22

vapor pressure

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

23

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

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

24

what happens to the particles in equilibrium?

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.

25

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

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

26

volatile

how easy it will melt

27

what liquid is the most / least volatile?

most = diethyl

least = water

28

what is used to measure vapor pressure?

manometer

29

under what conditions does boiling occur?

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

30

boiling point

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

31

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

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

32

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

boiling points decrease at higher altitudes

33

at a lower external pressure...?

the boiling point decreases

34

at a higher external pressure...?

the boiling point increases

35

what kind of a process is boiling?

a cooling process

36

normal boiling point

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

37

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

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

38

melting point

the temp. at which a solid changes into a liquid

39

freezing point

the temp. at which a liquid changes into a solid

40

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

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

41

crystal

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

42

unit cell

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

43

allotropes (3)

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

44

amorphous solid

lacks an ordered internal structure

atoms are randomly arranged

45

glass

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.

46

when can sublimation occur?

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

47

sublimation

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

48

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

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

49

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

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

50

phase diagram

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

51

triple point

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