Page 168 - Chemistry eBook
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4 12 20. 28 36 44 52 60.
Heat Added (kJ)
57 Describe what happens toSbaomthptlhe pRotegnteianltesneQrguy eansdtitohensaverage kinetic energy of
the molecules in the H2O sample during interval AB. [1]
58 Using the graph, determine the total amount of heat added to the sample during
interval CD. [1]
59 Explain, in terms of heat of fusion and heat of vaporization, why the heat added during
interval DE is greater than the heat added during interval BC for this sample of water. [1]
June 2013 #58
Answer
8 kJ. If you wrote 7 kJ or 9 kJ, you would get the answer right. We need to figure out how much heat was added from point C to point D.
P.S./Chem.–June ’13 [9]
a. Let’s figure out how much heat there was at point C and point D.
[OVER]
The interval of each box is 4 kJ. (There is an interval of 8 for 2 boxes. So 8÷2=4.)
To make this problem simpler, label each unmarked line by adding 4 to the number of the previous line.
b. Then find the heat added for points C and D. Point C: 7 kJ Point D: 15 kJ
c. Subtract the two values to find the answer: 15 kJ – 7 kJ = 8 kJ
167 © UNIT 5: MATTER
