10.3.1 Specific Heat and Calorimetry
Date, Section, Pages, etc.
Mr. Richter
Agenda
 Check and Review HW
 Warm Up
 Intro to Specific Heat
 Notes:
 Specific Heat Capacity
 Calorimetry
 Practice Problems
Objectives: We Will Be Able To…
 Define specific heat capacity.
 Perform calculations with specific heat capacity.
 Understand the process of calorimetry and perform
calorimetry calculations.
Warm-Up:
 When you go to the beach in the summer, the sand is often
much hotter than the adjacent water. Why is this?
 Discuss at your table, and we will discuss as a class in a few
minutes.
Specific Heat Capacity
Specific Heat Capacity
 All substances have different molecular structures due to
either:
 different elements, or
 different arrangements of atoms
 As a result, different substances require different amounts of
energy to raise their temperatures.
 Generally, a substance’s specific heat capacity is the amount
of energy required to raise the temperature of an object.
Specific Heat Capacity
 What factors will determine how much energy is required to
raise the temperature of a substance?
 the mass (how much)
 the difference in temperature
 “Specifically”: specific heat capacity is the quantity of
energy needed to raise the temperature of 1 kg of a
substance by 1 °C (at constant pressure)
 Units:
J
kg oC
Specific Heat Capacity p.372
Specific Heat Capacity
Q = Cp mDT
Specific Heat Capacity: Practice
Problem
 How much energy is required to raise the temperature of
15.0 kg of water by 20.0 °C?
 Q = (4186)(15.0)(20.0)
 Q = 1.26 x 106 J
Calorimetry
How is specific heat determined?
Calorimetry
 The specific heat capacity of water has been studied
extensively and is well known.
 Cp,water = 4186 J/kg °C
 Scientists can use the principles of calorimetry and the
specific heat capacity of water to determine the specific heat
capacities of other substances.
 Calorimetry is the experimental procedure used to
measure the energy transfer from one substance to another
as heat.
Calorimetry: How it works
 Place an object with
 a known mass
 known temperature
 unknown specific heat
 Into a container of water
with:
 a known mass
 known temperature
 known specific heat
 When these reach thermal
equilibrium, you will know:
 how much energy the
water absorbed, which is
equal to…
 how much energy the
object lost
 From this you can determine
the specific heat capacity of
the substance.
Calorimetry
 Heat absorbed by water =
heat released by object.
Qw = Qx
c p,w mw DTw = cp,x mx DTx
Practice Problem
 A 0.050 kg metal bolt is heated to an unknown initial
temperature. It is then dropped into a beaker containing
0.15 kg of water with an initial temperature of 21.0°C. The
bolt and the water then reach a final temperature of 25.0°C.
If the metal has a specific heat capacity of 899J/kg °C, find
the initial temperature of the metal.
 Hint: find the change in temperature of the metal first (solve
for ΔTx, then find the initial temp.
Wrap-Up: Did we meet our objectives?
 Define specific heat capacity.
 Perform calculations with specific heat capacity.
 Understand the process of calorimetry and perform
calorimetry calculations.
Homework
 Due Monday:
 p374 #4, 7