chapter 8: Gases

Question 1

what are the percentages of gases in the air

Answer 1

N2 = 78
O2 = 21

Question 2

the air we breathe is a…

Answer 2

mixture of gases

Question 3

what are some characteristics of gases

Answer 3

• Spontaneously expand to fill their containers (no outside energy)
• highly compressible
• homogenous mixture
• low density

Question 4

what happens when the gas particles collide with each other

Answer 4

creates pressure

Question 5

what is pressure

Answer 5

force that results from the collisions
of gas particles divided by the area of the surface
with which they collide

Question 6

what is the formula for pressure

Answer 6

P = F/A
force = m x a

Question 7

what does pressure depend on

Answer 7

of gas particles

Question 8

fewer gas particles =

Answer 8

lower pressue

Question 9

how does altitude affect pressure

Answer 9

pressure decreases above 30 k

- keep cabins pressurized

Question 10

how does gravity affect the atomosphere

Answer 10

causes the atmosphere as a whole to press down on earth

Question 11

what is atmospheric pressure

Answer 11

weight of air per unit of area

Question 12

what is the si unit for force

Answer 12

newton (N)

Question 13

what is the SI unit of pressure

Answer 13

N/m^2 or pascal (Pa)

Question 14

who was pascal named after

Answer 14

Blaise Pascal

Question 15

what is bar

Answer 15

used to report pressure; 10^5 Pa

Question 16

who discovered atm,torr, mmhg

Answer 16

evangelista torricelli ( Galileo’s student)

Question 17

who invented the mercury barometer

Answer 17

torricellu

Question 18

what is standard atomospheric pressure

Answer 18

pressure @ sea lvl

Question 19

what is the standard atms. press.

Answer 19

101325 Pa or 101.325 kPa

Question 20

what non si units are w/ the atmospheric pressure

Answer 20

atm, mmhg m torr

Question 21

what is a mamometer

Answer 21

measure pressure of enclosed gases

Question 22

what did robert boyle do

Answer 22

investigated the relationship between the pressure

of a gas and its volume.

Question 23

what was boyle’s law

Answer 23

volume and pressure are inverse @ constant temp

Question 24

boyle’s law formula

Answer 24

P1V1 = P2V2

Question 25

what did jacques charles do

Answer 25

discovered relationship between volume and temp

Question 26

what was charles law

Answer 26

volume and temp are proportional @ maintained pressure

Question 27

charles law formula

Answer 27

V1/T1 = V2/T2

Question 28

what did gay lussac do and who was he

Answer 28

discovered relationship between gas and volume | law of combining volumes

Question 29

what is the law of combining volumes

Answer 29

given P and T, the Vs of gases that react with one another are in the ratios of small whole numbers example: wo volumes of H2 gas react with one volume of O2 gas to form two volumes of water vapor.

Question 30

avogadro's hypothesis

Answer 30

equal volumes of gases at the same temp and pressure have equal # of molecules

Question 31

what are stp conditions

Answer 31

22.4 L 0 degrees celcius 1 atm

Question 32

22.4 L =

Answer 32

6.022 x 10^23 molecules = 1 mol

Question 33

avogadro's law

Answer 33

volume is directly proportional to # of moles | (temp, pressure = constant_

Question 34

what is the ideal gas equation

Answer 34

pv = nrt

Question 35

what is an ideal gas

Answer 35

hypothetical gas whose pressure, volume, and temperature behavior is completely described by the ideal-gas equation.

Question 36

what does R = in pvnrt

Answer 36

0.08206 L-atm/mol K

Question 37

avogadro's law formula

Answer 37

V1/n1 = V2/n2

Question 38

pressure volume and temp formula

Answer 38

P1V1/T1 = P2V2/T2

Question 39

what is the formula for density

Answer 39

d = m/V

Question 40

moles per unit of volume =

Answer 40

P /RT

Question 41

what is the formula for partial pressure

Answer 41

P = n1RT/V

Question 42

what does p total =

Answer 42

RT/V

Question 43

mole fraction x

Answer 43

n1/ntotal | P1 = (n1/ntotal)Ptotal = X1Ptotal

Question 44

how is gas collected

Answer 44

through water displacement

Question 45

what does vapor pressure depend on

Answer 45

temp

Question 46

what does the ideal gas law show and what does it lack

Answer 46

how gases behave but doesn't explain why they behave like that

Question 47

kinetic molecular theory describes...

Answer 47

model to help us picture what happens to gas particles as experimental conditions change.

Question 48

what is the kinetic molecular theory

Answer 48

1. ) volume = zero 2. ) particles in constant motion 3. ) particles have no force

Question 49

gases in the same container have the same temp....

Answer 49

have the same average kinetic enegy

Question 50

lighter particles =

Answer 50

faster average velocity

Question 51

as temp increases

Answer 51

average velocity increases

Question 52

what is diffusion

Answer 52

spread of a substance throuhout a space or second substance

Question 53

what direction do gas molecules travel in

Answer 53

straight line

Question 54

mean free path

Answer 54

avg distance a molecule travels between collisions

Question 55

mean free path decreases as

Answer 55

pressure increases Black Friday = Crowded = high pressure = short distance before bumping into someone = short mean free path ‒ Mall after closing = low pressure = long distance before bumping into someone = long mean free path

Question 56

effusion

Answer 56

escape of gas molecule through tiny hole

Question 57

characteristics of ideal gas law

Answer 57

- no attraction between has molecules | - gas molecules do not take up space

Question 58

what conditions are ideal gas laws valid in

Answer 58

high temp low pressure

Question 59

what is van de waals equation

Answer 59

n^2a/ V2