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Determining the Identity of an Unknown Metal by Calculating its Specific

Heat and Linear Thermal Expansion Coefficient

Mohammed Kibria – Fitzgerald High SchoolJunior Vang – Center Line High School

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Discovered by Axel Fredrik Cronstedt

Nickel silvery-white lustrous metal Unreactive with most chemicals and acidsMalleable and ductileVery corrosion resistant metal

Nickel Background

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One of three magnetic elementsMelting point: 2651 °F (1455 °C)[Ar].3d8.4s2Common uses:

Guitar strings, magnets, rechargeable batteries, computer hard drivesAlloys like stainless steel

Nickel Background cont.

http://periodictable.com/Samples/028.9/s9s.JPG

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Second most believed abundant element in the earth’s core

Extraction equation:

  50°C 230°C Ni + 4CO → Ni(CO)4 → Ni + 4CO. 

Nickel Background cont.

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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

Terms to Know

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Specific heat – The amount of energy required to raise the temperature of one gram of a substance by 1°C/KMeasured in J/g-°C

Linear thermal expansion – Expansion/contraction of metals when heated/cooledDescribed by alpha coefficient (α)Measured in mm°C-1

Terms to Know cont.

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To identify an unknown metal rod as nickel or not by finding its specific heat and linear thermal expansion coefficient.

Problem Statement

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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.

Hypothesis

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LabQuest

Thermometer probe

Calorimeters

Materials: Specific Heat

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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 ReceivedSpecific 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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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)

Observations

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Percent ErrorSpecific heat averages:

1.71% (known) 3.03% (unknown)

Linear thermal expansion coefficient averages: -1.239% (known) 2.3611% (unknown)

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Two sample t-test:Analyzes data from two independent populations Tells how likely the data sets come from the same populationAll assumptions met

SRS, n≥30Alpha level of 0.10 was used

Data Analysis

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Data Analysis cont.

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H0: µ1 = µ2

Ha: µ1 ≠ µ2

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 = µ2Ha: µ1 ≠ µ2

Fail to reject H0 at α =

0.10

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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 = µ2Ha: µ1 ≠ µ2

Reject H0 at α = 0.10

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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 magnetUnknown rod did not react with the magnet

Data Analysis cont.

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Conclusion

REJECTED

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Why? Unknown rods were not identified as nickel using the calculated specific heat and linear thermal expansion coefficientOne t-test yielded results that suggested metals were not the same, but the other did not.

Conclusion cont.

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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

Design Flaws

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Researchers:Were given an unknown metal sampleConducted two experiments to calculate two intensive propertiesUsed two-sample t-tests to statistically analyze the results from the experimentMade an educated conclusion on the unknown rods’ identity based on results of analysis

Recap

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Using magnets to finally determine, the metals were not the sameOne was magnetic while the other was not

Recap cont.

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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

Real World Application

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AcknoweldgementsMr. Mark Supal

Mrs. Hilliard

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BibliographyKatya. "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/What- are-the-chemical-element-Tantalum-s-physical-properties>.

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Questions?

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