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13.10 Kinetic Theory and Temperature

Assumptions: 1. The number of molecules in the gas is

large and they are far apart. 2. The molecules obey Newton’s laws of

motion but move randomly. 3. The molecules interact only by short-

range forces during elastic collisions. 4. The molecules make elastic collisions

with container walls. 5. The gas is pure – all molecules are

identical

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13.10 Kinetic Theory and Temperature

xxxx mvmvmvp 2)(

l

mv

t

pF xx

2

22

3

1vvx

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13.10 Kinetic Theory and Temperature

Compare to ideal gas law: PV = NkT

V

vNm

A

FP

2

3

1

2

2

1

3

2vmNPV

kTKE2

3

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13.11 Kinetic Theory and Temperature

kTmvevN /22

21

m

kTvP

2

m

kTvrms

3

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13.11 Kinetic Theory and Temperature Activation energy and chemical reactions

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13.11 Kinetic Theory and Temperature

Planetary atmospheres

rmsescape vR

GMv 10

2

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13.12 Real Gases and Changes of Phase

Same gas at differenttemperatures

The ideal gas lawprediction and a real gas

Critical point

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13.12 Real Gases and Changes of Phase

WaterCarbon Dioxide

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In class: Problems 47, 92 Other problems ↓

5 32.1atm 1.013 10 Pa atm 8.5 m 167.3 K

1300 mol 8.315 J mol K

PVPV nRT T

nR

55. The temperature of the nitrogen gas is found from the ideal gas law, and then the rms speed is found from the temperature.