Specific Heat of Metals 1 a

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Physics

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Dec 6, 2023

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Name Anthony Cervantes Date 09/28/2023 Class PHYSICS_011 Specific Heat of Metals Purpose To compare the specific heats of water and some common metals and draw conclusions about the application of the properties. Connections to What You Already Know About in Life On a hot summer day, it is always refreshing to jump into a pool because the water is cooler than the air around you and the ground that is roasting your feet. This may seem strange since the water and ground are being heated by the same source—the sun. This evidence suggests it takes more heat to raise the temperature of some substances than others, which is true. Vocabulary Specific heat Background Heat capacity is a numerical way to express how much heat it takes to heat something up 1 degree. So an object with low heat capacity requires very little heat to heat it up, while an object with high heat capacity takes a lot of heat to change its temperature. The amount of heat required to raise the temperature of 1 g of a substance by 1 degree Celsius is called the specific heat capacity, or specific heat, of that substance. Water, for instance, has a specific heat of 4.184 J/g  C. In this experiment, you compare the specific heats of common metals and water to see how the specific heat of a substance affects how fast it changes temperature. Procedure 1. Start Virtual Physics and select Specific Heat of Metals from the list of assignments. The lab will open in the Calorimetry laboratory. 2. You will be measuring the heat capacity of Al and Stainless Steel, two common metals. Make sure to keep track of which sample you are testing by keeping accurate notes. Record the mass of Al on the balance. If it is too small to read click on the Balance area to zoom in, record the mass of Al in the Data Table below, and return to the laboratory. 3. Pick up the Al sample from the balance pan and place the sample in the oven. Click the oven door to close. The oven is set to heat to 200 C. 4. The calorimeter has been filled with 100 mL water. The density of water at 25 C is 0.998 g/mL. Use the density and volume of the water to determine the mass and record the volume and mass in the Data Table. Make certain the stirrer is On (you should be able to see the shaft rotating). Click the thermometer window to bring it to the front and click Save to begin recording data. Allow 20-30 seconds to obtain a baseline temperature of the water. pg. 1 - Specific Heat of Metals © Beyond Labz , all rights reserved
Name Anthony Cervantes Date 09/28/2023 Class PHYSICS_011 5. Click on the Oven to open it. Drag the hot aluminum sample from the oven until it snaps into place above the calorimeter and drop it in. Click the thermometer and graph windows to bring them to the front again and observe the change in temperature in the graph window until it reaches a constant value and then wait an additional 20-30 seconds. Click Stop in the thermometer window. (You can click on the clock on the wall labeled Accelerate to accelerate the time in the laboratory.) A data link will appear in the Lab Book. Click the link icon and record in the Data Table below the temperature before adding the Al and the highest temperature after adding the Al. (Remember that the water will begin to cool down after reaching the equilibrium temperature.) 6. Repeat the experiment with a Stainless Steel sample. Click the red disposal bucket to clear the lab. Click on the Stockroom to enter. Double-click the Dewar calorimeter to move it to the Stockroom counter. Click the metal sample cabinet. Open the bottom drawer (the samples are alphabetically arranged) by clicking on it, select the Steel by double-clicking and zoom out. Double-click on the Petri dish with the selected sample to move it to the Stockroom counter. Return to the laboratory. 7. Move the Petri dish with the sample to the spotlight next to the balance. Click on the Balance area to zoom and make sure the balance has been tared. Move the metal sample to the balance pan and record the mass in the Data Table. Return to the laboratory. 8. Double-click the calorimeter to move it into position in the laboratory. Click the oven to open the door. Move the metal sample from the balance pan to the oven and click to close the oven door. Click above the tens place several times on the front of the oven to change the temperature to 200 C. Fill the 100 mL graduated cylinder with water by holding it under the tap until it returns to the counter and then pour it into the calorimeter. Turn on the stirrer. Turn on the thermometer. Click on the Graph and Save buttons. Move your metal sample from the oven to the calorimeter. Follow the procedures used with Al to obtain the equilibrium temperature. Record all of your observations in the Data Table. Questions Al Stainless Steel Mass of metal (g) 7.2168 22.5664 Volume of water (mL) 100 100 Mass of water (g) 99.8 99.8 Initial temperature of water (°C) 25 25 Initial temperature of metal (°C) 200 200 Max temperature of water & metal (°C) 27.33 29.09 pg. 2 - Specific Heat of Metals © Beyond Labz , all rights reserved
Name Anthony Cervantes Date 09/28/2023 Class PHYSICS_011 Specific Heat (J/g°C) .7864 .4373 1. Determine the change in temperature of the water ( T Δ water ) for Aluminum. T water+ T final water- T Initial water+27.37-25=2.37© which is change of temperature of the water. 2. Calculate the heat ( q ) gained by the water using the following equation: q water = m water DT water C water , given C water = 4.184 J/(g C) =99.8x2.33x 4.184 =972.9223J 3. Determine the change in temperature of the Al ( Δ T Al ). TAI= T initial A1 – T final A1=200-27.37=172.63 Celsius. 4. Remembering that the heat gained by the water is equal to the heat lost by the metal (which is why the q is negative), calculate the specific heat of aluminum. q water =− q metal = m Al ΔT Al C Al which when solved for the heat capacity is: C Al = q metal ( m metal )( ΔT metal ) . Record your result in the Table. =-972.9223/7.2168 x 172.67 = -0.7808 = 0.7808J/(gc) 5. Repeat the calculation of specific heat capacity for Steel and record your result in the Data Table. =-1686.9552/22.5664 x 170.96 =0.4373 J/(gc) 6. If you have a can made of steel and one made of aluminum, describe what will happen to the temperature of the cans when you pull them out of the refrigerator. Include in your discussion connections to the specific heat of the metals. Aluminum has a greater specific heat capacity compared to steel as shown. It would mean thar aluminum would absorb heat faster than steel hence record a higher rate of change of temperature 2ith the respected time for both. Thus, aluminum will get to room temperature first. 7. Many cooking pans are made out of steel and there are also some made of aluminum. Discuss which type of pan you think would be better. Cooking pans are more efficient and effective when they are capable of absorbing heat at a faster rate. Which will then make aluminum cooking pans more viable as they absorb the heat faster compared to pg. 3 - Specific Heat of Metals © Beyond Labz , all rights reserved
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Name Anthony Cervantes Date 09/28/2023 Class PHYSICS_011 steel making aluminum cooking pans better and a overall better product when it comes to heat temperature and time. 8. When the same amount of heat is applied to both, which will heat up to a higher temperature—a given mass of water or that same total mass of water and steel together? Why? They would not get to room temperature at the same time, the water and steel would register a higher heat absorption and dissipation rate compared to the same mass of water alone. Steel being able to conduct heat faster than water would make the mixture have enhanced conductivity. But both would have different temperatures at different times due to the absorption of heat and water from that absorption. 9. Design and execute an experiment to test your hypothesis from Question 8. Write a summary of your experiment and report your results. Also observe the cooling of pure water and water and steel together and report on the differences in how they cooled. Testing the hypothesis, 110 ml of water heated and cooled and the temperature changes with time recorded. Afterwards the steel solid was put in 100 ml water in calorimeters and the mixture heated and cooled with temperature changes being recorded. The rates of change of temperature with time for both was computed for both heating and colling phases. Change in temperature for water on heating=0.9035 Change in temperature for water on cooling=0.0104 Change in temperature for water and steel on heating= 1.0876 Change in temperature for water and steel cooling= 0.009 All in all, the hypothesis was proved that the mixture recorded higher rate of temperature change for both phases and not just one so there is the results of this hypothesis. pg. 4 - Specific Heat of Metals © Beyond Labz , all rights reserved