Chapter 10 Temperature and Heat. What are temperature and heat?. Are they the same? What causes heat?. What Is Temperature?. How do we measure temperature? What are we actually measuring?. Temperature and Its Measurement. How do we measure temperature?
Are they the same? What causes heat?
How do we measure temperature?
What are we actually measuring?
Zeroth law of thermodynamics.
Water freezing point: 32F
Water boiling point: 212F
Water freezing point: 0C.
Water boiling point: 100C
Water freezing point: 0C =273.2 K.
Water boiling point: 100C = 373.2 K
It is a property of the material, determined by experiment.
Table 10.1 Specific capacity of some common substances
Substance Specific Heat Capacity (in Cal/g/C)
Ethyl alcohol 0.58
When a material’s temperature is changed, we can calculate how much heat absorbed/released by the material:
Q = mcT
where Q = quantity of heat
m = mass
c = specific heat capacity
T = change in temperature
How much heat is required to raise the temperature of 70g of water from 20C to 80C
Heat is the energy that flows from one object to another when there is a difference in temperature between the objects. Heat is the average kinetic energy of atoms or molecules making up the system.
Temperature is an indication
of whether or not and in which
direction, the heat will flow
(Temperature is an indication
of the average of kinetic energy
of atoms or molecules).
If the specific heat capacity of ice is 0.5 cal/gC°, how much heat would have to be added to 200 g of ice, initially at a temperature of -10°C, to (a) raise the ice to the melting point?(b) complete melt the ice?
1 cal = 4.19 J
Energy Conservation - In an isolated system, the total amount of energy, including heat, is conserved.
a) What is the increase in
internal energy of the
b) How much ice melts in
1 Cal =1,000 cal
a) the temperature difference between the objects.
b) the thermal conductivity of the materials, a measure of how well the materials conduct heat.
Convection: heat is transferred by the motion of a fluid containing thermal energy.
Example: Suppose that you have 100 g of water at
the temperature of 20 C, and you have 50 g of a
metal at the temperature of 100 C. If you put the
metal into the water, and the final temperature is
30 C when the mix of water and aluminum reaches
a thermal equilibrium, what is the specific capacity
of the metal?