chap 18. heat and the 1st law of...
TRANSCRIPT
![Page 1: Chap 18. Heat and the 1st law of Thermodynamicscontents.kocw.net/KOCW/document/2013/korea/chayjunegone1/... · 2016. 9. 9. · nMv2 rms rms 3RT 2) nmNA 2 nM(v2) x avg avg nM(v avg](https://reader034.vdocuments.net/reader034/viewer/2022052502/60a12cfb02a20323183cdb35/html5/thumbnails/1.jpg)
Copyright statement
• The images and the pictures in this lecture are provided by the CDs accompanied by the books
1. University Physics, Bauer and Westfall,
McGraw-Hill, 2011.
2. Principles of Physics, Halliday, Resnick,
and Walker, Wiley, 8th and 9th Ed.
• The rest is made by me.
![Page 2: Chap 18. Heat and the 1st law of Thermodynamicscontents.kocw.net/KOCW/document/2013/korea/chayjunegone1/... · 2016. 9. 9. · nMv2 rms rms 3RT 2) nmNA 2 nM(v2) x avg avg nM(v avg](https://reader034.vdocuments.net/reader034/viewer/2022052502/60a12cfb02a20323183cdb35/html5/thumbnails/2.jpg)
isothermal process
T= constant (DE = 0) ; DQ = DE + DW
p
V
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adiabatic process
DQ =0 ; DQ = DE + DW
p
V
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constant-volume process
DW =0 ; DQ = DE + DW
p
V
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cyclic process
DE =0 ; DQ = DE + DW
p
V
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free expansion
DQ =0, DW =0 ; DQ = DE + DW
p
V
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Sample prob. (a) 계가 한 일
(b) 열로 전달된 에너지
(c) 내부에너지 변화량
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Problem
각 과정에서 기체가 한 일은?
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Problem
ab, bc를 따라갈 때 전달된 열에너지는?
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Ch. 19 Ideal gases
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Avogadro’s number
• 1 NA = 1 mole을 이루는 원자 또는 분자의 개수
= 6.02 x 1023
= C12 12 gram 안에 들어 있는 탄소원자의 수
• 원자 수준의 미시적 세계와 거시적 세계 간의 환산인자
• It is a very very large number.
大數의 법칙
몰 수 n
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ideal gas
• 질점 (내부구조나 부피 없이 질량만 있는 입자)으로 구성되어 있다.
• 분자-분자간의 상호작용은 탄성충돌 뿐이다.
(서로 잡아 당기거나, 밀치지 않는다.)
* 밀도가 낮은 단원자 분자로 구성된 기체가 가장 근사한 예
nRTpV
• 이상기체 상태방정식 :
KJ/mole1038.1
KJ/mole31.8
23
AN
Rk
R
TNkpV
Boltzmann 상수
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이상기체의 등온팽창
참고: 등적과정 등압과정
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압력, 온도 및 rms 속력
입자 한 개가 충돌할 때 운동량 변화
입자의 왕복시간
평균 단위시간당 전달된 선운동량
개
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Translational kinetic energy
Mean free path