13 temperature and ideal gases
DESCRIPTION
13 Temperature and Ideal Gases. Homework: Problems: 1, 7, 41. Thermal Equilibrium Temperature Scales Ideal Gases Thermal Expansion. Temperature. T ~ avg. KE/molecule Thermal Expansion Scales: Kelvin, K C° = K – 273 F° = (9/5)C° + 32. 2. Thermal Equilibrium. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/1.jpg)
13 Temperature and Ideal Gases
• Homework:
• Problems: 1, 7, 41.
• Thermal Equilibrium
• Temperature Scales
• Ideal Gases
• Thermal Expansion
1
![Page 2: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/2.jpg)
22
Temperature
• T ~ avg. KE/molecule
• Thermal Expansion
• Scales:
• Kelvin, K
• C° = K – 273
• F° = (9/5)C° + 32
![Page 3: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/3.jpg)
Thermal Equilibrium
• Heat flows from hotter object to cooler object.
• When the heat flow ceases the objects are in thermal equilibrium.
• Objects in thermal equilibrium are at the same temperature.
• /
3
![Page 4: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/4.jpg)
Ideal Gas
4
1
11
2
22 :gas ideal confined a of states ComparingT
VP
T
VP
re temperatu x volumepressure
:Equation Gas Ideal
TPV
068.11
1
20273
40273
:offactor aby increases pressure The 40C. to20C
from olumeconstant vat heated is gas idealAn
2
1
1
2
1
2
V
V
T
T
P
P
![Page 5: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/5.jpg)
5
Gas Thermometer
• PV ~ NT• P ~ T (V, N constant)
• Gas cools,
• avg. KE 0,
• (absolute zero),
• P 0,
• ≈ -273 °C
![Page 6: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/6.jpg)
6
Constant Pressure
• What % increase in V occurs for an ideal gas heated from 20C to 40C? (V ~ T)
• (It does not double, b/c C is not a thermodynamic temperature scale)
• V2/V1 = T2/T1 = (273+40)/(273+20) = 1.068
• 6.8% increase in volume.
![Page 7: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/7.jpg)
7
L = Lo T
Linear Thermal Expansion
Example: 100C increase in Aluminum causes a fractional increase in length of 0.0024 = 0.24% change.
![Page 8: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/8.jpg)
8
Bi-Metallic Strips
![Page 9: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/9.jpg)
Summary
• Thermal Equilibrium
• Temperature Scales
• Ideal Gases
• Thermal Expansion
9
![Page 10: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/10.jpg)
1010
Water Expansion• Expansion from 4°C to 100°C (normal)• Contraction from 0°C to 4°C. (anomalous,
transient ice melting)
![Page 11: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/11.jpg)
1111
![Page 12: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/12.jpg)
12
Superheating
• Mythbusters
12
![Page 13: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/13.jpg)
Ideal Gases
• N molecules (few intermolecular collisions)
• v = average speed
• P due to wall-collisions (P ~ Nv/t)
• t = time between same-wall collision
Lvt 2
v
Lt
2
![Page 14: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/14.jpg)
Ideal gas pressure
A
FP
t
v
A
Nm
A
tvNm
A
FP
/
vmFt
tvmF /
(elastic) 2vv
t
v
A
NmP
2
vLt /2
vL
v
A
Nm
/2
2
AL
Nmv2
![Page 15: 13 Temperature and Ideal Gases](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56812e5d550346895d9404b0/html5/thumbnails/15.jpg)
Ideal Gas Law
t
v
A
NmP
2
vL
v
A
Nm
/2
2
AL
Nmv2
AL) (V KE), avg. ~ (T ~ V
NTP
NTPV ~