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Using Properties of Zinc to Identify an Unknown MetalJennifer Donovan - Warren MottRyan Gohlke - Sterling Heights
Purpose
• To prove whether the unknown metal rods were Zinc by measuring the specific heat and linear thermal expansion, and comparing it to Zinc’s known values.
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Terms
• Specific Heat – the heat required to raise the temperature of a unit mass of a given substance of a given amount by one degree
• Linear Thermal Expansion – the change in linear dimension, length
• Intensive propertiesDonovan - Gohlke 3
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Terms (continued)• First Law of Thermodynamics – Energy is
neither created nor destroyed, only changed
• Isolated System – system that releases neither energy nor matter
example: Calorimeter
• Kinetic Molecular Theory – Observed when an object is heated up
Background• Initially discovered through ores
• 1374 - eighth metal known to man in that point in time
• 1743 - first European Zinc smelter used a vertical retort procedure
• Zinc production in the United States started in 1850
• Today, U.S. and Canada are leading producers of Zinc
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Retort Procedure• Heating Zinc Sulfide, ZnS, concentrate to 950°C • Produces Zinc Oxide, ZnO• Purer state with process called electrowinning
converting into Zinc Sulfate, ZnSO4
• Separated through electrolysis containing Zinc ions, Zn
ZnS(s) + 3 O2(g) → 2 ZnO(s) + 2 SO2(g)
ZnO(s) + H2SO4(l) → ZnSO4(s) + H2O(l)
2 ZnSO4(s) + 2 H2O(l) → 2 Zn(s) + 2 H2SO4(l) + O2(g)
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Properties of Zinc
• Symbol: Zn• Atomic number: 30• Atomic weight: 65.38• Standard state: solid at 298 K• Electron Structure
1s2
2s22p6
3s23p6
4s2 3d10
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Utilizing Zinc
• Air-batteries • Brass• Countertops• Deodorants• Healing wounds and sore eyes• Paints• Produced in the U.S. one cent penny• Chocolate and cocoa powder
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Why Specific Heat?
• Important quality in the food industry because it determines the amount of energy that must be supplied or withdrawn from a material in order to increase or decrease its temperature by a given amount
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Why Linear Thermal Expansion?
• Gaining knowledge of fluctuating temperatures do not cause the roads and structures to crumble from being expanded easily
Hypothesis
• Zinc will equal unknown metal if the average is less than 5% error • Specific heat of 0.39 (J/g*°C)• Linear thermal expansion coefficient of 3.02 × 10-5 °C-1
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Specific Heat
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Electronic Thermometer
Known/ Unknown
Metal Rods
CalorimetersTemperature Probe
Logger Pro
Specific Heat Procedure
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Specific Heat for Zinc
Trials Rod
Initial Temperatur
e (°C)Equilibriu
m Temperatu
re (°C)
Change in Temperatur
e (°C)
Mass(g)
Specific Heat
(J/g*°C)Water Metal Water Metal Metal
Water
Average N/A
20.4 98.9 23.4 3.0 -75.528.1 65.0
0.385
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Specific Heat Unknown
TrialsRod
Initial Temperature (°C)
Equilibrium
Temperature (°C)
Change in Temperatur
e (°C)Mass(g)
Specific Heat
(J/g*°C)Water
Metal Water MetalMeta
l Wate
r
Average
N/A23.0 99.2 30.2 7.2 -69.0
72.98 65.0 0.389
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Specific Heat
ZincExperimental Value
Percent Error
Average 0.385 -1.37
UnknownExperimental Value
Percent Error
Average 0.389 -0.21
Specific Heat Conclusion• Two-Sample t-test• H0: µz = µu
• Ha: µz ≠ µu
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• Fail to reject H0
• P-value 0.4001 is greater than the alpha level of 0.10
• Evidence the two metals could be the same
• 40.01% chance of having Zinc
Linear Thermal Expansion
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LTE Jig with Dial Measuring 0.01 mm
Known/Unknown Metal Rods
Caliper
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Linear Thermal Expansion Procedure
Linear Thermal Expansion for Zinc
TrialsRod
Final Lengt
h (mm)
Initial Lengt
h (mm)
Net. Chang
e in Lengt
h (mm)
Final Temp. (°C)
Initial
Temp. (°C)
Change in Temp. (°C)
Alpha Coefficient (°C-
1)
Average N/A
129.55
129.39 0.16 24.9 98.9 -74.0
1.691E-05
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Linear Thermal Expansion Unknown
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TrialsRod
Final Lengt
h (mm)
Initial Lengt
h (mm)
Net. Chang
e in Lengt
h (mm)
Final Temp.
(°C)
Initial
Temp.
(°C)
Change in Temp. (°C)
Alpha Coefficient (°C-
1)
Average
N/A132.2
8132.1
4 0.14 23.6 98.8 -75.21.409E-
05
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Linear Thermal Expansion
ZincExperimental Value10-5 °C-1
Percent Error
Average 1.69 -44.01
UnknownExperimental Value10-5 °C-1
Percent Error
Average 1.41 -53.36
Linear Thermal Expansion Conclusion
• Reject H0
• p-value of 0.0000 is less than the alpha level of 0.10
• Evidence the two metals are not the same
• 0% chance the two metals are the same
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• Two-sample t-test• H0: µz = µu
• Ha: µz ≠ µu
Conclusion
• Reject hypothesis•Specific Heat: • Zinc: -1.37% •Unknown: -0.21%• Linear Thermal Expansion:• Zinc: -44.01% •Unknown: -53.36%
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Flaws• Temperature of water in calorimeters was not
constant
• Heat was lost when the metal was transferred from the boiling water to the calorimeter
• When the metal was transferred from the boiling water to the linear thermal expansion jig, the metal rod would shrink in a fractional length before being placed in the jig.
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Limitations
• Time
• Assumption that the heat of the metal was the same as the heat of the water
Further Research
• Density• Melting point• Conductivity
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Acknowledgements• Special thanks to Mr. Koburg
• Thank you to the upper classmen
• Thanks to Mrs. Hilliard, Mrs. Dewey, and Mr. Supal
28Donovan - Gohlke
Works Cited
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Scientific Society. N.p., n.d. Web. 09 May 2013. <http://portal.acs.org/portal/acs/corg/content?_nfpb=true>.Boston University. "Temperature and Thermal Expansion." Temperature and Thermal Expansion. Web. 19 May 2012. <http://physics.bu.edu/~duffy/py105/Temperature.html>.De Leon, N. "Specific Heat." Specific Heat. Tracklit. Web. 19 May
2012.<http://www.iun.edu/~cpanhd/C101webnotes/matter-and- energy/specificheat.html>.Engineering Toolbox, "Metals - Specific Heats." Metals - Specific Heats. N.p., n.d. Web. 24 Mar. 2013. <http://www.engineeringtoolbox.com/specific-heat- metals-d_152.html>.Fine Ceramics World. "Thermal - Thermal Expansion | Characteristics of Fine Ceramics | FINE CERAMICS WORLD - All About Advanced Ceramics." Thermal - Thermal Expansion | Characteristics of Fine Ceramics | FINE CERAMICS WORLD - All About Advanced Ceramics -. N.p., n.d. Web. 07 Apr. 2013. <http://global.kyocera.com/fcworld/charact/heat/thermaexpan.html>."Flame Tests." About.com Chemistry. N.p., n.d. Web. 24 Mar. 2013.
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Haghshenas, Darvishi D. F. EXTRACTION OF ZN, MN AND CO FROM ZNMN-CO-CD-NI CONTAINING SOLUTION USING D2EHPA,CYANEX® 272 AND CYANEX® 302. 2nd ed. Vol. 24. New York:
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International Zinc Association, "History of Zinc." Zinc History. N.p., n.d. Web. 24 Mar. 2013. <http://www.zinc.org/basics/history_of_zinc>.
Kwanga. "Chemistry Lab: Specific Heat of a Metal." Chemistry Lab. Web.
<http://www.kwanga.net/chemnotes/specific-heat-lab.pdf>.St. Louis Community College. "Coefficient of Thermal Linear Expansion." 23 Sept. 1997. Florissant Valley. 7 Apr. 2013 <http://users.stlcc.edu/cburkhardt/sum/lab/thermal.pdf>.Tipler, Paul A. "Thermal Expansion Equations and Formulas Calculator."
Thermal Expansion Equations Formulas Calculator. Worth Publisher. Web. 19 May 2012. <http://www.ajdesigner.com/phpthermalexpansion/thermal_expansio
n_equation_linear_coefficient.php>.TMB. "TMB Plumbing Engineer - Features: November 2006: Thermal Expansion." TMB. Plumbing Engineer. N.p., n.d. Web. 07 Apr. 2013. <http://www.plumbingengineer.com/nov_06/thermal.php>Toolbox. "Thermal Expansion - Linear." Thermal Expansion - Linear. N.p., n.d. Web. 07 Apr. 2013. <http://www.engineeringtoolbox.com/linear- thermal-expansion-d_1379.html>.USEPA, "Primary Metals." Zinc Processing. N.p., n.d. Web. 24 Mar. 2013. <http://www.wmrc.uiuc.edu/info/library_docs/manuals/primmetals/c
hapter7.htm>.
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Any Questions?