Name: ______Date: ______Period: ______

Determining the Specific Heat of a Metal

Purpose: The purpose of this lab is to determine the specific heat of a metal by adding a hot metal to water in a calorimeter and measuring the temperature change of the metal and the water. The ability of any material to retain heat energy is called that material’s heat capacity. The measure of heat capacity, or the quantity of heat needed to raise the temperature of one gram of a substance by one degree Celsius, is termed specific heat. The specific heat can be calculated from the Law of Conservation of Energy which yields the equation: Heat Lost by the Metal = Heat Gained by the Water or mmCpm∆tm = -mwCpw∆tw

Procedure

  1. Prepare a hot water bath by filling the beaker two-thirds full of water. Place the beaker on your hot plate and heat up the water to a very warm temperature (about 60°C-70°C). Be careful to not touch the hot water or beaker.
  1. Stack 2 Styrofoam cups, one inside the other. This set of cups will be the calorimeter. Mass the empty calorimeter on an electronic balance and record its mass in the data table.
  1. Using the graduated cylinder, measure 100.0 ml of cold tap water and pour into the Styrofoam cups. Mass the calorimeter again and record this mass in the data table below.
  1. Using the thermometer measure and record the initial temperature of the water in your Styrofoam cups in the table below.
  1. Using the electronic balance, measure the mass of your metal marble and record in the data table below.
  1. At this point your water should be hot enough so you can remove your beaker from the hot plate with the beaker tongs and carefully place your metal marbles in your hot water bath. Allow the hot water and metal to come to thermal equilibrium and then record the initial temperature of your metal in the table below.
  1. Using tongs, remove the metal sample from the hot water bath and carefully place it in your calorimeter.
  1. Place the thermometer in the calorimeter, measure the final temperature of the water metal mixture when they are in thermal equilibrium.
  1. Repeat steps 3-8 for your other metal sample.

Metal Sample A / Metal Sample B
Mass of Empty Calorimeter
Mass of Calorimeter + Cold Water
Mass of Cold Water
Mass of Metal Marble
Initial Temperature of Cold Water
Initial Temperature of Hot Metal
Final Temperature of Metal+Water
Change in Temp of Cold Water
Change in Temp of Hot Metal

Calculations:

  1. Knowing that the specific heat of water = 4.184 J/g.oC, calculate the heat gained by the water using the equation qw = mwcw∆Tw. Do this for each sample. Show your equation and substitutions!

Water from Metal Sample A TrialWater from Metal Sample B Trial

  1. Based on the Law of Conservation of Energy, how much heat was lost by the metal in each part of the lab? Watch signs!

Metal Sample A: q = ______Metal Sample B: q = ______

  1. Now, calculate the specific heat of the metal(s) using the equation: qm = -mmcm∆Tm. Show your equation and substitutions!

Metal Sample AMetal Sample B

Substance / Specific Heat (J/g°C)
Aluminum / 0.902
Steel / 0.480
Nickel / 0.444
Copper / 0.385
Zinc / 0.385
Brass / 0.380
Tin / 0.21
Lead / 0.160
  1. Using the table to the right, identify the metals you most likely had in your experiment.

Metal Sample A: ______

Metal Sample B: ______

Post-Lab Analysis-Use complete sentences!

  1. What was the point of using 2 Styrofoam cups to make your calorimeter?

Temperature Change of Metal Sample A
Specific Heat of Metal Sample A
Temperature Change of Cold Water (sample A)
Specific Heat of Water
  1. Fill in this table to the right using your data:
  2. Based on what you have filled in, analyze the information to determine whether specific heat and temperature change are directly or indirectly related. Use your data to support your answer.
  1. If a metal with a higher specific heat were used, would this raise or lower the final water temperature? Explain.

(hint: think about how this different specific heat would affect your temperature change.)

  1. If you were to use a sample of mass that was significantly larger than used in this experiment, would this raise or lower the final water temperature? Explain. (hint: think about how mass affects temperature change).
  1. On a hot summer day, you step outside barefoot. The concrete under your feet is very hot so you run over to the grass which feels cool under your feet. Which material has the higher specific heat, the grass or the concrete? Explain.
  1. An atom of aluminum has an atomic mass of 4.48x10-23g while a copper atom has a mass of 1.06x10-22 g
  2. If you were to have a sample of 60 g of each material, which sample would contain more atoms? Why?
  1. Explain how this discrepancy in the number of atoms in the sample affects the specific heat of the metal. (hint: think about what is happening to molecular motion when its temperature is raised)