IB Chemistry SL (8th Period)
03/03/15
Specific Heat of Copper Lab
Background Information and Variables:
This lab focuses on the Thermodynamic principle of Enthalpy (H), which is defined as the internal energy of a system at a constant pressure. It is more commonly applied as DeltaH, which is the change in both the energy of the system and the volume of its contents. Because in most systems there is a chance for outside interference that may allow for the escape of heat energy, the best method for observing this principle is with the use of a calorimeter. The device replicates a closed system free from any outside influence or alteration that keeps all of the energy constant within it in order to observe the energy transfer in certain reactions.
The easiest way to calculate the change in Enthalpy of a system is to use the specific heat of its components to calculate how they should react under certain conditions of mass and temperature. Specific heat by definition is the amount of heat per gram that is required to raise the temperature of a substance by 1 degree C. However, in this lab we are attempting to find the
Specific Heat (C) of a certain metal; copper. The reason copper is being used is due to its high levels of heat conductivity giving it a lower specific heat than most metals, as well as the fact that, unlike other metals, copper does not react with water.
In a closed system all heat is contained within the substances that make up the system. In this particular experiment those two substances are copper and water. In a normal uncontrolled experiment we would not be able to say that 100% of the heat and energy that is lost by the
copper will be transferred over to the water, but we have used not just a calorimeter to replicate a closed system, but an online calorimeter which makes the system completely simulated and controlled. In this circumstance we can say that the Enthalpy of the copper will be the same as the enthalpy of water, which will equate to the formula H
=H
. Another formula for H is
Cu
H2O
Mass (m) x The change in Temperature (aT) x Specific Heat (C) which means that mC aT=mC aT. By observing simulated reactions the textbook value for the specific heat of
Cu
H2O copper can be easily found with this formula.
The focused problem question for this experiment was “What is the specific heat of copper?” Based on the limited variable options for the virtual lab, I chose to select the mass of copper as my independent variable, because I can manipulate it easily with the provided slide adjuster. I chose to select 25.00 g, 50.00 g, 75.00 g, 100.00 g, and 120.00 g as my independent variable trails the maximum adjustment was 120.00 g, and a difference of about 25.00 g between the samples would allow for the display of a significant correlation between the mass of copper and the final temperature of the system, my dependent variable, based on the limited virtual calorimeter, which only allows me to determine the final temperature of the calorimeter after the manipulation of the mass and initial temperature of both water and copper.
It is obvious that copper has a fairly high conductivity level, because consumers use this
element for the bottom of cooking pans, because it heats up easily. This is related to the specific heat capacity of copper because they are indirect inverse properties, essentially. Because coppers heats and cools easily, it does not store energy well, unlike water. This is because copper has freely moving electrons, that pass electricity easily between each other, unlike densely packed atoms, that cannot transfer electricity well because essentially they have no place to move. As a
result of these properties, it takes very little heat to make the temperature of copper increase.
Based on this research, I hypothesize that Copper will have a significantly low heat capacity.
Controlled Variables:
Why it must be