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- CHE 101 - Applied Chemistry
A RUBRIC & SAMPLE LAB REPORT
- Formal Lab Report
s must be written
within the following format:
- States the purpose of the lab. – Why the lab is being performed.
- Briefly discusses the concepts or principles of the exercise.
- - What Scientific
Principle ( Law ) will be tested.
- - What Scientific
relationship will be shown.
- The Hypothesis should
be presented here OR as the Aim if applicable.
- - Hypothesis should
include any relationship between variables, should mention the
independent variable vs. dependent variable.
- Background knowledge should be presented here, evidence of further
research into the topic should be done here.
- Describes in enough detail, using numbered steps, the methods and
procedures used in completing the lab exercise. It should be
comprehensive enough for someone to repeat your procedures.
- - Special attention
should be paid to how the independent and the dependant variable
were obtained and recorded, and if there are any constants.
- - The treatment of a
control should also be mentioned.
- This section should NOT contain any recorded results/data from the
- This is where all gathered data is relayed to the reader.
- It should be presented in a clear manner and explained if
- - Tables should be
used and these should mirror the relationship between the variables.
(typically independent on the left in increasing order)
- - Graphs should also
be as detailed, with the independent variable on the x-axis and the
dependent variable on the y-axis.
- Any calculations should be shown here as well. These should
also be presented clearly and explained.
- - The source of all
numbers used in calculations should be given.
- The data, results and procedures will be discussed here.
Explain the relationship of the variables as presented by the data.
Explain any trends in the data that will be used.
You should present the evidence that will support your
conclusion. Percent Error should also be included here as well as
possible sources of the error. Future treatments to reduce error can
be discussed as well.
- States whether the results support your Hypothesis or not, or
whether the scientific principle was demonstrated adequately or not.
Over all Lab
- The report must be typed, neat and stapled. Works used as
reference must be cited**, this includes your textbook.
**For the APA
Page at CCC
- For the MLA:
- University of Illinois at Urbana-Champaign
Chem 101 Spring 2005
The Aim of this Lab Exercise is to show that the composition of a metal
cylinder can be established using a laboratory derived specific heat.
The cylinder’s specific heat was determined indirectly by observing
the temperature change of the water that the cylinder was submerged in.
Submerging the cylinder was necessary due to the fact that we could
not measure the temp of the metal directly.
To calculate a specific heat we used the Heat Equation ( Heat =
(mass) (spec heat) (∆T).
The calculated value of Specific Heat was then compared to a chart of
known Specific Heats. Using
that information and other observable traits of the metal cylinder a
guesstimate was formed for the composition of the cylinder.
This exercise will use the principles
of thermodynamics, when a metal object is submerged in a sample of water,
any heat exchanged from the metal to the water will result in a temperature
change for the water until both water and metal arrive at equilibrium.
When this is done inside an insulated container the heat loss to the
environment is kept to a minimum.
- The following items were used:
- - Calorimeter - the exchange between the metal
cylinder and the water occurred inside the calorimeter to minimize the heat
loss to the environment.
- - thermometer - was inserted into the
- - boiling water bath - the metal cylinder was
originally submerged here, an initial temp of @ 100ºC was achieved
- - metal cylinder of unknown composition
- - laboratory balance that measures to 1/1000 of
a gram to measure the mass of the cylinder and the mass of the water
- Step 1:
In order to
determine the specific heat of the metal cylinder an observable temperature
change was needed, so the cylinder was started in a boiling water bath, a
thermometer measured the temp of the bath to a tenth of a degree Celsius.
- Step 2: Room
temperature water was added to the calorimeter and the Mass of the Water
was found by taking the difference between the ‘mass of the calorimeter
with the water’ and the ‘mass of the empty calorimeter’.
- Step 3:
temperature of the calorimeter and water was allowed to come to equilibrium
the temperature was read and recorded, this was used as the Initial Temp
of the Water.
- Step 4:
temperature of the boiling water bath was recorded before removing the
cylinder, this was used as the Initial Temp of the Cylinder.
- Step 5: The hot metal cylinder was placed quickly
into the calorimeter and the temperature of the water was monitored
with the digital thermometer every 10 seconds for 3 minutes gently swirling
the contents every 20 seconds to avoid areas of differently heated water.
- Step 6: The highest temperature that the water
reached was recorded, this temperature was used as the Final temp of the
Water. ( to avoid using spikes in temp readings, we graphed
the results to obtain our reading from there )
- Step 7:
The Metal Cylinder was removed from the
Calorimeter, dried and its mass was measured.
the metal was fully submerged in the water when it lost its heat we can say
that the heat flowed from the cylinder to only the water.
So it can also be assumed that:
- Assumption – “The heat lost
by the metal is equal to the heat gained by the water. ”
- The heat gained by the water was
calculated first, this was needed to determine the heat lost by the metal
With the value of the Heat Lost by the Metal
the Specific Heat of the Metal can be found using the same
- With the data that was collected the Heat the
Water Gained was found using the equation
H = (m)(Spec.
H = Heat Gained by the Water
m = Mass of the Water =
Specific Heat of Water = 1 cal/g x Cº
- The graph was used to determine the Final
Temperature of the water. (see Fig 1)
= Change in Temp of the Water =
- ( Final
Temp of the Water – Initial Temp of the Water ) =
– 23.2ºC = 2.0Cº
- Heat Water
Gained = ( Mass of Water ) ( Specific Heat of
Water ) ( Change in Temp of
- Heat Water Gained
( 1 cal/g x Cº )
( 2.0Cº )
- Since the metal cylinder was submerged in the
water as they reached that final temp we assumed they were at the same
temperature and thus used the Final temp of the Water as the Final
Temp of the Cylinder.
- As was stated the Heat the Water Gained
will be the same as the Heat the Metal Lost.
- The same formula was used to solve for the Specific
Heat of the Metal.
- H = (m)(Sp. Ht.)(∆T)
- H = Heat Lost by the Metal
- m = Mass of the Metal
Specific Heat of Metal = ?? cal/g x Cº
∆T = Change in Temp of the Metal = ( Final Temp of the Metal
– Initial Temp
- of the Metal ) =
100.2ºC – 25.2ºC = 75.0Cº
- Heat Metal
( Mass of
Metal ) ( Specific Heat of
Metal ) ( Change in Temp of Metal )
( Sp.Ht. )
( 75.0Cº )
Specific Heat of
Metal = 0.094
cal/g x Cº
- The value of Final Temp of the Water/Metal
was determined from the graph. The
spike at time = 30 seconds was ignored as being caused by the thermometer
having too close a proximity to the hot cylinder.
The temperature reading determined by the cooling line was used.
- The measured value for Spec. Heat was then
compared to the list of known Specific Heats(1).
- Laboratory Value =
0.094 cal/g x Cº Some
possible substances (metals) with Known Values from List had specific heat
values equal to 0.095 cal/g x Cº, a difference of
only 0.001 cal/g x Cº seemed within an acceptable
range to consider.
- From the list of known Specific Heats the 3
possibilities were: Brass, Bronze and Copper.
Based on this information and by looking at the cylinder’s other
properties such as color and factors like the expense and likelihood of
Bronze it was determined that the cylinder’s composition was Copper.
The value determined in lab was very close to the value in the Table
of Specific Heat.
%Error = |(Lab Value) – (Known Value)| x100 =
- ( 0.094 cal/g x Cº ) –
( 0.095 cal/g x Cº )
0.1 cal/g x Cº
0.095 cal/g x Cº
0.095 cal/g x Cº
- A % Error of 1.05% is acceptable given the
equipment used. Some possible
sources of error could have been:
- thermometers not accurate or not read properly
- heat lost to the cup and air not factored in
- Overall this exercise should be considered successful.
It was shown that finding the Specific Heat of an unknown substance can be
used to help identify the object’s composition.
- <page break>
Lawliss, M,. Lab Handout- Identifying Materials with Specific Heat, Applied Chemistry-CHE 101 Spring 05
- (1) - CRC Handbook of Chemistry and Physics, 81st Edition (c)1999 CRC
- (2) - Chemistry An Introduction to General, Organic and Biological
Chemistry, Timberlake 8th Edition ... etc
Figure one shows the temperature curve of the water in
the calorimeter when the metal cylinder was placed in the water at time zero.
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