SPECIFIC HEAT OF A METAL
PURPOSE: The purpose of this experiment is to determine the specific heat of certain metals using the method of mixtures. PROCEDURE: 1. Weigh the first metal sample (Aluminum) and record its mass (ms). 2. Fill the boiler about half full of water and suspend the metal sample in it. Place the thermometer in the boiler and start the water heating while the calorimeter is being prepared. 3. Weight the inner Aluminum cup of the calorimeter when it is empty and record its mass (mc). Fill the cup about one-third full of water at a temperature about 3-5 C ° below room temperature and measure its mass. (mc+w) 4. When the water has been boiling a few minutes, record the temperature of the hot water (T1). 5. Stir the water in the calorimeter and record its temperature (T2). 6. Carefully (but quickly) remove the hot metal sample, shake or blot it to remove any clinging water drops, and place it in the calorimeter. Stir the calorimeter contents, and record the HIGHEST temperature reached (Tf). 7. Repeat with a different metal (not Aluminum). CALCULATIONS: Calculate the specific heat of Aluminum, and use this value to calculate the specific heat of the second metal. EQUATIONS: Since there is no heat gained or lost in the system:
ms c Al T f T1 mc c Al T f T2 mw c w T f T2 0
which solves to:
mw cw (T f T2 ) ms (T f T1 ) mc (T f T2 )
for the first part (Aluminum).
mw cw (T f T2 ) mc c Al (T f T2 ) ms (T f T1 )
for the second metal
QUESTIONS: 1. To which measurement do you attribute the greatest part of your error? 2. If several drops of water had been carried on the metal piece when it was placed in the calorimeter, would this raise or lower the experimental value for specific heat?
Mass of sample (ms), grams
Mass of cup (mc), grams
Mass of cup + water (mc+w), grams
Mass of water in cup (mc+w - mc ), grams T1 = T2 = Temperatures º C Tf = T1 = T2 = Tf =
Specific heat, experimental cal/(g ºC° )
* Specific heat, accepted value cal/(g ºC° ),