Heat, Temperature and Matter
Heat and Temperature
Think about what you understand the relation between heat and
temperature to be. Describe the process of heating an object in terms of
what is happening to temperature.
Demonstration: Heating water with electric heaters.
Data:
mass(g)
time (s)
watts
 Energy
150
60
300
60
300
120
Exploration for patterns:
mass(g)
 T (°C)
150
300
300
Discussion notes:
m•T
1
 E = heat
 T (°C)
 E / (m T)
Gas Pressure vs. Temperature demo.
Sketch, description of apparatus
V = 4/3  r3 = 4(3.1416)/3 (
)3 =
T (°C)
P (psi)
Graph of results:
Discussion:
Relationships P, T :
mass, T, E:
2
Particle model:
Mass comes in particles;
twice the mass = twice as many particles (same material).
mass / (Molecular weight) = number of moles of particles (big dozen).
Since our gas sample in the demo didn’t change height, the only energy
which can increase for point masses is the kinetic energy (provided they are
not magnetic, have zero net electrical charge, .... which are normally true).
mass, T, E relation:
P, T relation:
One atmosphere ≈ 101 kPa = 101 kN/m2 = 14.7 psi
Temperatures in energy calculations are always in Kelvin = 0 K at absolute
zero and 1 K = 1°C in size.
PV/T =
From Chemistry, we know that 22.4 Litres of gas at 0°C and one atmosphere
pressure contains one mole of particles.
Calculate number of particles in bulb by n = V/22.4 L =
moles.
Calculate PV/(nT) =
3