Chemistry Name

Lab 16 (Finding the Specific Heat Capacity of Copper)

Pre-Lab 16: This example contains data similar to what you will collect in the lab.

Calculate the specific heat of an unknown metal when 250 g of the metal is cooled from 90.0°C to 28.0°C when added to 133 g of water whose temperature went form 24.0 °C to 28.0 °C.

Use the examples from your notes to solve the following problems.

List knowns and unknown, equation, substitution, answer with units. Draw a box around each final answer.

(5 points each)

  1. Calculate the energy required to raise the temperature of 285.4 g of water by 24.0 °C.
  1. Calculate the specific heat (C) of an unknown metal when 253.95 g of the metal is cooled from 70.0 °C to 15.0 °C by losing 6,425 Joules of energy.

Chemistry

Lab 16 (Finding the Specific Heat Capacity of Copper)

Purpose: Determine the specific heat capacity of copper shot and compare the experimental value to the accepted value of 0.387 J/g•°C.

Materials:

Apron (optional)

Goggles

Ring stand

Thermometer clamp

Thermometers (2)

Styrofoam cup

Beaker (400 mL)

Beaker (800 mL)

Plastic cup (small)

Copper metal shot

Hot plate

Test tube (Large)

Evaporating dish used as a weighing tray

Stirring rod (glass)

Procedures:

  1. Put on your safety goggles.
  2. Fill the 800 mL with about 600 mL to 700 mL of tap water and place the beaker on the hot plate. Make sure the hot plate is plugged into an outlet and the power is on with the heat setting turned to its maximum position.
  3. Place the evaporating dish on the electronic balance and rezero the balance by pressing the “On” or “Tare” button. The balance should now read 0.00 g with the evaporating dish on it. Add 110 to 125 g of copper shot to the dish. Record the exact mass of the copper shot as mCu in your data table.
  4. Place one of your thermometers in the large test tube and pour the copper shot you just massed into the test tube so the shot surrounds the thermometer. Make sure no copper shot is spilled in this process otherwise you will need to repeat step #3. SAFETY NOTE: Do NOT try to jam the thermometer into the copper shot as this may break the thermometer.
  5. Place the large test tube, copper shot, and thermometer set-up into the water that is being heated on the hot plate.
  6. Place the Styrofoam cup on the electronic balance and rezero the balance by pressing the “On” or “Tare” button. The balance should now read 0.00 g with the Styrofoam cup on it. Fill the Styrofoam cup about half full of tap water and place it back on the electronic balance. Record the exact mass of the water as mwater in your data table.
  7. Place the second thermometer in the thermometer clamp and attach it to the ring stand. Lower the thermometer into the water in the Styrofoam cup. Make sure the thermometer bulb is at about 2 cm off the bottom. Record the initial temperature of the water as Ti (water).
  8. Continue heating the large test tube with the copper shot until the temperature is 90.0°C or higher.
  9. Prepare to transfer the shot to the water by tearing off some paper towel and make a hot pad for the large test tube. Also, place your stirring rod into the water so you will be ready to stir the mixture.
  10. Record the initial temperature of the hot copper in your data table as Ti(Cu). Remove the thermometer from the large test tube with copper shot and using the paper towel as a hot pad, quickly transfer the copper shot to the water in the Styrofoam cup. Immediately stir the mixture to make sure the heat is transferred evenly to the water and no metal is touching the bulb of the thermometer. Watch the temperature on the thermometer in the Styrofoam cup until it stays constant. Record this temperature as the final temperature for the water and the copper metal shot represented as Tf (water) and Tf (Cu).
  11. Clean up the mixture of water and copper shot as directed by your teacher. Please do not dump down the sink, as the copper shot will clog the drains.
  12. Make sure that all equipment is returned to its proper place clean and dry.


Lab 16 (Finding the Specific Heat Capacity of Copper) Name

Data and Observations:

Direct Observations:

Copper metal shot / Water
mCu = / mwater =
Ti (Cu) = / Ti (water) =
Tf (Cu) = / Tf (water) =

Summary of observations and calculations:

Substance / mass, m
(g) / Initial Temp. (°C) / Final
Temp. (°C) / DT
(°C) / Specific Heat, C
(J/g•°C) / Heat transferred, DH
(J)
Copper shot
Water / 4.184

Calculations and Graphs: Show the equation used for each calculation:

i.e. DT(Cu) = Tf (Cu) - Ti (Cu) or DH(water) = m (water) x C (water) x DT(water

Calculate the change in temperature for the copper metal shot.

Calculate the change in temperature for the water.

Calculate the change in enthalpy, DH, for the water.

Determine the heat lost by the copper metal shot to the water.

Calculate the specific heat capacity of the copper metal shot.

Calculate the percent error using 0.387 J/g•°C as the accepted specific heat capacity of copper metal.

Conclusion: (Use complete sentences to describe your conclusion, whether or not you fulfilled the purpose of the lab, and how your results compared with the accepted data.)

Post-Lab Questions:

1.  A student spills some copper metal shot during the transfer into the test tube and decides not to mass the sample again. Will this mistake cause the specific heat of copper to be higher or lower than expected? Explain.

2.  The transfer of the hot copper shot to the water takes over a minute for a student to complete. How will this loss of heat to the room affect their final result for the specific heat of copper? Will it be higher or lower than expected? Explain.