HC2 Energy and Phase Change Name Kamalpreet Kaur When energy is added to, or rem
ID: 717184 • Letter: H
Question
HC2 Energy and Phase Change Name Kamalpreet Kaur When energy is added to, or removed from a system, the total energy of the system changes. For this investigation you will simulate sweating by wetting a finger, and then considering the energy changes that accompany this process Procedure: Be sure your hands are clean and dry. Wet one finger and then wave your hand in the ai. Observations Do you feel any difference between the wet finger and the others? If so, what is the difference? jes it is Colde Analysis 1. What do you think caused your wet finger to feel different? Do you think energy is involved in this process? Explain why you think so. It couol 've veen due to a phaJe chanoye onm 2. From what substance does energy leave? What is your evidence? 3. To what substance does the energy go? What is your evidence? How should the quantity of energy leaving, and the quantity of energy going, compare to each other? (greater than, less than, equal to) Why? (And why is should important here?) 4. 5. Consider the energy change in your finger. If the energy change, AE, is defined as Etal-Eal what is the sign of the energy change in your finger? How do you know?Explanation / Answer
Here you go:
1) Wet finger feels different since it is colder than dry fingers. This energy change is due to the vapouring of the liwuil from finger by absorbing latent heat from our body.. that's why we feel cold.
2)Energy is leaving here from our body. Evidence is our feeling of the cold on that particular finger. This is due to the latent heat used from our body.
3) To the system that is in the atmosphere the energy is transferred. Evidence is that the liquid vapourizes and goes to the atmosphere.
4) The leaving energy and the energy of going is equal to each other since there must be a equlibequil between the system and the atmosphere according to the thermodynamic laws.
5) E(initial) is more than E(final) since the dry finger is hot and when it comes in contact with wetting liquid the finger gets colder thus temperature decreases that is the energy also.. And the process is exothermic. Thus E = E(final) - E(initial) = -ve sign..
I hope it helps!!
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