Thursday, May 30, 2013
Specific Heat
Purpose:
The purpose of this activity is to determine the specific heat of a metal object and identity the
metal based on its specific heat.
Background:
Specific Heats J/g*c
Water 4.184
Al 0.897
Brass 0.385
Cu 0.385
Lead 0.129
Stainless Steel 0.490
Zn 0.390
In the specific heat lab, you learn how to measure the amount of calories of an unknown metal that were released as the metal is heated in a beaker of water. In order to do this lab, you need to collect the temperatures and masses.
Equation for Specific Heat: Qw = mw*cw*∆Tw
Q is the heat gained. m is the mass. c is the specific heat. ∆T is the change in temperature. For this experiment, we need to plug in the data for both the water and the metal for each trial.
Data:
Trial 1:
Temperature of water: 20.3 C
Temperature of water and metal 20.5 C
Temperature of water and metal (boiled) 99.3 C
Temperature of the metal in Styrofoam 26.0 C
Temperature of the cold water 21.0 C
Mass of beaker 116.84g
Mass of beaker and water 257.73g
Mass of beaker, water and metal 285.71g
Mass of beaker, water and metal (boiling) 271.89g
Mass of the Styrofoam 2.00g
Mass of Styrofoam and water 96.55g
Trial 2:
Temperature of water: 20.1 C
Temperature of water and metal 20.3 C
Temperature of water and metal (boiled) 99.5 C
Temperature of the metal in Styrofoam 20.0 C
Temperature of the cold water 26.3 C
Mass of beaker 116.85g
Mass of beaker and water 231.98g
Mass of beaker, water and metal 278.10g
Mass of beaker, water and metal (boiling) 265.50g
Mass of the Styrofoam 2.00g
Mass of Styrofoam and water 96.55g
Calculations: Qw = mw*cw*∆Tw
Temperature Water changed:
99.3 C - 21.0 C = 78.3 C
Heat water gained:
Q = 94.55 g x 4.184 J/g*C X 78.3 C = 30,975.26
specific heat: for metal
Q = c
m*c
1974.848 J = .897 J/g*c
2022.954 g*c
Analysis:
I learned you can never be too careful when taking measurements. Also, I learned it is best to have a good plan of what will need to be measured, how it will be measured, and the most efficient way to measure it.
Conclusion:
The metal we received was Aluminum because the specific heat matched up perfectly: 0.897.
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Heat water gained = 94,55 g x 4,184 J/gøC X 78.3øC then recalculate specific heat of metal.
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