Download presentation
Presentation is loading. Please wait.
Published byDale Owen Modified over 9 years ago
1
Chapter 12 Temperature and Heat Temperature – Average kinetic energy of molecules. Heat – Transfer of energy due to temperature difference; flows from hot to cold.
2
12.1 – Common Temp Scales
3
12.2 – The Kelvin Temp Scale
4
12.4 – Linear Thermal Expansion Most materials expand when heated and contract when cooled. The change in length (ΔL) depends on… 1. the material (α) 2. the original length (L 0 ) 3. the temperature change (ΔT) α = coefficient of linear expansion [1/C°]
6
Bimetallic Strip – 2 different metals bonded together. A coiled bimetallic strip can be used in a thermostat
7
Which material has a higher coefficient of linear expansion?
9
12.5 – Volume Thermal Expansion V 0 = original volume [m 3 ] β = coefficient of volume expansion [1/C°] Liquids typically expand more than solids; for most solids, β = 3 α. TABLE 12.1 (p.351)
11
ASSIGN: Ch. 12 #2, 5, 10, 13, 17, 26, 28 p. 375
12
12.6 – Heat & Internal Energy Heat (Q) – transfer of energy due to a temperature difference, naturally flows from hot to cold. Heat is measured in Joules Internal Energy (U) – sum of energy due to molecular motion in a substance. A substance can’t have heat but can have internal energy.
13
12.7 – Specific Heat Capacity Specific Heat Capacity (c) – the heat needed to be supplied or removed to change the temperature of a substance. Table of values on page 359 Heat (J) mass (kg) Specific heat (J/(kg∙C°) Change in temp (°C)
14
When two objects transfer heat with no heat loss to the surroundings…
15
12.7 – Latent Heat Latent Heat – the heat that must be supplied or removed to change the phase of a substance. L f – latent heat of fusion (solid liquid) L v – latent heat of vaporization (liquid gas) L s – latent heat of sublimation (solid gas) Heat (J) mass (kg) latent heat (J/kg) Table of values on page 364
16
12.7 – Latent Heat L f – latent heat of fusion (solid liquid) = 33.5 x 10 4 J/kg = 80 cal/g L v – latent heat of vaporization (liquid gas) = 22.6 x 10 5 J/kg = 540 cal/g Table of values on page 364 For water….
17
12.8 – Equilibrium Between Phases Equilibrium Vapor Pressure – the pressure of the vapor that coexists in equilibrium with the liquid. Boiling Point – the temperature where the vapor pressure of the liquid equals the atmospheric pressure.
18
12.8 – Equilibrium Between Phases Water boils when its vapor pressure equals the atmospheric pressure.
19
ASSIGN: Ch. 12 #41, 44, 45, 51, 52, 62,
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.