Matthew DeSantis – Cousino High School

 Terms To Know Terms To Know  Introduction Introduction  Specific Heat Specific Heat  Thermal Expansion Thermal Expansion  Cobalt Background Cobalt Background  Problem Statement Problem Statement  Hypothesis Hypothesis  Data Measured Data Measured  Materials Materials  Procedure Procedure  Statistical Analysis Statistical Analysis  Conclusion Conclusion

 Calorimetry  Calorimeter  Jig  P-value  Alpha Level  Alpha Coefficient  Standard Error

Cobalt’s name originates from Kobolds, a German goblin that haunted mines. The cobalt, or kobold, ore was thought to be precious silver, but contained arsenic, which produced a deadly gas when smelted.

Cobalt is one of 4 ferromagnetic metals, along with Nickel, Gadolinium and Iron. These elements have similar physical attributes, yet they have different intensive properties. CobaltNickel IronGadolinium

Cobalt was discovered to be a new substance by Georg Brandt in 1735, who later proved it to be a new element rather than a different metal compound.

Cobalt’s most common use is its trademark blue color, which is used in dyes, pottery and paintings. It is also used as wear resistant metal and is magnetic when alloyed.

Cobalt is most frequently found alongside copper and nickel and also usually contains significant amounts of arsenic and sulfur. It is usually mined in Congo and Zambia. Cobalt is extracted from nickel-cobalt ore by adding ammonia and separation using hydrogen.

Specific Heat is the amount of heat to raise a certain mass of a material by one degree Celsius. Units are J/g * C°

Thermal Expansion is the proportion of the change in length of a material when the temperature is raised or lowered to the original length. Units are mm/mm °C or °C -1

Can an unknown metal be differentiated from a sample of cobalt using two intensive properties like linear thermal expansion and specific heat?

If a metal rod is analyzed using linear thermal expansion and specific heat, then it will be identified correctly as a different metal within 10% error for specific heat and within 15% error for linear thermal expansion.

TrialRod Initial Length (mm) Δ L (mm) Initial Temperature (C°) Final Temperature (C°) Alpha Coefficient (mm x ) Percent Error Observations 14B Moving was completed quickly, little spraying was done TrialRod Initial Length (mm) ΔL (mm) Initial Temperature (C°) Final Temperature (C°) Alpha Coefficient (mm x ) Percent Error Observations 3A The rod was cooled in the air for much longer before being placed in the jig Unknown Metal Rod Known Metal Rod

TrialRod Initial Temperature (C°) Final Temperature (C°) Temperature Change (C°) Mass (g) Specific Heat (J/g x C°) ObservationsPercent Error WaterMetal Wat er MetalWaterMetal 1B First Trial, water heated more than in other trials, less water used Known Metal Rod TrialRod Initial Temperature (C°) Final Temperature (C°) Temperature Change (C°) Mass (g) Specific Heat (J/g x C°) ObservationsPercent Error WaterMetalWaterMetalWaterMetal 6B Calorimeter’s base fell apart due to stress, Trial had to be redone Unknown Metal Rod

Known Unknown

Known Unknown

H o The Null Hypothesis (Known = Unknown) H a The Alternative Hypothesis (Known ≠ Unknown)

Due to the P-values of both the specific heat and the and the linear thermal expansion being less than the given alpha level of 0.1, the null hypothesis was… Rejected!

The hypothesis was accepted, as both experiments proved that the two pairs of metal rods were significantly different. The P-value of both tests were less than the given alpha level of 0.1, leading to the null hypothesis being rejected and showing that the two metals are not the same metal.

 One calorimeter collapsed during a trial, and a backup had to be used. This could be because the calorimeters were only insulated on their sides, but not the bottom.  Inaccuracies in the wooden jig  High standard error in Linear Thermal Expansion.

 A greater number of trials  Jigs made out a different material  Calorimeters construction  Longer length of rod to isolate lengths better.

 Thermal Expansion is widely used in engineering and architecture, as different materials expand and contract with temperature change.  Specific Heat is also used for these, and for the construction of automobiles and buildings to withstand extreme temperatures.

Mrs. Hilliard for help in the lab and clarification Mr. Supal for help in construction of calorimeter Mrs. Dewey for help on Data Analysis

 Helmenstine, A.. N.p.. Web. 19 May  Lenntech,. N.p.. Web. 19 May  Somika,. N.p.. Web. 19 May

 Taylor, J. C., and R. S. Young . N.p.. Web. 19 May .

 Chemicool.com, N.p.. Web. 19 May . N.p.. Web. 19 May  Thomas Jefferson National Accelerator Facility - Office of Science Education,. The Element Cobalt. Web.