Latent Heat and Specific Heat Capacity

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Even though this experiment is rather simple and straight forward there were still a few limitations and errors that may have affect the end result. One such limitation can be seen in the design of the digital thermometer used. The thermometer only displayed a temperature that went to one decimal place or three significant figures. This can cause complications when substituting these values into complex equations that produce large numbers by generating an error after the 3rd significant figure. Another limitation in this experiment is that of time. The limited time period given to perform this experiment meant that it could only be completed once. Therefore resulting in a single value that, without the corroboration of multiple results, could not be considered to be free of abnormalities.

Conclusion

Overall the aim of the experiment is deemed to be achieved, with the result proving that the Latent heat of fusion of ice was found successfully, to a degree. When considering the measurement limitations that accompanied this experiment it is significant that a value so close to the actual Latent Heat of Fusion of ice was found. With all limitations and result deviations considered the experiment is deemed to be a success.

Part B – Specific Heat Capacity

Aim

To identify solids by measurement of specific heats.

Introduction

When energy is applied to a substance in the form of heat the temperature of that substance will rise. The efficiency in which the substance can accept and amass the heat is known as its specific heat capacity. More definitely though the specific heat capacity of a substance is defined as being “The quantity of heat needed to raise the temperature per unit mass of a substance by 1 Kelvin.” This can be calculated by using the following formula: [pic 30]

[pic 31]

[pic 32][pic 33][pic 34][pic 35]

In this experiment a process known as the ‘method of mixtures’ was used to determine the specific heat capacity of the unknown materials. This involves heating up a substance to a certain temperature then putting it in contact with another substance in a controlled environment and recording the temperature in which they reach equilibrium. In this case the two substances were an unknown metal and water, the controlled environment was a copper calorimeter and the metal was heated to 100°C. Once equilibrium was achieved and the temperature recorded the specific heat of that substance could be found by using the following formula:

[pic 36]

[pic 37]

[pic 38][pic 39][pic 40][pic 41][pic 42][pic 43][pic 44][pic 45]

It is important to note that heat, J, is a measure of the thermal energy of the material, whereas temperature, °C, is a measure of the heat content of the material.

Experimental Method

- The Calorimeter, Stirrer and Lid were weighed together and there total mass recorded. The calorimeter was filled half-way with water and weighed again. The masses were subtracted to find the mass of the water.

- The temperature of the calorimeter and water were recorded.[pic 46]

- One of the samples of metal was weighed and then immersed into continuously boiling water.

- Using tongs the sample of metal was then placed into the calorimeter. The water was continuously stirred and the maximum temperature recorded.

- Steps 1-4 were repeated for the other two samples of metal, using fresh water each time.[pic 47]

- The specific heat capacity, , was then calculated using equation 5 (see above). [pic 48]

Results

1

2

3

Mass of Wooden Lid (g)

20.3

20.3

20.3

Mass of Calorimeter, Stirrer and Lid (g)

132.1

132.1

132.1

Mass of Calorimeter and Stirrer (g)

75.4

75.4

75.4

Mass of Calorimeter, Stirrer, Lid and Water (g)

196.3

203.7

203.7

Mass of Water (g)

64.2

71.6

71.6

Temperature of the Calorimeter and Water (°C)

25.8

25.5

27.1

Mass of Material (g)

32.9

17.1

20.3

Max Temp of Water and Calorimeter (°C)

29.0

27.4

28.7

Specific Heat Capacity of the Material [pic 49]

383.6

496.8

357.5

Material

Copper

Stainless Steel

Brass

Table 3: Specific Heat Capacity

Data Analysis

Material 1:

[pic 50][pic 51][pic 52]

There