Water is the most important substance on Earth. One reason for its usefulness is that it exists as a liquid over a wide range of temperatures. In its liquid range, water absorbs or releases heat directly in proportion to its change in temperature.
Consider the following data that show temperature of a 1,000 g sample of water at normal atmospheric pressure as a function of heat supplied. A kJ can simply be thought of a unit of heat.
Temperature Heat Supplied
0 oC 0 kJ
10 oC 42 kJ
30 oC 126 kJ
50 oC 209 kJ
80 oC 335 kJ
99 oC 414 kJ
100 0C 420 kJ
Based on these data, please supply the following:
1. Provide a graph of the data. Is the graph sufficiently linear to allow prediction of heat supplied versus temperature in the range of 0-100 oC?
2. If so, use Microsoft Excel to provide an equation that relates heat, y, supplied to temperature, x, in the range of 0-100 oC.
3. Are the results consistent with the expected equation, heat = (1.00 cal/g oC) * mass in grams * (final temperature - initial temperature)? Please comment.
4. Use your equation to solve for the following:
* heat supplied at 60 oC
* final temperature when 175 kJ of heat has been supplied
* initial temperature if 200 kJ of heat is added and the final temperature is 50 oC
5. Can the model supply heat/temperature data in other ranges, for example at -5 oC or at
150 oC? Explain why or why not.
Hello and thank you for posting your questions to Brainmass.
The solution is attached in two files which are identical in content but differ in format. One is an MS-Word document while ...
The solution shows how to retrieve the heat capacity of water using a linear regression of data points.
The solution includes an Excel file.