Chemistry A : Heat Transfer / Specific Heat Lab



Heat Transfer / Specific Heat Lab

Name _______________________________ Date________________ Hour ________

Purpose: To experimentally measure heat transfer from a system and the specific heat of a metal.

Materials : * thermometer * calorimeter * beaker (250ml) * hot plate

* metal sample * tongs * balance

Equations:

* The equation to measure heat transfer is : Q = m * C * ΔT

Q = heat transfer in Joules (J) m = mass of substance in grams

C = specific heat of substance (J/g⁰C) ΔT = change in temperature (⁰C)

* The equation to find specific heat is : C = Q_____

m*ΔT

Procedure :

1) Obtain a metal sample and use a balance to find its mass in grams. Record this in the data table below.

2) Measure the mass of the calorimeter cup. Fill the calorimeter cup with a volume of cool water (about 100 ml) which is sufficient to cover your metal sample. Find the mass of the cup with the water. Use this to calculate the mass of the cool water.

3) Use a thermometer to find the temperature of this cool water. Record this in the data table below as initial temperature.

4) Fill a 250 ml beaker about half full with water and using a hot plate bring the water to a boil. When the water is close to boiling add the metal sample.

5) Boil the metal sample for about 3-5 minutes. This will bring the temperature of the metal to about 100⁰C. Use a thermometer to measure the actual temperature of the boiling water (which may not be exactly 100⁰C), and use this value to be the initial temperature of the hot metal.

6) Use tongs to transfer the hot metal from the beaker to your calorimeter. Gently stir and swirl the calorimeter and allow the hot metal to heat up the water. Record the temperature of the water in your calorimeter at its highest point.

7) Use the equations and instructions below to find the amount of heat transferred from the hot metal to the water, and then the specific heat of the metal.

8) Compare your answer for the specific heat of the metal to the actual value, and calculate your % error.

Data Table :

Mass of metal = _________ g

Mass of calorimeter cup = ___________ g

Mass of calorimeter cup and cool water = ___________ g

Mass of cool water in calorimeter = ______________ g

Initial temperature of cool water in calorimeter = ________ ⁰C

Temperature of water boiling with the metal = __________ ⁰C

Final temperature of cool water after hot metal added = ________ ⁰C

Change in water temperature in calorimeter caused by hot metal = ________ ⁰C

Change in metal temperature after being placed into cool water = __________ ⁰C

Calculations:

1) Find the heat transferred from the hot metal to the water in the calorimeter. Show work!

Q = m x C x ΔT m = mass of water in calorimeter

C = 4.18 J/g⁰C

ΔT = change of temp of water

Q = ________________ J

2) Find the specific heat of your metal by using the specific heat formula.

Answer this first, then do your calculation: What value will you use for Q? Why?

Cmetal = _________ J/g⁰C

3) Find the accepted value for specific heat from the teacher.

True value for ________________ is _______________ .

4) Find your percent error by : experimental value - accepted value x 100

accepted value

Questions

1. Calculate the amount of heat required to raise the temperature of 78.2g of water from 10(C to 35(C. (For the specific heat of water, use C = 4.18 J/g⁰C)

2. Calculate the specific heat for a 102g sample that requires 1430J to raise the temperature from 8.7(C to 12.5(C. (You may answer in units of J/g⁰C)

3. You have 56.7 grams of a metal that raises the temperature of 213 g of cold water in a calorimeter cup by 1.5⁰C. The metal had a temperature change of 73⁰C when it is put into the cold water. Find the specific heat capacity of the metal. (For the specific heat of water, use C = 4.18 J/g⁰C)

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