<p>Experiment-6: Specific Heat of a Metal </p><p>Specific Heat is defined as the amount of heat energy required to raise the temperature of 1.00 g substance by 1 oC. Two popular units for specific heat are cal/g x oC (cal g -1 oC-1) and J/g x oC (J g -1 oC-1). Specific Heat of water is 1.00 cal g -1 oC-1</p><p>A calorie is amount of heat required to raise the temperature of 1.00 g of water by 1.00 oC.</p><p>1 cal = 4.184 Joules</p><p>1000 cal = 1 kcal</p><p>Heat energy is measured in calories or joules. The amount of heat absorbed/released depends upon the mass of sample, its specific heat, and the temperature difference. For example, calculate the amount of heat necessary to raise the temperature of 40.00 g of water from 22.0 oC to 45.0 oC:</p><p>Heat absorbed = mass of water x specific heat of water x T</p><p>= 40.00 g x 1.00 cal/g x oC x (45.0 oC - 22.0 oC) cal</p><p>= 920 cal</p><p>Metals are good conductor of heat. Therefore, metals have low specific heat values indicating the fact that metals need less heat to raise their temperatures.</p><p>In this experiment, a coffee-cup is used as the ‘Insulated Calorimeter’. Therefore, the heat lost by the hot metal sample is equal to the heat gained by the cold tap water. </p><p>Heat lost by the hot metal = Heat gained by Water </p><p>[Mass of metal sample x specific heat of the unknown metal x temperature drop] cal </p><p>= [Mass of water x specific heat of water x temperature gain] cal</p><p>All numbers are known from the experimental observations except specific heat of the unknown metal, which will be computed at the end.</p><p>Procedure:</p><p>1. Please put coffee cups and the metal samples back after you finish your experiment</p><p> because these are reusable. Review Figure 1 and 2.</p><p>2. Fill up a 600 ml or 400 ml beaker 2/3rd with regular tap water. Put this beaker on top a</p><p> hot plate. Put your unknown metal sample in a test-tube. The metal should fill-up</p><p> approximately 1/3rd of the test-tube. Clamp this test-tube using a metal utility clamp to</p><p> the Iron stand. Carefully suspend this test tube into the beaker containing water. The</p><p> test tube should not touch the bottom of the beaker. Now, turn on your hot plate.</p><p>Bring the water to a boil. Let the water boil for 10 minutes. While waiting you may do</p><p> the following steps.</p><p>3. Obtain one coffee cup. Find its mass. Record all the digits.</p><p>4. Put 40 ml tap water into this coffee cup. Find the mass of coffee cup plus water. Now,</p><p> place the coffee cup in an empty 400 ml beaker for support to avoid any spill.</p><p>5. Insert a thermometer into this water sample in the coffee cup. Hold it vertical for 3-4</p><p> minutes. Read and record the temperature of this cold-water sample. Take out this</p><p> thermometer and insert into the boiling hot water. Read and record the temperature of</p><p> boiling hot water. The temperature of the hot metal in the test tube is same as the</p><p> temperature of boiling hot water. Put this thermometer aside. Do not shake the</p><p> thermometer! Use only one thermometer throughout the experiment.</p><p>6. Carefully transfer, as demonstrated by your teacher, the hot metal into the coffee cup</p><p> containing water. Swirl the contents (water + metal) for 15 seconds. Insert the</p><p> thermometer into the (water + metal) mixture in the coffee cup. Hold it vertical for 3-4</p><p> minutes. Read and record the temperature. This is known as the Equilibrium</p><p> temperature of the mixture. </p><p>7. Shut-off the hot plate. Unplug it. Carefully throw away the hot water in the sink. Drain</p><p> out water from the coffee up. Save the metal and coffee cup for future use. 8. In this experiment, you have made three mass measurements and three temperature</p><p> measurements. Laboratory Report#6: Specific Heat of a Metal Last Name______, first name______</p><p>Date of Experiment______Instructor’s Initials______</p><p>1. Mass of an empty Styrofoam cup = …………………………….g </p><p>2. Mass of the Styrofoam cup with water =…………………………….g </p><p>3. Mass of Water in the cup (#2 - #1) =…………………………….g </p><p>4. Temperature of regular cold tap water, in the Styrofoam Cup =…………. oC (around 22.0 oC) </p><p>(Do not shake the thermometer!)</p><p>5. Temp.of hot unknown metal sample = Temp. of boiling hot water =……. oC (around 100.0 oC) </p><p>(Do not touch bottom of the beaker!)</p><p>6. Equilibrium temperature (after pouring the hot metal sample into the Styrofoam Cup containing regular cold tap water) =…….oC </p><p>7. Mass of the Styrofoam cup with regular cold tap water and Metal sample=………………….g</p><p>8. Mass of the Metal sample (#7 - #2) =…………………………….g </p><p>9. Heat gained by Water = [mass of water x specific heat of water x temperature gain] cal</p><p>= [# 3 g x 1.00 cal/g x oC x (#6-#4) oC] cal = #3 x (#6-#4) </p><p>= …………………….. cal</p><p>10. Heat lost by the hot metal = Heat gained by Water = Same value as calculated in step-9</p><p>= …………………….. cal</p><p>= [Mass of metal sample x specific heat of metal x temp. drop] cal</p><p>= [# 8 g x X cal/g x oC x (#5-#6) oC] cal</p><p>11. Specific heat of metal, X = (Heat gained by Water) / (Mass of metal sample x temperature drop)</p><p>= [(#9) / (#8 x (#5-#6)] cal/g x oC</p><p>=……………………………… cal/g x oC</p><p>Show all your work and use proper units and significant figures! 1. 50.00 g of a metal sample is heated to 100 oC and then it was dropped into 85.0 g of water at </p><p>22.0 oC. The equilibrium temperature of the mixture was found to be 25.0 oC. Calculate:</p><p>(a) Heat gained by the water</p><p>(b) Heat lost by the metal</p><p>(c) Specific heat of the metal</p><p>2. Calculate the number of calories needed to increase the temperature of 50.0 g of copper metal </p><p> from 21.0 oC to 75.0 oC. Given, the specific heat of copper is 0.382 cal/g x oC.</p><p>3. What will be the final temperature if 2000 g of copper at 95 oC loses 10 kcal of heat?</p>