Unit 2 - Gas Flashcards Preview

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Flashcards in Unit 2 - Gas Deck (74):
1

Gasses are compressible; meaning what?

That pressure increases as volume decreases..

2

Why do gasses expand as temperature increases?

The more heat; the more space is taken up because they move faster and more often and farther

3

When a gas is confined what happens when the temperature increases

the pressure increases

4

when a gas is not confined what happens when temperature increases

the volume/amount of space the gas takes up increases

5

gasses have low densities meaning what

very low physical weight, weigh like nothing

6

gasses are miscible; meaning what

they mix evenly and completely, so the CO2 spreads evenly throughout the world and there isnt more Co2 in some places compared to others

7

gasses have no shape or volume what do they do

they take the shape of the container they are in

8

what does the Kinetic Molecular Theory say

all particles are in motion at all times

9

what is an ideal gas

hypothetical gas that has perfect characteristics

10

characteristics of an ideal gas

-gas molecules are in constant random motion that moves in a straight line until they bounce back off the wall of a container or molecule (they go back and forth in a straight line bouncing off things)
-gas molecules have a mass but no volume
-the only interaction between gas and container are collisions where kinetic energy is conserved

11

what are point masses

they have a mass but no volume
IDeAL GASSES have A POINT MASS

12

what are elastic collisions

collisions where kinetic energy is conserved IDEAL GASSES HAVE ELASTIC COLLISIONS

13

real gasses do not have these perfect characteristics however

their behaviour is not that different from an ideal gas

14

real gasses slow down over time; why?

because of friction; instead of bouncing back and forth at a constant rate and force like ideal gasses, over time after each bounce the gas loses force and slows down

15

friction is not involved in what gasses

ideal gasses

16

what creates our atmosphere

the earths gravitational pull keeps gas molecules near the surface of the planet

17

what is pressure

force per unit area... force/area

18

pressure is exerted where and how much

in all directions to the same extent

19

what is atmospheric pressure

force that air exerts in a particular area on the Earths surface

20

air is less compressed as ...

altitude increases (the height) the higher you get air is less compressed

21

because air is less compressed the higher you go that means...

less pressure is exerted the higher you get

22

Pascal and Perier used Hg to prove ...

atmospheric pressure decreases with altitude

23

the work of pascal, perier and torricelli all led to the development of

the mercury barometer

24

what are the several different units used to measure pressure

mmHg or torr
Pa
kPa
atm
bar

25

whats mmhg or torr

millimeters of mercury; (760)

26

whats kPa and Pa

pascal and kilopascal.. kPa is 101.325

27

whats atm

atmospheric pressure ; (1)

28

1 bar = how many kPa

100

29

how to convert

w/g = w/g.. multiply first bottom by second top and divide by second bottom to get first top.. then use sig digs

30

who discovered boyles law

irish scientist robert boyle

31

what was robert boyle studying

relationship between pressure and volume of gases at constant temperatures

32

pressure on the walls of a container is caused by

collisions of gas molecules with the walls

33

as you reduce the volume of contained gas (make the container smaller), there is less room what happens

they collide with the walls more .. more collisions = higher pressure

34

_____ collisions = _______ pressure

more = higher

35

boyles law graph ; volume vs pressure for a gas graph... how does it work

title: volume vs pressure for a gas
Y axis: responding (volume L)
x axis: manipulated (pressure kPa)
THE LINE GOES DOWN FROM LEFT TO RIGHT
BAD BOYLE = GOES DOWN

36

boyles law states

the volume of gas varies inversely with the pressure at a constant temperature and mass... PRESSURE AND VOLUME CHANGE: TEMP AND MASS STAY SAME

37

examples of boyles law

breathing/lungs; inhale we increase the volume of our chest with decreases pressure allowing more air to move in...
the deeper in the ocean you go the more pressure is around you which makes you want to breath out

38

BOYLES LAW EQUATION

P1V1=P2V2
Pressure= kPa
Volume= L

39

GRAphing volume vs temperature

goes up from left to right; linear.
Title: volume vs temperature for a gas
Y axis: Volume (L)
X axis: Temperature in K or C
***When the temp is in K the line starts at the corner of the graph at 0K but when in C it starts farther up because there are negatives in C it would start at -273.15C and go up from there

40

the temperature is what when the volume of a gas is zero

-273.15C which is 0 Kelvin

41

what is absolute zero

0 Kelvin and -273.15 Celcius

42

WHo created absolute zero

Lord Kelvin in 1848

43

t is used for temperature in _____
T is used for temperature in ____

t = C
T = K

44

how do you go from C to K

you add 273.15 to your Celcius number.. aka 25C + 273.15 = 298.15K

45

how do you go from K to C

you subtract 273.15 from your Kelvin number.. aka 298.15K - 273.15 = 25C

46

Who noticed there was a relationship between temperature and volume of gas

Jacques Charles and Joseph Louis Gay-Lussac

47

Charles law stuff: as temperature increases so does..

the kinetic energy of the gas molecules

48

charles law stuff: as molecules move faster, they...

exert higher pressure

49

charles law stuff: the volume of a gas will expand under this pressure until it reaches

atmospheric pressure

50

charles law states

that the volume of gas varies directly with the temperature at a constant pressure and mass.. VOLUME AND TEMPERATURE CHANGE AND PRESSURE AND MASS ARE CONSTANt

51

whats constant in charles law

pressure and mass

52

what changes in charles law

volume and temperature

53

whats constant in boyles law

temperature and mass

54

what changes in boyles law

volume and pressure

55

CHarles LAW EQUATION

V1/T1=V2/T2
T= temp. in K
V= Volume in L

56

how do you go from mL to L

mL#/1000 = L

57

whats STP

standard pressure and temperature
=0C/273.15K and 101.325 kPa

58

Whats SATP

standard ambient temperature and pressure
=25C/298.15K and 100 kPa

59

Equation for Combined Gas LAw (charles and boyles combined)

(P1)(V1)/T1 = (P2)(V2)/T2
pressure in kPa
Volume in L
Temp in K

60

who studied combining volumes of gases

Gay-Lussac

61

About Combining volumes of gases

-chemical reactions involving gases
-studied the volumes og gas reactants and products
-gases combine in very simple proportions

62

the law of combining volumes states

that when gases react, the volumes of the gaseous reactants and products measured at constant temperature and pressure are always in whole number ratios

63

Equation for combining volumes of gases

V1/N1 = V2/N2
v1 is the volume given
n1 would be the number of mols of the gas with the given volume
v2 would be the volume your looking for
n2 is the number of moles of the gas your looking for

64

example of law of combining volumes

n2 + 3h2 -> 2nh3
1:3:2 is the ratio
for every one mole of nitrogen gas and 3 moles of hydrogen gas , 2 moles of ammonia gas is produced

65

whats the ideal gas law

combines all four variables P, V n and T into one equation

66

Ideal Gas Law Equation

PV =nRT
pressure in kpa
volume in L
n= number of moles in mol
R=universal gas constant (8.314)
Temperature in K

67

ammonia

NH3

68

ozone equation

O3

69

sucrose

C12H22O11

70

methane

CH4

71

glucose

C6H12O6

72

hydrogen sulphide formula

H2S

73

ethane

C2H6

74

methanol

CH3OH