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8/13/2019 Ideal Gas Law PPT
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Ideal Gas Law
PV=nRT
8/13/2019 Ideal Gas Law PPT
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Remember
Boyles Law
Charles Law:
Combined Gas Law:(Units MUST Match
Temp in Kelvin!!!)
2
2
1
1
T
V
T
V
2
22
1
11
T
VP
T
VP
2211 VPVP
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A gas with a volume of 350 ml is collected
at 15o C and 120 kPa. If the temperature
changes to 30o
C, what pressure would berequired to put this gas in a 300 ml
container?
K
mlP
K
mlkPa
303
300
288
350120 2
kPaP 3.1472
8/13/2019 Ideal Gas Law PPT
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A balloon has a volume of 500 ml at a
temperature of 22oC and a pressure of 755
mmHg. If the balloon is cooled to 0o
C anda pressure of 145 mmHg, what is its new
volume?
ml
V3.2409
2
K
VmmHg
K
mlmmHg
273
145
295
500755 2
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Avogadros Principle
Under similar conditions (same Temp and
Pressure) equal volumes of gases contain
equal numbers of particles.
10 L of H2(g) and 10 L of O2(g)
Both at Standard Temperature and
Pressure (STP) contain
The same number of particles!
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Molar Volume
The volume of 1 mole of gas particlesat STP
is 22.4 L
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Ideal Gas Law Animation:
http://www.marymount.k12.ny.us/marynet/06stwbwrk/06gas/2lpimavogdro/2lpimavogadro.htmlhttp://www.marymount.k12.ny.us/marynet/06stwbwrk/06gas/2lpimavogdro/2lpimavogadro.html8/13/2019 Ideal Gas Law PPT
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Try this:
1 mole of gas occupies 22.4 L at STP
= __________ ml
(22400)= ___________ moles of gas
(1 mole)
= ___________ particles(6.02 x 1023)
8/13/2019 Ideal Gas Law PPT
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How many particles in 11.2 dm3of gas at STP?
0.5 moles = 3.01 x 1023particles
22,400 cm3 of NH3gas at STP weighs?
= 22.4 L = 1 mole = 17 grams (add up MW)44.8 L of NH3at STP weighs?
= 2 moles = 34 grams
_____ grams = 1 mole of nitrogen gas
= _____ L at STP?
mole
L
L
4.22
8.44
28.00
22.4
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How many N2molecules are
in 22.4 dm3 at STP?
= 1 mole = 6.02 x 1023
What volume will 1.2 x 1024H2 molecules
occupy at STP?
= 2 moles = 44.8 L at STP
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Ideal Gas Equation
Use when NOTat STP!!!
PV= nRTP = Pressure (in kPa)
V = Volume (in Liters or dm3)n = number of moles
T = Temperature (in Kelvin)
R =8.31 L kPa
mole K
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Development of R in
Kmole
LkPa
Kmole
LkPa
nT
PVR
31.82731
4.223.101
Kmole
LkPa
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1. What volume will 2 moles of NO2occupyat 300 Kelvin and 90 kPa?
LV
KmolesVkPa
nRTPV
4.5590
30031.82
30031.8290
8/13/2019 Ideal Gas Law PPT
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What will be the temp of 2 grams of
H2if 5000 cm3is at 5 atm?
KT
TmoleLkPa
nRTPV
8.30431.81
55.506
31.8155.506
8/13/2019 Ideal Gas Law PPT
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Finding Molecular Weight of a Gas
Remember: MW = grams / moles
Converting grams to moles
Divide grams by the molecular weight
8/13/2019 Ideal Gas Law PPT
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1) 5.0 L of a gas weighs 30.00 g at 20o C &
92 kPa. What is the mole weight of the gas?
g/mol581mol0.19
g30.00MW
PV=nRT
92kPa 5.0 L= n 8.31 293 K
n = 0.19 mol
mol?
g30.00
moles
gramsMW
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2)If the mole weight of a gas is 26 g/mol and
18.00 g of the gas is 30 L at 21oC, what is the
pressure of the gas?
PV= nRT
P x 30 L=0.69 mol x 8.31 x 294 K
P = 56.2kPa
mol0.69
g/mol26
g18.00
MW
gn
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Stoichiometry
Solving Steps.
Balance the Equation
Change grams to moles
Use mole ratio to solve
Change moles to volumes
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Use mole ratio
(coefficients)
Use 22.4 L/mol
@ STPOr PV = nRT
Use MWon P.T.
Use MWon P.T.
Use 22.4 L/mol
@ STPOr PV = nRT
8/13/2019 Ideal Gas Law PPT
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Mg (c) + HCl (ag)MgCl2+ H2(g)
If 2.43 g Mg react what volume of H2isproduced? (at STP)
Mg (c) + HCl (ag)MgCl2+ H2(g)
2.43 g Mg
0.1 mole
mol
gg
3.24
43.2
1:1
molesmol
L 1.04.22
0.1 moles
2
2.24 L H2
? L
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)313)(31.8)(1.0())(85( KmolVkPa
nRTPV
Mg (c) +2HCl (ag)MgCl2+ H2(g)
If 2.43 g Mg react what volume of H2is produced at
40oC and 85 kPa?
Mg (c) + HCl (ag)MgCl2+ H2(g)
2.43 g Mg
0.1 mole
mol
gg
3.24
43.2
1:10.1 moles
2
3.06 L H2? L
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If 250 ml of H2is produced at 20oC &
100 kPa, what mass of Mg reacted?
KnLkPa 29331.825.0100
2H01.0 molesn
Mg (c) + HCl (ag)MgCl2+ H2(g)2
? g 250 ml
nRTPV
0.01 moles0.01 mole1:1
0.243 g Mg
molesmol
g01.03.24
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Volume to Volume
THE MOLE RATIO IS THE SAME ASTHE VOLUME RATIO.
Liters BUse mole ratio
(coefficients)Liters A
B i f th
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Burning of methane:
What vol. of oxygen is needed to completely
burn 1 L of methane?
CH4+ O2 CO2(g) + H2O (l)
2.0 L1:2
1.0 L
2 2
B i f th
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Burning of methane:
To produce 11.2 L of CO2requires how
many moles of O2
at STP?
CH4+ O2 CO2(g) + H2O (l)
22.4 L 2:1 11.2 L1 mole =
2 2