Pre-Lab 11B: Specific Heat of
a Metal
Purpose
If you have ever walked barefoot on a concrete walkway
or street during the summertime, you have felt its
warmth on your feet. In fact, the thermal energy
transferred to your feet may send you retreating to the
grass or even a swimming pool.
Why is the temperature of the concrete so different
compared to the temperature of the soil or the
swimming pool?
Even though the sunlight shines on all three surfaces, it
is easier to raise the temperature of concrete
compared to the water in a swimming pool.
A hot summer day may only raise the temperature in a
pool by one or two degrees.
• In this lab many changes have been made,
they will be in bold, underlined and in the
color green.
• In this experiment, you will use a calorimeter,
the specific heat of water, and the law of
conservation of energy to determine the specific
heat of a sample of steel washers and one
gold unknown metal sample.
Key Question
• How can you use specific heat to identify
an unknown metal sample?
Background
• Define:
– Specific heat
– Formula % error
– Formula for energy
Drawing
• Draw a calorimeter
Procedure
Do all the experiment on the first metal and
then, and only then, move on to the next
metal.
Follow this lab absolutely exactly and a
quickly as possible: time is critical!!
Section 1:
1) Use four steel washers
2) Make a calorimeter
3) fill calorimeter 3/4 with room temperature water (not tap
water)
Mass the water: remember how to find the mass of only
the water (tare mass)?
4) Omit
5) -Place a 400 ml beaker w/ 3/4 water on a hot plate,
heat to boiling.
-The ring stand, lower 4 washers on the hook into the
beaker of boiling water, they do not touch the glass
-Heat washers for 5 minutes.
6) Measure the temperature of the boiling water and record
as initial temperature of metal.
7) Measure temp of calorimeter water: record
8) As quickly as possible, remove the hook
w/washers from the hot water/shake and
slide only washers into the calorimeter, no
splashing
close the calorimeter, place thermometer in
hole in the top. Slide the thermometer up
and down in the calorimeter GENTLY.
9) Once temperature stabilizes, record.
10) Repeat steps 1-9 for only one second metal:
gold cube.
-place a large rubber stopper in the
beaker which is on the hot plate
-place the gold cube on the rubber
stopper
-use tongs to get gold cube out of boiling
water, do not use the hook method
Data chart: “mass and temperature data”
replace copper w/ steel
3 columns: eliminate the second unknown
Section 2:
a. Is the temperature change of calorimeter water
c. Use heat equation solve for E of water:
what is the equation?
Ew = Mw Cpw (T2w –T1w)
where do you get the Cp of water?
Section 2:
Name of Substance
Aluminum
Brass
Copper
Nickel
Iron
Steel
Water
Zinc
Specific Heat, J/g °C
0.899
0.380
0.385
0.443
0.449
0.470
4.184
0.388
d. SHOW YOUR WORK:
This is a key point:
energy released by the metal is equal to the
energy absorbed by the water:
Ew = Em
now knowing the value of E for the metal (Em),
calculate the specific heat (Cp) of the metal:
Em = Mm Cpm (T2m –T1m) so isolate Cpm: how?
Remember, since the energy is being released
by the metal, the Cp value will be negative =
loss of heat
f. % error = (calculated – actual) x 100
Because there are two metals record as this:
Lines a through d, use a two column entry
system and show your work
e. see front board for known Cp metals
Section 3:
b: use only your data (not the class data)
d: Omit
Post Lab: Lab 11B: Specific Heat of
a Metal
Purpose
If you have ever walked barefoot on a concrete walkway or
street during the summertime, you have felt its warmth
on your feet. In fact, the thermal energy transferred to
your feet may send you retreating to the grass or even a
swimming pool.
Why is the temperature of the concrete so different
compared to the temperature of the soil or the swimming
pool?
Even though the sunlight shines on all three surfaces, it is
easier to raise the temperature of concrete compared to
the water in a swimming pool.
A hot summer day may only raise the temperature in a
pool by one or two degrees.
Key Question
• How can you use specific heat to identity
an unknown metal sample?
Background
• Define:
– Specific heat
– Formula for energy
– Formula % error
Knowing the value of E for the metal,
calculate the specific heat (Cp) of the
metal.
Identify your unknown metal(s) by
comparing your calculated value of its
specific heat to known specific heat values
of common metals provided by your
teacher.
Calculate the percent error for your unknown
sample(s).
b. Looking at your data, were the experimental values
too high or too low? Based on the experimental
procedure, give an explanation for your
observations.
c. How does the Law of Conservation of Energy
allows us to make the calculations needed to
determine the specific heat of the mystery metal?
e. Water has a high specific heat. How does the fact
that humans are largely made up of water help us
regulate our body temperature