Glencoe Chapter 15 :
Sections 1 & 2: Energy
Section One
 Heat
– the energy transferred between
objects that are at different
temperatures.
 Energy
always flows from an area of
high energy to an area of low energy.
 Energy
(J).
is measured in the SI unit joules
 Calories
and British Thermal Unit (BTU)
are also used to measure energy.
 Temperature
– the measure of the
average kinetic energy of the particles
in an object.
 Temperature
is an intensive property.

Heat is an extensive property.
 Enthalpy
(H) – is the sum of the internal
energy of a system plus the product of
the system’s volume multiplied by the
pressure that the system exerts on its
surroundings.
 What
is the relationship between
Enthalpy and average kinetic energy
of the particles inside of it?
What are the Minimum average and
total kinetic energies of the particles at
absolute zero 0.00 K?
Molar heat capacity C measured in
J/K • mol or J/ºC • mol

q = heat n = moles of a substance
ΔT = change in temperature
q = n C ΔT
heat = (amount in moles)(molar heat capacity)(change in temperature)

Table 15.2 on Page 520
 Molar
Heat Capacity vs. Specific Heat
specific heat Cp of a substance is the
energy needed to raise the
temperature of one gram of a
substance by one kelvin.
Molar heat capacity is related to the
number of moles of a substance.
(molar
mass)(specific heat) = molar heat capacity
M (g/mol) * Cp (J/K • g) = C (J/K • mol)
The higher the temperature the higher
the enthalpy and the higher the kinetic
energy of the particles.
