* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Specific Heat of a Metal
Survey
Document related concepts
Water heating wikipedia , lookup
Hypothermia wikipedia , lookup
Dynamic insulation wikipedia , lookup
Heat exchanger wikipedia , lookup
Cogeneration wikipedia , lookup
Solar water heating wikipedia , lookup
Intercooler wikipedia , lookup
Solar air conditioning wikipedia , lookup
R-value (insulation) wikipedia , lookup
Copper in heat exchangers wikipedia , lookup
Heat equation wikipedia , lookup
Thermoregulation wikipedia , lookup
Transcript
Specific Heat of a Metal Honors Chemistry Laboratory Activity Chemists identify substances on the basis of their chemical and physical properties. One physical property of a substance is the amount of energy it will absorb per unit of mass. This property can be measured quite accurately and is called specific heat (Cp). Specific heat is the amount of energy, measured in joules (or calories), needed to raise the temperature of one gram of a substance one Celsius degree. Often applied to metallic elements, specific heat can be used as a basis for comparing energy absorption and transfer. To measure specific heat in the laboratory, a calorimeter of some kind must be used. A calorimeter is a well-insulated container used in measuring energy changes. The calorimeter is insulated to reduce the loss or gain of energy to or from the surroundings. Energy always flows from an object at a higher temperature to an object at a lower temperature. The heat gained by the cooler substance equals the heat lost by the warmer substance, if we assume no loss of heat to the surround environment. Heat Lost = Heat Gained In this experiment you will determine the specific heat of a metal sample. The metal sample will be heated to a high temperature than placed into a calorimeter containing a known quantity of water at a lower temperature. Having measured the mass of the water in the calorimeter, the temperature change of the water ( T), and knowing the specific heat of water (4.184 J/g*oC), the heat gained by the water (lost by the metal) can be calculated as follows: Heat gained by water (Q) = mass of water (g) x T (oC) x specific heat of water (J/g*oC) The specific heat of the metal can now be calculated: Specific heat of metal (Cp) = Heat gained by water (J) Mass of water (g) x T of metal (oC) Objectives: In this experiment, you will Measure the mass and temperature of water in a calorimeter Heat a metal sample of known mass to a specific temperature Calculate the change in water temperature caused by adding the hot metal sample Calculate the specific heat of the metal using your mass and temperature data Procedure and Data 1. Measure the mass of the empty foam cup ___________ g 2. Measure the mass of the foam cup and water __________ g 3. 4. 5. 6. 7. Measure the temperature of the water in the foam cup _________oC Record the temperature of the container holding metal cylinder ___________oC Record the final temperature of the cup/water/cylinder system ___________oC Dry the cooled cylinder and measure the mass of the cylinder __________ g Describe cylinder’s appearance and “feel”. YOUR ASSIGNMENT *Analysis, Conclusions and Further Investigations are to be completed on separate piece(s) of paper, either neatly handwritten (calculations may be offered in pencil but body of text should be in dark ink) or typed (calculations may be neatly hand written). Assignment needs to have a proper heading and the name(s) of partners. No group should be larger than three (2 preferred) and there should be no groups with duplicate data. Analysis 1. Prepare a table for your data, include materials, masses, temperature and heat gained by water and change in temperature and observations made about the appearance and “feel” of cylinder. 2. Calculate the heat gained by the water (lost by the metal) in the calorimeter using the equation in the introduced in chapter and lab. List known variable values, equation to be used…circle answers to calculations. This calculation answer along with change in temperature should be included on data table. Remember to name Data table, ex. Table 1. 3. Calculate the specific heat of the metal using the answers from number 2 and equation given in the introduction. Conclusions 1. What physical properties, other than specific heat, could you use to help you identify the sample used in the experiment? 2. Why is water an excellent material to use in a calorimeter? Try to list, at least, two. 3. Given that the specific heat of Copper is 0.386 J/g*oC, Iron is 0.448 J/g*oC, Aluminum is 0.900 J/g*oC , lead is 0.138 J/g*oC, Carbon (graphite) 0.71 J/g*oC and brass is 0.38 J/g*oC can you identify your metal, take into consideration appearance and apparent density when holding cylinder. Further Investigations: 1. Determine the percent error of your experimentally determined specific heat to that of the given (literature value). Show formula used and calculation set up. Circle answer. Then list possible reasons for error from your laboratory experience. 2. Calculate the specific heat of a metallic element if 314 joules of energy are needed to raise the temperature of a 50.0 g sample from 25.0oC to 50.0oC.