SlideShare ist ein Scribd-Unternehmen logo
1 von 60
Downloaden Sie, um offline zu lesen
Gases
Chapter 5
Gases
Gases
Characteristics of Gases
• Unlike liquids and solids, they
 Expand to fill their containers.
 Are highly compressible.
 Have extremely low densities.
Gases
Measurements
• We have learned in our early chapters
and experienced in the lab, the means
of measurement for solids and liquids
• We will begin our study of gases by
looking at the means we employ to
make measurements on gases
Gases
Measurements involving
Gases
• To describe a gas we must specify the
following:
1.Volume
2. Amount
3.Temperature
4. Pressure
Gases
Volume of Gases
• Gases expand uniformly to fill any
container they are placed in
• Therefore, the volume of a gas is the
volume of its container
• Volumes are expressed in L, cm3
or m3
Gases
Amount
• The amount of matter in a sample of
gas is expressed in terms of the
number of moles(n)
• Sometimes the mas in grams is given
• n = g/mol mass(M)
• n(M)= g
Gases
Temperature
• Temperature of a gas is measured in
Celsius
• Calculations will require conversion to
the Kelvin scale
• TK = Tcelsius + 273.15
• Temperature is expressed to the
nearest degree (simply add 273 to
celsius temperature)
Gases
• Pressure is the
amount of force
applied to an area.
Pressure
• Atmospheric
pressure is the
weight of air per
unit of area.
P =
F
A
Gases
Units of Pressure
• English System pounds per square inch
(psi)
• Pascals (SI unit)
 1 Pa = 1 N/m2
• Bar
 1 bar = 105
Pa = 100 kPa
Gases
Units of Pressure
• mm Hg or torr
These units are literally
the difference in the
heights measured in mm
(h) of two connected
columns of mercury.
• Atmosphere
1.00 atm = 760 torr
Gases
Manometer
Used to measure the
difference in pressure
between atmospheric
pressure and that of a
gas in a vessel.
Gases
Standard Pressure
• Normal atmospheric pressure at sea
level.
• It is equal to
1.00 atm
760 torr (760 mm Hg)
101.325 kPa
Gases
Boyle’s Law
The volume of a fixed quantity of gas at
constant temperature is inversely proportional
to the pressure.
Gases
Boyle’s Law
Gases
As P and V are
inversely proportional
A plot of V versus P
results in a curve.
Since
V = k (1/P)
This means a plot of
V versus 1/P will be
a straight line.
PV = k
Gases
Charles’s Law
• The volume of a fixed
amount of gas at
constant pressure is
directly proportional to its
absolute temperature.
A plot of V versus T will be a straight line.
• i.e.,
V
T
= k
Gases
Avogadro’s Law
• The volume of a gas at constant temperature
and pressure is directly proportional to the
number of moles of the gas.
• Mathematically, this means V = kn
Gases
Ideal-Gas Equation
V ∝ 1/P (Boyle’s law)
V ∝ T (Charles’s law)
V ∝ n (Avogadro’s law)
• So far we’ve seen that
• Combining these, we get
V ∝
nT
P
Gases
Ideal-Gas Equation
The constant of
proportionality is
known as R, the
gas constant.
Gases
Ideal-Gas Equation
The relationship
then becomes
nT
P
V ∝
nT
P
V = R
or
PV = nRT
Gases
Ideal-Gas Equation
Gases
Densities of Gases
If we divide both sides of the ideal-gas
equation by V and by RT, we get
n
V
P
RT
=
Gases
• We know that
moles × molecular mass = mass
Densities of Gases
• So multiplying both sides by the
molecular mass (Μ ) gives
n × Μ = m
PΜ
RT
m
V
=
Gases
Densities of Gases
• Mass ÷ volume = density
• So,
• Note: One only needs to know the
molecular mass, the pressure, and the
temperature to calculate the density of
a gas.
PΜ
RT
m
V
=d =
Gases
Molecular Mass
We can manipulate the density
equation to enable us to find the
molecular mass of a gas:
Becomes
PΜ
RT
d =
dRT
P
Μ =
Gases
The conditions 0 0
C and 1 atm are called standard
temperature and pressure (STP).
PV = nRT
R =
PV
nT
=
(1 atm)(22.414L)
(1 mol)(273.15 K)
R = 0.082057 L • atm / (mol • K)
5.4
Experiments show that at STP, 1 mole of an ideal gas
occupies 22.414 L.
Gases
What is the volume (in liters) occupied by 49.8 g of HCl at
STP?
PV = nRT
V =
nRT
P
T = 0 0
C = 273.15 K
P = 1 atm
n = 49.8 g x
1 mol HCl
36.45 g HCl
= 1.37 mol
V =
1 atm
1.37 mol x 0.0821 x 273.15 KL•atm
mol•K
V = 30.6 L
5.4
Gases
Argon is an inert gas used in lightbulbs to retard the
vaporization of the filament. A certain lightbulb containing
argon at 1.20 atm and 18 0
C is heated to 85 0
C at constant
volume. What is the final pressure of argon in the lightbulb
(in atm)?
PV = nRT n, V and R are constant
nR
V
=
P
T
= constant
P1
T1
P2
T2
=
P1 = 1.20 atm
T1 = 291 K
P2 = ?
T2 = 358 K
P2 = P1 x
T2
T1
= 1.20 atm x 358 K
291 K
= 1.48 atm
5.4
Gases
Density (d) Calculations
d = m
V
=
PM
RT
m is the mass of the gas in g
M is the molar mass of the gas
Molar Mass (M ) of a Gaseous Substance
dRT
P
M = d is the density of the gas in g/L
5.4
Gases
A 2.10-L vessel contains 4.65 g of a gas at 1.00 atm and
27.0 0
C. What is the molar mass of the gas?
5.4
dRT
P
M = d = m
V
4.65 g
2.10 L
= = 2.21
g
L
M =
2.21
g
L
1 atm
x 0.0821 x 300.15 KL•atm
mol•K
M = 54.6 g/mol
Gases
Gas Stoichiometry
What is the volume of CO2 produced at 37 0
C and 1.00 atm
when 5.60 g of glucose are used up in the reaction:
C6H12O6 (s) + 6O2 (g) 6CO2 (g) + 6H2O (l)
g C6H12O6 mol C6H12O6 mol CO2 V CO2
5.60 g C6H12O6
1 mol C6H12O6
180 g C6H12O6
x
6 mol CO2
1 mol C6H12O6
x = 0.187 mol CO2
V =
nRT
P
0.187 mol x 0.0821 x 310.15 K
L•atm
mol•K
1.00 atm
= = 4.76 L
5.5
Gases
Dalton’s Law of
Partial Pressures
• The total pressure of a mixture of gases
equals the sum of the pressures that
each would exert if it were present
alone.
• In other words,
Ptotal = P1 + P2 + P3 + …
Gases
Dalton’s Law of Partial Pressures
V and T
are
constant
P1 P2 Ptotal = P1 + P2
5.6
Gases
Consider a case in which two gases, A and B, are in a container of
volume V.
PA =
nART
V
PB =
nBRT
V
nA is the number of moles of A
nB is the number of moles of B
PT = PA + PB XA =
nA
nA + nB
XB =
nB
nA + nB
PA = XA PT PB = XB PT
Pi = Xi PT
5.6
mole fraction (Xi) =
ni
nT
Gases
A sample of natural gas contains 8.24 moles of CH4, 0.421
moles of C2H6, and 0.116 moles of C3H8. If the total
pressure of the gases is 1.37 atm, what is the partial pressure
of propane (C3H8)?
Pi = Xi PT
Xpropane =
0.116
8.24 + 0.421 + 0.116
PT = 1.37 atm
= 0.0132
Ppropane = 0.0132 x 1.37 atm = 0.0181 atm
5.6
Gases
Partial Pressures
• When one collects a gas over water, there is
water vapor mixed in with the gas.
• To find only the pressure of the desired gas,
one must subtract the vapor pressure of
water from the total pressure.
Gases
2KClO3 (s) 2KCl (s) + 3O2 (g)
Bottle full of oxygen gas
and water vapor
PT = PO + PH O2 2 5.6
Gases
5.6
Gases
Chemistry in Action:
Scuba Diving and the Gas Laws
P V
Depth (ft) Pressure
(atm)
0 1
33 2
66 3
5.6
Gases
Kinetic-Molecular Theory
This is a model that
aids in our
understanding of what
happens to gas
particles as
environmental
conditions change.
Gases
Kinetic Molecular Theory of Gases
1. A gas is composed of molecules that are separated from each
other by distances far greater than their own dimensions. The
molecules can be considered to be points; that is, they possess
mass but have negligible volume.
2. Gas molecules are in constant motion in random directions, and
they frequently collide with one another. Collisions among
molecules are perfectly elastic.
3. Gas molecules exert neither attractive nor repulsive forces on one
another.
4. The average kinetic energy of the molecules is proportional to the
temperature of the gas in kelvins. Any two gases at the same
temperature will have the same average kinetic energy
5.7
KE = ½ mu2
Gases
Kinetic theory of gases and …
• Compressibility of Gases
• Boyle’s Law
P α collision rate with wall
Collision rate α number density
Number density α 1/V
P α 1/V
• Charles’ Law
P α collision rate with wall
Collision rate α average kinetic energy of gas molecules
Average kinetic energy α T
P α T
5.7
Gases
Kinetic theory of gases and …
• Avogadro’s Law
P α collision rate with wall
Collision rate α number density
Number density α n
P α n
• Dalton’s Law of Partial Pressures
Molecules do not attract or repel one another
P exerted by one type of molecule is unaffected by the
presence of another gas
Ptotal = ΣPi
5.7
Gases
Main Tenets of Kinetic-
Molecular Theory
The average kinetic
energy of the
molecules is
proportional to the
absolute
temperature.
Gases
Apparatus for studying molecular speed distribution
5.7
Gases
The distribution of speeds
for nitrogen gas molecules
at three different temperatures
The distribution of speeds
of three different gases
at the same temperature
5.7
urms = 3RT
M√
Gases
Diffusion
The spread of one
substance
throughout a space
or throughout a
second substance.
Gases
Gas diffusion is the gradual mixing of molecules of one gas with
molecules of another by virtue of their kinetic properties.
5.7
NH3
17 g/mol
HCl
36 g/mol
NH4Cl
r1
r2
M2
M1√=
Gases
Effusion
The escape of
gas molecules
through a tiny
hole into an
evacuated
space.
Gases
Gas effusion is the is the process by which gas under pressure
escapes from one compartment of a container to another by passing
through a small opening.
5.7
r1
r2
t2
t1
M2
M1√= =
Nickel forms a gaseous compound of the formula Ni(CO)x
What is the value of x given that under the same conditions
methane (CH4) effuses 3.3 times faster than the compound?
r1 = 3.3 x r2
M1 = 16 g/mol
M2 =
r1
r2
( )
2
x M1 = (3.3)2
x 16 = 174.2
58.7 + x • 28 = 174.2 x = 4.1 ~ 4
Gases
Gases
Gases
Real Gases
In the real world, the
behavior of gases
only conforms to the
ideal-gas equation
at relatively high
temperature and low
pressure.
Gases
Deviations from Ideal Behavior
The assumptions made in the kinetic-molecular
model break down at high pressure and/or low
temperature.
Gases
Deviations from Ideal Behavior
1 mole of ideal gas
PV = nRT
n =
PV
RT
= 1.0
5.8
Repulsive Forces
Attractive Forces
Gases
Effect of intermolecular forces on the pressure exerted by a gas.
5.8
Gases
Corrections for Nonideal
Behavior
• The ideal-gas equation can be adjusted
to take these deviations from ideal
behavior into account.
• The corrected ideal-gas equation is
known as the van der Waals equation.
Gases
5.8
Van der Waals equation
nonideal gas
P + (V – nb) = nRTan2
V2( )
}
corrected
pressure
}
corrected
volume
Gases
Gases

Más contenido relacionado

Was ist angesagt?

Ch5 z5e gases
Ch5 z5e gasesCh5 z5e gases
Ch5 z5e gasesblachman
 
AP Chemistry Chapter 10 Outline
AP Chemistry Chapter 10 OutlineAP Chemistry Chapter 10 Outline
AP Chemistry Chapter 10 OutlineJane Hamze
 
Chemistry notes ideal gas laws
Chemistry notes ideal gas lawsChemistry notes ideal gas laws
Chemistry notes ideal gas lawshega coc
 
Ch 14 Ideal Gas Law & Kinetic Theory
Ch 14 Ideal Gas Law & Kinetic TheoryCh 14 Ideal Gas Law & Kinetic Theory
Ch 14 Ideal Gas Law & Kinetic TheoryScott Thomas
 
Analytical chemistry ch01 chemical measurements
Analytical chemistry ch01 chemical measurementsAnalytical chemistry ch01 chemical measurements
Analytical chemistry ch01 chemical measurementsSa'ib J. Khouri
 
Chapter 5 gases
Chapter 5 gasesChapter 5 gases
Chapter 5 gasesJeff Auty
 
Ideal gas law practice mccpot
Ideal gas law practice mccpotIdeal gas law practice mccpot
Ideal gas law practice mccpotsohbel
 
New chm 151_unit_11_power_points_su13
New chm 151_unit_11_power_points_su13New chm 151_unit_11_power_points_su13
New chm 151_unit_11_power_points_su13caneman1
 
Chapter 10 Lecture- Gases
Chapter 10 Lecture- GasesChapter 10 Lecture- Gases
Chapter 10 Lecture- GasesMary Beth Smith
 
Ch.06 Chemical Equilibrium
Ch.06 Chemical EquilibriumCh.06 Chemical Equilibrium
Ch.06 Chemical EquilibriumSa'ib J. Khouri
 
Thermodynamics objective
Thermodynamics objectiveThermodynamics objective
Thermodynamics objectivesuresh gdvm
 
New chm 151_unit_9_power_points
New chm 151_unit_9_power_pointsNew chm 151_unit_9_power_points
New chm 151_unit_9_power_pointscaneman1
 
Assignment gaseous state_jh_sir-2621
Assignment gaseous state_jh_sir-2621Assignment gaseous state_jh_sir-2621
Assignment gaseous state_jh_sir-2621NEETRICKSJEE
 
Chemical Thermodynamics
Chemical Thermodynamics Chemical Thermodynamics
Chemical Thermodynamics suresh gdvm
 

Was ist angesagt? (18)

Ch5 z5e gases
Ch5 z5e gasesCh5 z5e gases
Ch5 z5e gases
 
AP Chemistry Chapter 10 Outline
AP Chemistry Chapter 10 OutlineAP Chemistry Chapter 10 Outline
AP Chemistry Chapter 10 Outline
 
Chemistry notes ideal gas laws
Chemistry notes ideal gas lawsChemistry notes ideal gas laws
Chemistry notes ideal gas laws
 
Ch 14 Ideal Gas Law & Kinetic Theory
Ch 14 Ideal Gas Law & Kinetic TheoryCh 14 Ideal Gas Law & Kinetic Theory
Ch 14 Ideal Gas Law & Kinetic Theory
 
Analytical chemistry ch01 chemical measurements
Analytical chemistry ch01 chemical measurementsAnalytical chemistry ch01 chemical measurements
Analytical chemistry ch01 chemical measurements
 
Ch5 Gases
Ch5 GasesCh5 Gases
Ch5 Gases
 
Adv chem chapt 5
Adv chem chapt 5Adv chem chapt 5
Adv chem chapt 5
 
Chapter 5 gases
Chapter 5 gasesChapter 5 gases
Chapter 5 gases
 
Gas Laws
Gas LawsGas Laws
Gas Laws
 
Ideal gas law practice mccpot
Ideal gas law practice mccpotIdeal gas law practice mccpot
Ideal gas law practice mccpot
 
New chm 151_unit_11_power_points_su13
New chm 151_unit_11_power_points_su13New chm 151_unit_11_power_points_su13
New chm 151_unit_11_power_points_su13
 
Chapter 10 Lecture- Gases
Chapter 10 Lecture- GasesChapter 10 Lecture- Gases
Chapter 10 Lecture- Gases
 
Ch.06 Chemical Equilibrium
Ch.06 Chemical EquilibriumCh.06 Chemical Equilibrium
Ch.06 Chemical Equilibrium
 
Thermodynamics objective
Thermodynamics objectiveThermodynamics objective
Thermodynamics objective
 
New chm 151_unit_9_power_points
New chm 151_unit_9_power_pointsNew chm 151_unit_9_power_points
New chm 151_unit_9_power_points
 
Chapter10.pdf
Chapter10.pdfChapter10.pdf
Chapter10.pdf
 
Assignment gaseous state_jh_sir-2621
Assignment gaseous state_jh_sir-2621Assignment gaseous state_jh_sir-2621
Assignment gaseous state_jh_sir-2621
 
Chemical Thermodynamics
Chemical Thermodynamics Chemical Thermodynamics
Chemical Thermodynamics
 

Ähnlich wie Chem 101 week 12 ch 5

Chapter 5 gases reduced1
Chapter 5  gases reduced1Chapter 5  gases reduced1
Chapter 5 gases reduced1mtsaeed03
 
Wk 6 p3 wk 7-p8_1.2-1.3 & 10.1-10.3_ideal gases
Wk 6 p3 wk 7-p8_1.2-1.3 & 10.1-10.3_ideal gasesWk 6 p3 wk 7-p8_1.2-1.3 & 10.1-10.3_ideal gases
Wk 6 p3 wk 7-p8_1.2-1.3 & 10.1-10.3_ideal gaseschris lembalemba
 
Gases theory and basics .. general chemistry
Gases theory and basics .. general chemistryGases theory and basics .. general chemistry
Gases theory and basics .. general chemistryfuat8
 
Gen. Chem 1 - gas laws.pptx
Gen. Chem 1 - gas laws.pptxGen. Chem 1 - gas laws.pptx
Gen. Chem 1 - gas laws.pptxHermyFeliciano
 
12 Gas Laws
12 Gas Laws12 Gas Laws
12 Gas Lawsjanetra
 
States of matter
States of matterStates of matter
States of matterHoshi94
 
Ch. 10 Gases
Ch. 10 GasesCh. 10 Gases
Ch. 10 Gasesewalenta
 
Chapter 14 Gas Laws ppt 2017 good (1).ppt
Chapter 14 Gas Laws ppt 2017 good (1).pptChapter 14 Gas Laws ppt 2017 good (1).ppt
Chapter 14 Gas Laws ppt 2017 good (1).pptmikeebio1
 
Unit 4: Behavior of Gases
Unit 4: Behavior of GasesUnit 4: Behavior of Gases
Unit 4: Behavior of GasesJimnaira Abanto
 

Ähnlich wie Chem 101 week 12 ch 5 (20)

Gas Law
Gas LawGas Law
Gas Law
 
Chapter_5_Gases.ppt
Chapter_5_Gases.pptChapter_5_Gases.ppt
Chapter_5_Gases.ppt
 
Chapter 5 gases reduced1
Chapter 5  gases reduced1Chapter 5  gases reduced1
Chapter 5 gases reduced1
 
Wk 6 p3 wk 7-p8_1.2-1.3 & 10.1-10.3_ideal gases
Wk 6 p3 wk 7-p8_1.2-1.3 & 10.1-10.3_ideal gasesWk 6 p3 wk 7-p8_1.2-1.3 & 10.1-10.3_ideal gases
Wk 6 p3 wk 7-p8_1.2-1.3 & 10.1-10.3_ideal gases
 
ch5.pptx
ch5.pptxch5.pptx
ch5.pptx
 
Gas
GasGas
Gas
 
Gases theory and basics .. general chemistry
Gases theory and basics .. general chemistryGases theory and basics .. general chemistry
Gases theory and basics .. general chemistry
 
Gen. Chem 1 - gas laws.pptx
Gen. Chem 1 - gas laws.pptxGen. Chem 1 - gas laws.pptx
Gen. Chem 1 - gas laws.pptx
 
12 Gas Laws
12 Gas Laws12 Gas Laws
12 Gas Laws
 
State Of Matter
State Of MatterState Of Matter
State Of Matter
 
States of matter
States of matterStates of matter
States of matter
 
Gases.pptx
Gases.pptxGases.pptx
Gases.pptx
 
Ch. 10 Gases
Ch. 10 GasesCh. 10 Gases
Ch. 10 Gases
 
Chapter 14 Gas Laws ppt 2017 good (1).ppt
Chapter 14 Gas Laws ppt 2017 good (1).pptChapter 14 Gas Laws ppt 2017 good (1).ppt
Chapter 14 Gas Laws ppt 2017 good (1).ppt
 
Chapter 5 notes
Chapter 5 notesChapter 5 notes
Chapter 5 notes
 
the gaseous state of matter
the gaseous state of matterthe gaseous state of matter
the gaseous state of matter
 
Gas Laws
Gas LawsGas Laws
Gas Laws
 
Physical chemi gases
Physical chemi gasesPhysical chemi gases
Physical chemi gases
 
Unit 4: Behavior of Gases
Unit 4: Behavior of GasesUnit 4: Behavior of Gases
Unit 4: Behavior of Gases
 
12.3
12.312.3
12.3
 

Mehr von tdean1

Chem 101 week 13 ch11
Chem 101 week 13 ch11Chem 101 week 13 ch11
Chem 101 week 13 ch11tdean1
 
Chem 101 week 11 ch10
Chem 101 week 11 ch10Chem 101 week 11 ch10
Chem 101 week 11 ch10tdean1
 
Chem 101 week 10 ch9
Chem 101 week 10 ch9Chem 101 week 10 ch9
Chem 101 week 10 ch9tdean1
 
Chem 101 week 9 ch8
Chem 101 week 9 ch8Chem 101 week 9 ch8
Chem 101 week 9 ch8tdean1
 
Chem 101 week 8 ch7
Chem 101 week 8 ch7Chem 101 week 8 ch7
Chem 101 week 8 ch7tdean1
 
Chem 101 week 7 pt1
Chem 101 week 7 pt1Chem 101 week 7 pt1
Chem 101 week 7 pt1tdean1
 
Chem 101 week 6 pt2
Chem 101 week 6 pt2Chem 101 week 6 pt2
Chem 101 week 6 pt2tdean1
 
Chem 101 week 6 pt1
Chem 101 week 6 pt1Chem 101 week 6 pt1
Chem 101 week 6 pt1tdean1
 
Chem 101 week 5
Chem 101 week 5Chem 101 week 5
Chem 101 week 5tdean1
 
Chem 101 week 4
Chem 101 week 4Chem 101 week 4
Chem 101 week 4tdean1
 
Chem 101 week 3
Chem 101 week 3Chem 101 week 3
Chem 101 week 3tdean1
 
Chem 101 week 2
Chem 101 week 2Chem 101 week 2
Chem 101 week 2tdean1
 
Chem 101 week 1
Chem 101 week 1Chem 101 week 1
Chem 101 week 1tdean1
 

Mehr von tdean1 (13)

Chem 101 week 13 ch11
Chem 101 week 13 ch11Chem 101 week 13 ch11
Chem 101 week 13 ch11
 
Chem 101 week 11 ch10
Chem 101 week 11 ch10Chem 101 week 11 ch10
Chem 101 week 11 ch10
 
Chem 101 week 10 ch9
Chem 101 week 10 ch9Chem 101 week 10 ch9
Chem 101 week 10 ch9
 
Chem 101 week 9 ch8
Chem 101 week 9 ch8Chem 101 week 9 ch8
Chem 101 week 9 ch8
 
Chem 101 week 8 ch7
Chem 101 week 8 ch7Chem 101 week 8 ch7
Chem 101 week 8 ch7
 
Chem 101 week 7 pt1
Chem 101 week 7 pt1Chem 101 week 7 pt1
Chem 101 week 7 pt1
 
Chem 101 week 6 pt2
Chem 101 week 6 pt2Chem 101 week 6 pt2
Chem 101 week 6 pt2
 
Chem 101 week 6 pt1
Chem 101 week 6 pt1Chem 101 week 6 pt1
Chem 101 week 6 pt1
 
Chem 101 week 5
Chem 101 week 5Chem 101 week 5
Chem 101 week 5
 
Chem 101 week 4
Chem 101 week 4Chem 101 week 4
Chem 101 week 4
 
Chem 101 week 3
Chem 101 week 3Chem 101 week 3
Chem 101 week 3
 
Chem 101 week 2
Chem 101 week 2Chem 101 week 2
Chem 101 week 2
 
Chem 101 week 1
Chem 101 week 1Chem 101 week 1
Chem 101 week 1
 

Último

EPC Contractors aspects Presentation.pdf
EPC Contractors  aspects Presentation.pdfEPC Contractors  aspects Presentation.pdf
EPC Contractors aspects Presentation.pdfGiuseppe Tommasone
 
0311 National Accounts Online Giving Trends.pdf
0311 National Accounts Online Giving Trends.pdf0311 National Accounts Online Giving Trends.pdf
0311 National Accounts Online Giving Trends.pdfBloomerang
 
L-1 VISA Business (Plan Sample) - Plan Writers
L-1 VISA Business (Plan Sample) - Plan WritersL-1 VISA Business (Plan Sample) - Plan Writers
L-1 VISA Business (Plan Sample) - Plan WritersPlan Writers
 
HOW TO START EARNING WITH AFFILIATE MARKETING
HOW TO START EARNING WITH AFFILIATE MARKETINGHOW TO START EARNING WITH AFFILIATE MARKETING
HOW TO START EARNING WITH AFFILIATE MARKETINGNATHAN SPEAKS
 
Streamlining Your Accounting A Guide to QuickBooks Migration Tools.pptx
Streamlining Your Accounting A Guide to QuickBooks Migration Tools.pptxStreamlining Your Accounting A Guide to QuickBooks Migration Tools.pptx
Streamlining Your Accounting A Guide to QuickBooks Migration Tools.pptxPaulBryant58
 
14 march 2024-capital-markets-update eni.pdf
14 march 2024-capital-markets-update eni.pdf14 march 2024-capital-markets-update eni.pdf
14 march 2024-capital-markets-update eni.pdfEni
 
A Comprehensive Case Study on the IL&FS Crisis (final).pptx
A Comprehensive Case Study on the IL&FS Crisis (final).pptxA Comprehensive Case Study on the IL&FS Crisis (final).pptx
A Comprehensive Case Study on the IL&FS Crisis (final).pptxShainaMaheshwari1
 
Mist Cooling & Fogging System Company in Egypt
Mist Cooling & Fogging System Company in EgyptMist Cooling & Fogging System Company in Egypt
Mist Cooling & Fogging System Company in Egyptopstechsanjanasingh
 
10 Tips for Great Teams CSUN Conference 2024
10 Tips for Great Teams CSUN Conference 202410 Tips for Great Teams CSUN Conference 2024
10 Tips for Great Teams CSUN Conference 2024Nate Evans
 
CXO 2.0 Conference (Event Information Deck | Dec'24-Mar'25)
CXO 2.0 Conference (Event Information Deck | Dec'24-Mar'25)CXO 2.0 Conference (Event Information Deck | Dec'24-Mar'25)
CXO 2.0 Conference (Event Information Deck | Dec'24-Mar'25)CXO 2.0 Conference
 
PHX Corporate Presentation March 2024 Final
PHX Corporate Presentation March 2024 FinalPHX Corporate Presentation March 2024 Final
PHX Corporate Presentation March 2024 FinalPanhandleOilandGas
 
Mist Cooling & Fogging System Company in Saudi Arabia
Mist Cooling & Fogging System Company in Saudi ArabiaMist Cooling & Fogging System Company in Saudi Arabia
Mist Cooling & Fogging System Company in Saudi Arabiaopstechsanjanasingh
 
Unleashing the Power of Fandom: A Short Guide to Fan Business
Unleashing the Power of Fandom: A Short Guide to Fan BusinessUnleashing the Power of Fandom: A Short Guide to Fan Business
Unleashing the Power of Fandom: A Short Guide to Fan Businesstompeter3736
 
The 10 Most Influential Women Making Difference In 2024.pdf
The 10 Most Influential Women Making Difference In 2024.pdfThe 10 Most Influential Women Making Difference In 2024.pdf
The 10 Most Influential Women Making Difference In 2024.pdfInsightsSuccess4
 
A Case Study On SQUARE GROUP Bangladesh.pdf
A Case Study On SQUARE GROUP Bangladesh.pdfA Case Study On SQUARE GROUP Bangladesh.pdf
A Case Study On SQUARE GROUP Bangladesh.pdfmeftaul987
 
Bus Eth ch3 ppt.ppt business ethics and corporate social responsibilities ppt
Bus Eth ch3 ppt.ppt business ethics and corporate social responsibilities pptBus Eth ch3 ppt.ppt business ethics and corporate social responsibilities ppt
Bus Eth ch3 ppt.ppt business ethics and corporate social responsibilities pptendeworku
 
ICv2 Hobby Games White Paper 2024 - State of the Industry
ICv2 Hobby Games White Paper 2024 - State of the IndustryICv2 Hobby Games White Paper 2024 - State of the Industry
ICv2 Hobby Games White Paper 2024 - State of the IndustryDennisViau
 
Reframing Requirements: A Strategic Approach to Requirement Definition, with ...
Reframing Requirements: A Strategic Approach to Requirement Definition, with ...Reframing Requirements: A Strategic Approach to Requirement Definition, with ...
Reframing Requirements: A Strategic Approach to Requirement Definition, with ...Jake Truemper
 
"InShorts: A Game-Changer in the Digital News Age"
"InShorts: A Game-Changer in the Digital News Age""InShorts: A Game-Changer in the Digital News Age"
"InShorts: A Game-Changer in the Digital News Age"Adharsh45
 

Último (20)

EPC Contractors aspects Presentation.pdf
EPC Contractors  aspects Presentation.pdfEPC Contractors  aspects Presentation.pdf
EPC Contractors aspects Presentation.pdf
 
0311 National Accounts Online Giving Trends.pdf
0311 National Accounts Online Giving Trends.pdf0311 National Accounts Online Giving Trends.pdf
0311 National Accounts Online Giving Trends.pdf
 
L-1 VISA Business (Plan Sample) - Plan Writers
L-1 VISA Business (Plan Sample) - Plan WritersL-1 VISA Business (Plan Sample) - Plan Writers
L-1 VISA Business (Plan Sample) - Plan Writers
 
HOW TO START EARNING WITH AFFILIATE MARKETING
HOW TO START EARNING WITH AFFILIATE MARKETINGHOW TO START EARNING WITH AFFILIATE MARKETING
HOW TO START EARNING WITH AFFILIATE MARKETING
 
Streamlining Your Accounting A Guide to QuickBooks Migration Tools.pptx
Streamlining Your Accounting A Guide to QuickBooks Migration Tools.pptxStreamlining Your Accounting A Guide to QuickBooks Migration Tools.pptx
Streamlining Your Accounting A Guide to QuickBooks Migration Tools.pptx
 
14 march 2024-capital-markets-update eni.pdf
14 march 2024-capital-markets-update eni.pdf14 march 2024-capital-markets-update eni.pdf
14 march 2024-capital-markets-update eni.pdf
 
A Comprehensive Case Study on the IL&FS Crisis (final).pptx
A Comprehensive Case Study on the IL&FS Crisis (final).pptxA Comprehensive Case Study on the IL&FS Crisis (final).pptx
A Comprehensive Case Study on the IL&FS Crisis (final).pptx
 
Mist Cooling & Fogging System Company in Egypt
Mist Cooling & Fogging System Company in EgyptMist Cooling & Fogging System Company in Egypt
Mist Cooling & Fogging System Company in Egypt
 
10 Tips for Great Teams CSUN Conference 2024
10 Tips for Great Teams CSUN Conference 202410 Tips for Great Teams CSUN Conference 2024
10 Tips for Great Teams CSUN Conference 2024
 
CXO 2.0 Conference (Event Information Deck | Dec'24-Mar'25)
CXO 2.0 Conference (Event Information Deck | Dec'24-Mar'25)CXO 2.0 Conference (Event Information Deck | Dec'24-Mar'25)
CXO 2.0 Conference (Event Information Deck | Dec'24-Mar'25)
 
PHX Corporate Presentation March 2024 Final
PHX Corporate Presentation March 2024 FinalPHX Corporate Presentation March 2024 Final
PHX Corporate Presentation March 2024 Final
 
Mist Cooling & Fogging System Company in Saudi Arabia
Mist Cooling & Fogging System Company in Saudi ArabiaMist Cooling & Fogging System Company in Saudi Arabia
Mist Cooling & Fogging System Company in Saudi Arabia
 
Unleashing the Power of Fandom: A Short Guide to Fan Business
Unleashing the Power of Fandom: A Short Guide to Fan BusinessUnleashing the Power of Fandom: A Short Guide to Fan Business
Unleashing the Power of Fandom: A Short Guide to Fan Business
 
The 10 Most Influential Women Making Difference In 2024.pdf
The 10 Most Influential Women Making Difference In 2024.pdfThe 10 Most Influential Women Making Difference In 2024.pdf
The 10 Most Influential Women Making Difference In 2024.pdf
 
A Case Study On SQUARE GROUP Bangladesh.pdf
A Case Study On SQUARE GROUP Bangladesh.pdfA Case Study On SQUARE GROUP Bangladesh.pdf
A Case Study On SQUARE GROUP Bangladesh.pdf
 
Bus Eth ch3 ppt.ppt business ethics and corporate social responsibilities ppt
Bus Eth ch3 ppt.ppt business ethics and corporate social responsibilities pptBus Eth ch3 ppt.ppt business ethics and corporate social responsibilities ppt
Bus Eth ch3 ppt.ppt business ethics and corporate social responsibilities ppt
 
WAM Corporate Presentation Mar 12 2024_Video.pdf
WAM Corporate Presentation Mar 12 2024_Video.pdfWAM Corporate Presentation Mar 12 2024_Video.pdf
WAM Corporate Presentation Mar 12 2024_Video.pdf
 
ICv2 Hobby Games White Paper 2024 - State of the Industry
ICv2 Hobby Games White Paper 2024 - State of the IndustryICv2 Hobby Games White Paper 2024 - State of the Industry
ICv2 Hobby Games White Paper 2024 - State of the Industry
 
Reframing Requirements: A Strategic Approach to Requirement Definition, with ...
Reframing Requirements: A Strategic Approach to Requirement Definition, with ...Reframing Requirements: A Strategic Approach to Requirement Definition, with ...
Reframing Requirements: A Strategic Approach to Requirement Definition, with ...
 
"InShorts: A Game-Changer in the Digital News Age"
"InShorts: A Game-Changer in the Digital News Age""InShorts: A Game-Changer in the Digital News Age"
"InShorts: A Game-Changer in the Digital News Age"
 

Chem 101 week 12 ch 5

  • 2. Gases Characteristics of Gases • Unlike liquids and solids, they  Expand to fill their containers.  Are highly compressible.  Have extremely low densities.
  • 3. Gases Measurements • We have learned in our early chapters and experienced in the lab, the means of measurement for solids and liquids • We will begin our study of gases by looking at the means we employ to make measurements on gases
  • 4. Gases Measurements involving Gases • To describe a gas we must specify the following: 1.Volume 2. Amount 3.Temperature 4. Pressure
  • 5. Gases Volume of Gases • Gases expand uniformly to fill any container they are placed in • Therefore, the volume of a gas is the volume of its container • Volumes are expressed in L, cm3 or m3
  • 6. Gases Amount • The amount of matter in a sample of gas is expressed in terms of the number of moles(n) • Sometimes the mas in grams is given • n = g/mol mass(M) • n(M)= g
  • 7. Gases Temperature • Temperature of a gas is measured in Celsius • Calculations will require conversion to the Kelvin scale • TK = Tcelsius + 273.15 • Temperature is expressed to the nearest degree (simply add 273 to celsius temperature)
  • 8. Gases • Pressure is the amount of force applied to an area. Pressure • Atmospheric pressure is the weight of air per unit of area. P = F A
  • 9. Gases Units of Pressure • English System pounds per square inch (psi) • Pascals (SI unit)  1 Pa = 1 N/m2 • Bar  1 bar = 105 Pa = 100 kPa
  • 10. Gases Units of Pressure • mm Hg or torr These units are literally the difference in the heights measured in mm (h) of two connected columns of mercury. • Atmosphere 1.00 atm = 760 torr
  • 11. Gases Manometer Used to measure the difference in pressure between atmospheric pressure and that of a gas in a vessel.
  • 12. Gases Standard Pressure • Normal atmospheric pressure at sea level. • It is equal to 1.00 atm 760 torr (760 mm Hg) 101.325 kPa
  • 13. Gases Boyle’s Law The volume of a fixed quantity of gas at constant temperature is inversely proportional to the pressure.
  • 15. Gases As P and V are inversely proportional A plot of V versus P results in a curve. Since V = k (1/P) This means a plot of V versus 1/P will be a straight line. PV = k
  • 16. Gases Charles’s Law • The volume of a fixed amount of gas at constant pressure is directly proportional to its absolute temperature. A plot of V versus T will be a straight line. • i.e., V T = k
  • 17. Gases Avogadro’s Law • The volume of a gas at constant temperature and pressure is directly proportional to the number of moles of the gas. • Mathematically, this means V = kn
  • 18. Gases Ideal-Gas Equation V ∝ 1/P (Boyle’s law) V ∝ T (Charles’s law) V ∝ n (Avogadro’s law) • So far we’ve seen that • Combining these, we get V ∝ nT P
  • 19. Gases Ideal-Gas Equation The constant of proportionality is known as R, the gas constant.
  • 20. Gases Ideal-Gas Equation The relationship then becomes nT P V ∝ nT P V = R or PV = nRT
  • 22. Gases Densities of Gases If we divide both sides of the ideal-gas equation by V and by RT, we get n V P RT =
  • 23. Gases • We know that moles × molecular mass = mass Densities of Gases • So multiplying both sides by the molecular mass (Μ ) gives n × Μ = m PΜ RT m V =
  • 24. Gases Densities of Gases • Mass ÷ volume = density • So, • Note: One only needs to know the molecular mass, the pressure, and the temperature to calculate the density of a gas. PΜ RT m V =d =
  • 25. Gases Molecular Mass We can manipulate the density equation to enable us to find the molecular mass of a gas: Becomes PΜ RT d = dRT P Μ =
  • 26. Gases The conditions 0 0 C and 1 atm are called standard temperature and pressure (STP). PV = nRT R = PV nT = (1 atm)(22.414L) (1 mol)(273.15 K) R = 0.082057 L • atm / (mol • K) 5.4 Experiments show that at STP, 1 mole of an ideal gas occupies 22.414 L.
  • 27. Gases What is the volume (in liters) occupied by 49.8 g of HCl at STP? PV = nRT V = nRT P T = 0 0 C = 273.15 K P = 1 atm n = 49.8 g x 1 mol HCl 36.45 g HCl = 1.37 mol V = 1 atm 1.37 mol x 0.0821 x 273.15 KL•atm mol•K V = 30.6 L 5.4
  • 28. Gases Argon is an inert gas used in lightbulbs to retard the vaporization of the filament. A certain lightbulb containing argon at 1.20 atm and 18 0 C is heated to 85 0 C at constant volume. What is the final pressure of argon in the lightbulb (in atm)? PV = nRT n, V and R are constant nR V = P T = constant P1 T1 P2 T2 = P1 = 1.20 atm T1 = 291 K P2 = ? T2 = 358 K P2 = P1 x T2 T1 = 1.20 atm x 358 K 291 K = 1.48 atm 5.4
  • 29. Gases Density (d) Calculations d = m V = PM RT m is the mass of the gas in g M is the molar mass of the gas Molar Mass (M ) of a Gaseous Substance dRT P M = d is the density of the gas in g/L 5.4
  • 30. Gases A 2.10-L vessel contains 4.65 g of a gas at 1.00 atm and 27.0 0 C. What is the molar mass of the gas? 5.4 dRT P M = d = m V 4.65 g 2.10 L = = 2.21 g L M = 2.21 g L 1 atm x 0.0821 x 300.15 KL•atm mol•K M = 54.6 g/mol
  • 31. Gases Gas Stoichiometry What is the volume of CO2 produced at 37 0 C and 1.00 atm when 5.60 g of glucose are used up in the reaction: C6H12O6 (s) + 6O2 (g) 6CO2 (g) + 6H2O (l) g C6H12O6 mol C6H12O6 mol CO2 V CO2 5.60 g C6H12O6 1 mol C6H12O6 180 g C6H12O6 x 6 mol CO2 1 mol C6H12O6 x = 0.187 mol CO2 V = nRT P 0.187 mol x 0.0821 x 310.15 K L•atm mol•K 1.00 atm = = 4.76 L 5.5
  • 32. Gases Dalton’s Law of Partial Pressures • The total pressure of a mixture of gases equals the sum of the pressures that each would exert if it were present alone. • In other words, Ptotal = P1 + P2 + P3 + …
  • 33. Gases Dalton’s Law of Partial Pressures V and T are constant P1 P2 Ptotal = P1 + P2 5.6
  • 34. Gases Consider a case in which two gases, A and B, are in a container of volume V. PA = nART V PB = nBRT V nA is the number of moles of A nB is the number of moles of B PT = PA + PB XA = nA nA + nB XB = nB nA + nB PA = XA PT PB = XB PT Pi = Xi PT 5.6 mole fraction (Xi) = ni nT
  • 35. Gases A sample of natural gas contains 8.24 moles of CH4, 0.421 moles of C2H6, and 0.116 moles of C3H8. If the total pressure of the gases is 1.37 atm, what is the partial pressure of propane (C3H8)? Pi = Xi PT Xpropane = 0.116 8.24 + 0.421 + 0.116 PT = 1.37 atm = 0.0132 Ppropane = 0.0132 x 1.37 atm = 0.0181 atm 5.6
  • 36. Gases Partial Pressures • When one collects a gas over water, there is water vapor mixed in with the gas. • To find only the pressure of the desired gas, one must subtract the vapor pressure of water from the total pressure.
  • 37. Gases 2KClO3 (s) 2KCl (s) + 3O2 (g) Bottle full of oxygen gas and water vapor PT = PO + PH O2 2 5.6
  • 39. Gases Chemistry in Action: Scuba Diving and the Gas Laws P V Depth (ft) Pressure (atm) 0 1 33 2 66 3 5.6
  • 40. Gases Kinetic-Molecular Theory This is a model that aids in our understanding of what happens to gas particles as environmental conditions change.
  • 41. Gases Kinetic Molecular Theory of Gases 1. A gas is composed of molecules that are separated from each other by distances far greater than their own dimensions. The molecules can be considered to be points; that is, they possess mass but have negligible volume. 2. Gas molecules are in constant motion in random directions, and they frequently collide with one another. Collisions among molecules are perfectly elastic. 3. Gas molecules exert neither attractive nor repulsive forces on one another. 4. The average kinetic energy of the molecules is proportional to the temperature of the gas in kelvins. Any two gases at the same temperature will have the same average kinetic energy 5.7 KE = ½ mu2
  • 42. Gases Kinetic theory of gases and … • Compressibility of Gases • Boyle’s Law P α collision rate with wall Collision rate α number density Number density α 1/V P α 1/V • Charles’ Law P α collision rate with wall Collision rate α average kinetic energy of gas molecules Average kinetic energy α T P α T 5.7
  • 43. Gases Kinetic theory of gases and … • Avogadro’s Law P α collision rate with wall Collision rate α number density Number density α n P α n • Dalton’s Law of Partial Pressures Molecules do not attract or repel one another P exerted by one type of molecule is unaffected by the presence of another gas Ptotal = ΣPi 5.7
  • 44. Gases Main Tenets of Kinetic- Molecular Theory The average kinetic energy of the molecules is proportional to the absolute temperature.
  • 45. Gases Apparatus for studying molecular speed distribution 5.7
  • 46. Gases The distribution of speeds for nitrogen gas molecules at three different temperatures The distribution of speeds of three different gases at the same temperature 5.7 urms = 3RT M√
  • 47. Gases Diffusion The spread of one substance throughout a space or throughout a second substance.
  • 48. Gases Gas diffusion is the gradual mixing of molecules of one gas with molecules of another by virtue of their kinetic properties. 5.7 NH3 17 g/mol HCl 36 g/mol NH4Cl r1 r2 M2 M1√=
  • 49. Gases Effusion The escape of gas molecules through a tiny hole into an evacuated space.
  • 50. Gases Gas effusion is the is the process by which gas under pressure escapes from one compartment of a container to another by passing through a small opening. 5.7 r1 r2 t2 t1 M2 M1√= = Nickel forms a gaseous compound of the formula Ni(CO)x What is the value of x given that under the same conditions methane (CH4) effuses 3.3 times faster than the compound? r1 = 3.3 x r2 M1 = 16 g/mol M2 = r1 r2 ( ) 2 x M1 = (3.3)2 x 16 = 174.2 58.7 + x • 28 = 174.2 x = 4.1 ~ 4
  • 51. Gases
  • 52. Gases
  • 53. Gases Real Gases In the real world, the behavior of gases only conforms to the ideal-gas equation at relatively high temperature and low pressure.
  • 54. Gases Deviations from Ideal Behavior The assumptions made in the kinetic-molecular model break down at high pressure and/or low temperature.
  • 55. Gases Deviations from Ideal Behavior 1 mole of ideal gas PV = nRT n = PV RT = 1.0 5.8 Repulsive Forces Attractive Forces
  • 56. Gases Effect of intermolecular forces on the pressure exerted by a gas. 5.8
  • 57. Gases Corrections for Nonideal Behavior • The ideal-gas equation can be adjusted to take these deviations from ideal behavior into account. • The corrected ideal-gas equation is known as the van der Waals equation.
  • 58. Gases 5.8 Van der Waals equation nonideal gas P + (V – nb) = nRTan2 V2( ) } corrected pressure } corrected volume
  • 59. Gases
  • 60. Gases