Specific Heat Lab

Group Member Names One physical property of a pure substance is the amount of heat energy it will absorb per unit of mass. This property can be measured quite accurately and is called SPECIFIC HEAT (Cp). Often applied to metallic elements, specific heat is the amount of heat needed to raise the temperature of 1 gram, 1 degree Celsius. Equation: ΔQ = m x Cp x ΔTΔQ = amount of heat lost or gained (Joules or calories)m = mass (grams)Cp = specific heat (J or (cal = change in temperature (oC)To measure the specific heat, you will use a CALORIMETER which essentially is an insulated cup filled with water that prevents the loss or gain of heat energy from the surrounding environment. The amount of heat lost by the metal as it cools down is trapped in the water within the calorimeter. As the result of trapping heat, the water warms up. You can therefore assume that the heat lost by the metal in cooling equals the heat gained by the water in warming.PURPOSE: To determine the specific heat of a metal sample.MATERIALS: thermometer Al or Pb shot Hot plate test tube styrofoam cupPROCEDURE: 1. Determine and record the mass of an empty, dry test tube. 2. Add metal shot to the pre-massed test tube until it is 1 full (less than ½). Record the mass of the test tube and metal shot.3. Clearly label your test tube and add it to the water on the hot plate.4. Once the water has begun to boil, continue heating the water and test tube for 8 full minutes. This allows the metal to achieve the same high temperature as the water bath.5. Meanwhile, obtain a Styrofoam cup and measure and record the mass carefully. The cup will serve as the calorimeter.6. Fill the cup about 3 full with tap water and re-mass.7. Measure the temperature of the water in the calorimeter and record. (CAUTION: DO NOT PLACE THE CALORIMETER NEAR THE HOT PLATE)8. After 8 minutes of boiling together, determine the temperature of the metal shot 🡪 Since it is assumed to be the same as the boiling water, record the temperature of the boiling water.***9. Place a thermometer into the calorimeter and allow the temp to stabilize in the tap water.10. Carefully remove the hot test tube and shot from the water bath. IMMEDIATELY dump the hot shot into the styrofoam cup.11. Stir the water in the styrofoam cup SLOWLY (thermometers can be broken easily), then record the highest temperature reached – FINAL METAL, WATER TEMPS.12. Decant the water and pour the metal shot onto a paper towel to dry. Return all others materials to proper storage areas. Data Metal Shot Used Mass of empty test tube Mass of metal Mass of test tube + metal Mass of styrofoam cup Mass of water Mass of styrofoam cup + water Temperature of boiling water + metal (initial) Temperature of water Temperature of water + metal 1. Find the amount of heat gained by the water (lost by the metal).Calculate to 3 sig figs using ΔH = heat gained by water m = mass water Cpwater = 4.184 J ΔT = temperature change of water. 2. Find the experimental specific heat (Cp) of your metal to 3 sig figs. Remember that the heat that was gained by the water is the same heat that was lost by the metal.ΔH = heat lost by metal m = mass metal ΔT = temp change of metal 3. The accepted specific heat of Al is .900 J 0C and the Cp of Pb is .130 J 0C. Determine the percent error of the experiment to 1 decimal. 4. Give 3 errors in the procedure that could have prevented you from getting good experimental results. (An error less than 1%) 5. Why is water an excellent material to use in a calorimeter? 6. Calculate the specific heat of metal if 50.0g of the metal needed 314J of heat energy to change its temperature from 250C to 500C.