14+Heat

toc

Notes:
The formula for linear expansion is: == the Alpha is a constant for the particular substance in the problem. It is a constant. For Aluminum its 2.4 x 10 -5 /C o The change in length equals the coefficient of linear expansion times the original length times the change in temperature.



Videos:
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Heat and Thermodynamics Videos
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Lab:
Partner A & B: Do the lab on page 392-97, Specific Heat Capacity. Each of you will get a different metal to determine the specific heat of. Use the CBL Procedure (Don't forget to do the Analysis and Interpretation on page 397) Write a paragraph that explains what you learned from the lab.

**Make sure you look at the video of the graph mentioned in the discussions**.

 * re: 10 Heat**

[|amr3363] Jan 21, 2010 7:12 am Heat was a fairly easy chapter for me because of thermochemistry in Chemistry II. The graph that you drew for me at the beginning of the chapter was the most helpful resource. I took all the graphs and tables out of the book and copied them down on a sheet of paper and put them in a page protector so I would have all of the conversions right close to me. I overthought a lot of the questions, and that is why I got some of them wrong as many times as I did. I took extra steps. I also had trouble converting some of the units, but the mistakes were just careless. In the lab, the water with the Aluminum did not ever become a constant heat, so the specific heat of Aluminum probably wasn't correct since I did not have very accurate data. I did the lab twice, though, and still did not get the predicted results. I had the most trouble with trying to figure out which was gaining heat and which was losing heat. Chapter 10 in the book has all the formulas needed for this chapter, as well as the necessary graphs. Overall, the concept of this chapter was fairly easy to understand. Ashley Rentz

[|abbycatheryn] Jan 21, 2010 7:15 am The formula used the most in Q=mcT. You will use this formula on most of the problems. You will have to ask Mrs. Duncan for the formulas that go with the chart on page 376. My lab was extremely easy. Be sure to ask Mrs. Duncan if you have any problems.

[|ethanp1] Feb 8, 2010 7:10 am Chapter 10 was fairly simple mostly arranging formulas. Refer back to chapter 5 for Kinetic potential and internal energy problems. Q=mct is used alto. Remember to add latent heat to all melting ice problems and steam problems.

[|nchsclarkm] Feb 8, 2010 7:16 am At first heat is an easy chapter because there are several problems of just converting temperatures to different scales, but it is important to finish those relatively early so that you can focus on the more difficult problems. If you do not already have a temperature graph drawn by Mrs. Duncan, it is important that you get one so that you can understand what you are doing. The central idea of this chapter is that heat can be changed into another form of heat. Heat lost always equals heat gained due to the law of conservation of energy. One thing I had difficulty with was kinetic energy being transferred to internal energy. The formula for kinetic energy is Q=1/2mv^2. I found myself using that one nearly every other problem. If you're having an exceptionally hard time, remember that you are setting one heat to another kind, whether it is mc(delta)T or even mgh. Remember that a joule is measured as a kg/(m^2/s^2). Good luck, Michael Clark

[|ncmarleer] Mar 26, 2010 7:31 am I found chapter 10 heat difficult. The main formula you use is Q = mct. Look in the book to find charts on specific heat capacities and latent heat. You will have to refer back to chapter 4 for several problems. You will use the kinetic energy formula which is KE = (.5)(m)(speed)^2. You will also have a couple problems where you will use the potential energy formula which is, PE = mgh. If you are partner one you will do the aluminum water lab. To help with many of the problems Mrs. Duncan will draw and explain a graph for you. Good Luck! Marlee Rhodes

[|ncmarleer] Mar 26, 2010 7:32 am You will have to refer back to chapter 5 not chapter 4.

[|MarleeDW] Apr 8, 2010 11:24 am Get Mrs. Duncan to show you the graph for Heat.(If you took Chem 2, it's the thermo graph.) See the video. Write out all your givens and determine what is losing heat and what is gaining heat before you begin to work the problem. Some problems simply use the givens as conversion factors. Mark sure you square your velocity in the Kinetic Energy formula. If you don't you will miss the problem. Make sure your answer is in the right units and the two beakers you need for the lab are in the closet connecting the classroom to the lab. Enjoy:) Marlee Williams

[|nchsdowdyk] Apr 15, 2010 7:00 am -after you get Mrs. Duncan to show you the graph be sure to keep up with it -always remember that mc(delta)t equals the same of the other substance -be sure to know how to do your algebra to find the missing numbers -you will have to find the table in the book that tells the specific heat of substances, specific heat in a formula is C -remember that you have to add the joules of the different stages together, like when ice is melting you have to get the energy of it melting, rising in heat, changing to steam, and rising again -your change in temperature, (delta T), will always be positive so when you put it in a problem be sure to put Ti and Tf in the correct positions in the equation -anytime you have change in energy it is always joules (J) find the components of J in the very back of the book have fun, Katie Dowdy