the ideal gas ideal gas law van der waals equation distribution of molecular speeds
TRANSCRIPT
The Ideal GasThe Ideal Gas
Ideal Gas LawIdeal Gas Law
Van der Waals EquationVan der Waals Equation
Distribution of Molecular SpeedsDistribution of Molecular Speeds
Reading QuestionReading QuestionWhat is the SI unit of pressure?
1. The Nm2 (Newton-meter-squared)2. The atmosphere3. The p.s.i. 4. The Pascal5. The Archimedes
Reading QuestionReading QuestionWhat is the SI unit of pressure?
1. The Nm2 (Newton-meter-squared)2. The atmosphere3. The p.s.i. 4. The Pascal5. The Archimedes
Reading QuestionReading Question
The ideal gas model is valid if
1. the gas density is low. 2. the gas density is high. 3. the temperature is low.4. the gas pressure is large.5. none of the above
Reading QuestionReading Question
The ideal gas model is valid if
1. the gas density is low. 2. the gas density is high. 3. the temperature is low.4. the gas pressure is large.5. none of the above
Reading QuestionReading Question
An ideal-gas process in which the volume doesn’t change is called
1. isobaric.2. isothermal.3. isochoric.4. isentropic.
Reading QuestionReading Question
An ideal-gas process in which the volume doesn’t change is called
1. isobaric.2. isothermal.3. isochoric.4. isentropic.
The Ideal GasThe Ideal GasHeat of Transformation• Heat of fusion – the heat to transform a gram of substance from solid to liquid.
• Heat of vaporization – the heat to transform a gram of substance from liquid to gas.
• Sublimation – solid to gas
Slope heat capacity
Q time
Qf = mLf
Qv = mLv
The Ideal GasThe Ideal Gas
SubstanceSubstance Melting Melting point, Kpoint, K
Lf, kJ/kgLf, kJ/kg Boiling Boiling point, Kpoint, K
Lv, kJ/kgLv, kJ/kg
AlcoholAlcohol 159159 109109 351351 879879
CopperCopper 13571357 205205 28402840 47264726
MercuryMercury
OxygenOxygen 54.854.8 13.813.8 90.290.2 213213
SulfurSulfur
WaterWater 273273 334334 373373 22572257
Heat of TransformationHeat of Transformation
The Ideal GasThe Ideal Gas
Sublimation
Boiling
Phase DiagramPhase Diagram
The Ideal GasThe Ideal Gas• Phase Diagram for Water
The Ideal GasThe Ideal Gas
Student WorkbookStudent Workbook
freezing point at temperature T
triple point
boiling point at pressure p
critical pointsublimation at pressure p
Student WorkbookStudent Workbook
boiling point temperature decreases
Class QuestionClass QuestionWhen you warm up CO2 or dry ice it goes directly from a solid to a gas. This processes is called
1. critical point2. sublimation3. isochoric processes4. isentropic processes5. None of the above.
Class QuestionClass QuestionWhen you warm up CO2 or dry ice it goes directly from a solid to a gas. This processes is called
1. critical point2. sublimation3. isochoric processes4. isentropic processes5. None of the above.
The Ideal GasThe Ideal GasThe Ideal Gas LawThe Ideal Gas Law
NkTPV • P pressure exerted by the gas (Pa)• V volume of the gas• N number of molecules in the gas (m3)• T temperature of the gas (K)• k = 1.38X10-23 J/K Boltzmann’s constant
Most real gases obey this law with very slight deviations
A mole is 6.022X1023 molecules. nRTPV • R = NAk = 8.314 J/Kmole universal gas constant
The Ideal GasThe Ideal Gas Quasi-static and Irreversible ProcessesQuasi-static and Irreversible Processes
The Ideal GasThe Ideal Gas Isochoric ProcessesIsochoric Processes
The Ideal GasThe Ideal Gas Isobaric ProcessesIsobaric Processes
The Ideal GasThe Ideal Gas Isothermal ProcessesIsothermal Processes
The Ideal GasThe Ideal Gas Isothermal ProcessesIsothermal Processes
Student WorkbookStudent Workbook
w
atmF
0netF
because the liquid is not accelerating
the pressure is less.
Student WorkbookStudent Workbook
NkTPV pVT
Nk
22
2
11
1
VpT
VpT
11
2
11
1
23 VpT
VpT
12 6TT
Student WorkbookStudent Workbook
NkTpV VTp
Nk
22
2
11
1
VpT
VpT
12
1
11
1
32
VpT
VpT
12 32
pp
Student WorkbookStudent Workbook
Student WorkbookStudent Workbook
isochoric isothermal isobaric
00
011
Student WorkbookStudent Workbook
NkTpV
Class QuestionClass Question
1. Thelium < Tnitrogen
2. Thelium = Tnitrogen
3. Thelium > Tnitrogen
4. There is not enough information
You have two containers of equal volume. One is full of helium gas. The other holds an equal mass of nitrogen gas. Both gases have the same pressure. How does the temperature of the helium compare to the temperature of the nitrogen?
Class QuestionClass Question
1. Thelium < Tnitrogen
2. Thelium = Tnitrogen
3. Thelium > Tnitrogen
4. There is not enough information
You have two containers of equal volume. One is full of helium gas. The other holds an equal mass of nitrogen gas. Both gases have the same pressure. How does the temperature of the helium compare to the temperature of the nitrogen?
Class QuestionClass Question
What is the ratio Tf /Ti for this process?
1. 42. 23. 1 (no change)
4.
5.
Class QuestionClass Question
What is the ratio Tf /Ti for this process?
1. 42. 23. 1 (no change)
4.
5.
The Ideal GasThe Ideal GasKinetic Theory of the Ideal GasKinetic Theory of the Ideal Gas
The Ideal GasThe Ideal GasKinetic Theory of the Ideal GasKinetic Theory of the Ideal Gas
KvmkT
2
21
23
mkT
vthermal
3
vevkT
mNvvN kT
vm
2
21
2
23
24)(
The Ideal GasThe Ideal GasReal GasesReal Gases
Van der Waals Equation
kTnbVV
anP
2
2
Takes into account1. Size of the molecules2. Interaction between the molecules