Easy Physics Step-by-Step

Author:Jonathan Wolf
Language: eng
Format: epub
ISBN: 9780071805926
Publisher: McGraw-Hill Education

Figure 12.1 Graph of energy vs. temperature

Problem For the graph shown in Figure 12.1, find:

a. The melting point

b. The boiling point

c. The specific heat as a solid

d. The specific heat as a liquid

e. The specific heat as a gas

f. The heat of fusion

g. The heat of vaporization

Solution

Step 1. The graph can be analyzed for many of the key concepts just discussed. If we know that the substance begins in the solid state at 0°C, then (a) the melting point is seen as 50°C (this is where the temperature is not changing as the material changes from a solid to a liquid) and (b) the boiling point is observed to be equal to 200°C.

Step 2. The specific heat of the substance as (c) a solid can be obtained using the fact that 20 joules of heat are used to raise the temperature of the material from 0°C to 50°C. Hence c(solid) = ΔQ/mΔT = (20 J)/(20 g)(50°C) = 0.02 J/g · °C

The specific heat of the substance as (d) a liquid and (e) a gas can be found by a similar analysis:

c(liquid) = (100 J)/(20 g)(150°C) = 0.033 J/g · °C

The specific heat of the substance as a gas can also be found:

c(gas) = (100 J)/(20 g)(100°C) = 0.05 J/g · °C

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.