Lab 3 Determining the Specific Heat of a Metal

Lab 3: Determining the Specific Heat of a Metal °C in boiling water and x Cwater x (Tfinal - Tinitial) The specific heat of the metal can now be calculated: x Cmetal x (Tfinal - Tinitial) Apparatus 500 cm3 beaker, water, hotplate, electronic balance, metal sample, coffee cup and lid (the calorimeter), tongs, clamp, data logger and temperature probe, safety goggles. Procedure 1) Fill a large beaker approximately half full of water. Place the beaker of water on the hot plate. Begin heating the water to the boiling point. 2) 3) Determine the mass of your metal sample and record in the table below. Obtain a calorimeter cup and lid. Record their mass carefully in the table. 4) Add about 1inch depth of water to the coffee cup and record the total mass. Determine the mass of water in the calorimeter cup by subtracting the mass of coffee cup and lid. 5) CAREFULLY transfer the metal to the beaker of heating water using the tongs. Boil at least 5 minutes to be sure that the temperature of the metal is 100oC. (It is assumed that the temperature of the metal is the same as the boiling water.) 6) Measure the temperature of the cold water IN THE CALORIMETER CUP and record to one decimal place. 7) After 5 minutes, CAREFULLY remove the metal from the water bath with the tongs. Immediately place the metal into the calorimeter cup so that the metal is covered by the water. Cover the calorimeter with its cover. Turn off the hot plate. 8) Carefully insert the temperature probe through the small hole in the cover. Stir very slowly, and record the highest temperature reached by the water to 1 decimal place. 9) Remove the calorimeter cover, retrieve and dry the metal. Return metal to its original place. Pour the water down the sink. Rinse and dry the calorimeter cup. 10) Repeat the entire procedure with 3 times if time permits. Lab 3: Determining the Specific Heat of a Metal Observations: Name of Metal Used _____________________ (10 points) DATA TABLE 1: MEASUREMENTS OF MASS (g) Trial 1 Trial 2 Trial 3 mass of metal \ mass of calorimeter mass of calorimeter + water mass of water DATA TABLE 2: MEASUREMENTS OF TEMPERATURE (°C) Trial 1 Final temperature of metal (same as final temp. of water) Initial temperature of metal Temp. change of metal (Tfinal - Tinitial) \ Final temperature of water (same as final temp of metal) Initial temperature of water in the calorimeter Temp. change of water (Tfinal - Tinitial) (10 points) Trial 2 Trial 3 Calculations: show all units! 1. Heat gained by water: Use equation 2 on page 1 in the introduction 2. Experimental specific heat of the metal: Use the equation 3 on page 1 in the introduction 3. Percent error = | experimental value – accepted value | x 100 accepted value 1. Calculate the heat gained by the water in each trial by using equation 2. ( 5 points) Trial 1 Trial 2 Heat gained = Heat gained = 2. Remembering that the heat gained by the water is equal to, but has the opposite sign of, the heat lost by the metal, calculate the specific heat of metal for each trial by using equations 1 and 3. (5 points) Trial 1 Trial 2 specific heat of brass = specific heat of brass = 3. Calculate the average value for the specific heat of the metal used in your experiment from your 3 trials. (3 points) Average specific heat of ___________________ = ____________________________ 4. Look up the accepted value for the specific heat of your metal from tables and record it. (3 points) Note that the accepted specific heat capacities for some of the metals can be found in your textbooks or by using ptable.com website. (Pay attention to units – they matter!) Reference Source for Known heat capacity of ________________ (name of metal). Use APA format. _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ ________________________________________________ 5. Calculate your percentage error in your experiment to find the specific heat capacity of your metal. (4 points) The percent error in your measurements may be calculated by using the equation from Table T of your reference tables. Questions 1) What is the purpose of this lab? (2 points) 2) What physical properties, other than specific heat, could you use to help you identify the metal samples? (3 points) 3) What are some sources of experimental error for this lab activity ? (5 points)