Determining the Identity of an
Unknown Metal by Calculating its
Specific Heat and Linear Thermal
Expansion Coefficient
Mohammed Kibria – Fitzgerald High School
Junior Vang – Center Line High School
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Nickel Background
 Discovered by Axel Fredrik Cronstedt
 Nickel silvery-white lustrous metal
 Unreactive with most chemicals and acids
 Malleable and ductile
 Very corrosion resistant metal
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Nickel Background cont.
 One of three magnetic
elements
 Melting point: 2651 °F
(1455 °C)
 [Ar].3d8.4s2
 Common uses:
 Guitar strings, magnets,
rechargeable batteries,
computer hard drives
 Alloys like stainless steel
http://periodictable.com/Samples/028.9/s9s.JPG
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Nickel Background cont.
 Second most believed abundant element in the
earth’s core
 Extraction equation:
50°C
230°C
Ni + 4CO → Ni(CO)4 → Ni + 4CO.
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Terms to Know
 Intensive property – property of a given substance
independent of size of the sample
 First Law of Thermodynamics – States that energy
is neither created nor destroyed, rather is
transferred
 Kinetic Molecular Theory – States that atoms that
are heated become excited, therefore have more
kinetic energy
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Terms to Know cont.
 Specific heat –
 The amount of energy required to raise the temperature
of one gram of a substance by 1°C/K
 Measured in J/g-°C
 Linear thermal expansion –
 Expansion/contraction of metals when heated/cooled
 Described by alpha coefficient (α)
 Measured in mm°C-1
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Problem Statement
To identify an unknown metal rod as nickel or
not by finding its specific heat and linear thermal
expansion coefficient.
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Hypothesis
If the unknown metal rods’ specific heat and
linear thermal expansion coefficient is within a 4%
and 5% error of the values of nickel (respectively),
then the unknown metal will be determined as
nickel.
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Materials: Specific Heat
Calorimeters
LabQuest
Thermometer probe
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Materials: Linear Thermal Expansion
Dial
Metal rod
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Procedure: Specific Heat
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Procedure: Linear Thermal Expansion
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Data Received
 Specific heat averages:
 0.442 J/g°C (known)
 0.453 J/g°C (unknown)
 Linear thermal expansion coefficient averages:
 12.84 mm × 10-6/°C (known)
 13.31 mm × 10-6/°C (unknown)
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Observations
 Trials that resulted in a percent error of 10% or
higher were redone
 Trials with errors that researchers felt effected the
results heavily were redone (i.e., dropping of rod,
bumping jig, calorimeter falling over)
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Percent Error
 Specific heat averages:
 1.71% (known)
 3.03% (unknown)
 Linear thermal expansion coefficient averages:
 -1.239% (known)
 2.3611% (unknown)
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Data Analysis
Two sample t-test:
 Analyzes data from two independent populations
 Tells how likely the data sets come from the same
population
 All assumptions met
▪ SRS, n≥30
 Alpha level of 0.10 was used
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Data Analysis cont.
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Data Analysis cont.
H0: µ1 = µ2
Ha: µ1 ≠ µ2
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Data Analysis cont.
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Data Analysis cont.
Results from the t-test on specific heat trials:
H0: µ1 = µ2
Ha: µ1 ≠ µ2
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Data Analysis cont.
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Data Analysis cont.
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Data Analysis cont.
Results from the t-test on specific heat trials:
H0: µ1 = µ2
Ha: µ1 ≠ µ2
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Data Analysis cont.
 The tests state that the specific heats of the rods
may not be the same, yet the linear thermal
expansion coefficients may be the same.
 Using nickel’s magnetic property to determine the
identity of the unknown rod
 Nickel rod reacted with the magnet
 Unknown rod did not react with the magnet
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Conclusion
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Conclusion cont.
Why?
 Unknown rods were not identified as nickel using the
calculated specific heat and linear thermal expansion
coefficient
 One t-test yielded results that suggested metals were
not the same, but the other did not.
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Design Flaws
 Rods were assumed the same temperature of the boiling
water when heated
 Rods were assumed the same temperature as the room’s
temperature when cooling
 Jigs were made out of wood
 Use of metal tongs
 Calorimeters absorbing some energy
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Recap
Researchers:
 Were given an unknown metal sample
 Conducted two experiments to calculate two
intensive properties
 Used two-sample t-tests to statistically analyze the
results from the experiment
 Made an educated conclusion on the unknown
rods’ identity based on results of analysis
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Recap cont.
Using magnets to finally determine, the metals were
not the same
 One was magnetic while the other was not
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Real World Application
 Manufacturers can identify scrap metals
 Entrepreneurs need ways to identify metal
samples
 Finding the most effective metal/metal alloy to
design car parts, bridges, buildings, computers,
and more
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Acknoweldgements
 Mr. Mark Supal
 Mrs. Hilliard
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Bibliography
Katya. "PriMetals." PriMetals. 2009. 24 Mar. 2013
<http://www.primetals.com/index.php?option=com_content>.
"ELEMENT: NICKEL." ELEMENT: NICKEL. 24 Mar. 2013
<http://www.radiochemistry.org/periodictable/elements/28.html>.
Gagnon, Seteve. "The Element Nickel." It's Elemental -. 24 Mar. 2013
<http://education.jlab.org/itselemental/ele028.html>.
Bentor, Yinon. Chemical Element.com - Nickel. Mar. 24, 2013
<http://www.chemicalelements.com/elements/ni.html>.
"Nickel." Chemistry Reference. 24 Mar. 2013
<http://www.chemistryreference.com/pdictable/q_elements.asp?Symbol=Ni>.
Mond, L.; Langer, K.; Quincke, F. (1890). "Action of carbon monoxide on nickel". Journal of the Chemical
Society 57: 749–753
John Trowbridge and Samuel Sheldon, Proc. Am. Acad. Arts Sci. 24, 181-184 (1889)
Housecroft, C. E.; Sharpe, A. G. (2008). Inorganic Chemistry (3rd ed.). Prentice Hall. p. 729.
Weeks, Mary Elvira (1932). "The discovery of the elements: III. Some eighteenth-century metals". Journal of
Chemical Education 9: 22.
"The Extraction of Nickel from its Ores by the Mond Process".Nature 59 (1516): 63. 1898.
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Bibliography
"Specific Heat Experiment." Specific Heat Experiment. N.p., n.d. Web. 26 Mar. 2013.
<http://www.chem.uiuc.edu/webfunchem/specificheat/specificheat.htm>.
"Tantalum Products." Tantalum Products. H Cross Company, n.d. Web. 24 Mar. 2013.
<http://www.hcrosscompany.com/refractory/tantalum.htm>.
"Thermal Expansion of the Elements." Thermal Expansion for All the Elements in the Periodic Table. N.p.,
n.d. Web. 24 Mar. 2013. <http://www.periodictable.com/Properties/A/ThermalExpansion.html>.
"Thermal Expansion - Linear." Thermal Expansion - Linear. The Engineering Toolbox, n.d. Web. 19 May
2013. <http://www.engineeringtoolbox.com/linear-thermal-expansion-d_1379.html>.
"What Are the Chemical Element Tantalum's Physical Properties?" Www.sciencedaily.com. About Science
Daily, n.d. Web. 24 Mar. 2013. <http://chemical-elements.sciencedaily.com/q/93/7956/Whatare-the-chemical-element-Tantalum-s-physical-properties>.
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Questions?
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