Chapter19 Temperature , Heat , and the First Law of Thermodynamics

Chapter19Temperature , Heat , and the First Law of Thermodynamics

The zeroth law of thermodynamics: If bodies A and B are each in thermal equilibrium with a third body T,then they are in thermal equilibrium with each other. 19-2 The Zeroth Law of Thermodynamics

is the atmospheric pressure, is the density of the mercury in the manometer is the gas pressure now 19-3 Measuring Temperature The Triple Point of Water The Constant – Volume Gas Thermometer P is the pressure within the gas and C is a constant.

A temperature with a gas thermometer is represents a Celsius temperature and T a Kelvin temperature The relation between the Celsius and Fahrenheit scales is 19-4 The Celsius and Fahrenheit Scales

Sample Problem 19-1 19-5 Thermal Expansion

is a constant called the coefficient of linear expansion. Is the coefficient of volume expansion of the solid or liquid. Linear Expansion Volume Expansion Sample Problem 19-2

Definition of heat: Heat is the energy that is transferred between a system and its environment because of a temperature difference that exists between them. 19-6 Temperature and Heat

Heat Capacity and are the initial and final temperatures of the object. Specific Heat Molar Specific Heat 19-7 The Absorption of Heat by Solids and Liquids

The amount of energy per unit mass that must be transferred as heat when a sample completely undergoes a phase change is called the heat of transformation L. The heat of vaporization The heat of fusion Heats of Transformation

(a) Step 1 Step 2 Step 3 (b) Sample Problem 19-3

For the water: For the beaker: For the copper: Sample Problem 19-4

The differential work dW done by the gas during the displacement is The gas to change its volume from Vi to Vf ,the total work done by the gas is 19-8 A Closer Look at Heat and Work

There are actually many ways to take the gas from state i to state f .

The first law of thermodynamics: The internal energy Eint of a system tends to increase if energy is added as heat Q and tends to decrease if energy is lost as work W done by the system. 19-9 The First Law of Thermodynamics

1.Adiabatic processes. 3.Cyclical processes. 2. Constant - volume 4.Free expansions. 19-10 Some Special Cases of the First Law of Thermodynamics

(a) (b) (c) Sample Problem 19-5

Conduction The conduction rate Thermal Resistance to Conduction (R-Value) Conduction Through a Composite Slab 19-11 Heat Transfer Mechanisms

Radiation

Sample Problem 19-6 Sample Problem 19-7

represents a Celsius temperature and T a Kelvin temperature REVIEW & SUMMARY The Kelvin Temperature Scale A temperature with a gas thermometer is Celsius and Fahrenheit Scales The relation between the Celsius and Fahrenheit scales is

is a constant called the coefficient of linear expansion. Is the coefficient of volume expansion of the solid or liquid. and are the initial and final temperatures of the object. Thermal Expansion Heat Heat Capacity and Specific Heat

Where c is the specific heat of the material making up the object. Heat of Transformation Work Associated with Volume Change The gas to change its volume from Vi to Vf,the total work done by the gas is First Law of Thermodynamics The first law of thermodynamics:

The conduction rate Applications of the First Law 1.Adiabatic processes. 3.Cyclical processes. 2. Constant - volume 4.Free expansions. Conduction , Convection , and Radiation

Chapter19 Temperature , Heat , and the First Law of Thermodynamics