Project Report
MonsterDrift
calorimeter_presentation_2.pptxCALORIMETER: Latent Heat of Fusion of Ice
Institution:
Course:
Project: Calorimeter
Members: 1
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Calorimeter: Latent Heat of Fusion of Ice Introduction
A calorimeter is a device that is used in measuring the quantity of heat transferred to or from an object.
Therefore, it becomes possible to determine the latent heat and specific heat of different substances and materials.
It is based on the principle that water will change its temperature when it gains or loses energy
The quantity of energy gained or lost by water is given by the equation: Q = mwater•Cwater•ΔTwater
Where specific heat, Cwater is 4.18 J/g/°C,
mwater mass of water and
ΔTwater =Final temperature-Initial temperature.
The main assumption of calorimetry is that the energy gained or lost by the water is equal to the energy lost or gained by the object or substance under study. Qice = - Qsurroundings = -Qcalorimeter.
The main purpose this project is to find the heat of fusion of ice using a simple calorimeter.
Calorimeter: Latent Heat of Fusion of Ice
Introduction
A calorimeter is a device that is used in measuring the quantity of heat transferred to or from an object. Therefore, it becomes possible to determine the latent heat and specific heat of different substances and materials. It is based on the principle that water will change its temperature when it gains or loses energy. The quantity of energy gained or lost by water is given by the equation:
Q = mwater•Cwater•ΔTwater
Where specific heat, Cwater is 4.18 J/g/°C, mwater mass of water and ΔTwater =Final temperature-Initial temperature.
The main assumption of calorimetry is that the energy gained or lost by the water is equal to the energy lost or gained by the object or substance under study. Qice = - Qsurroundings = -Qcalorimeter. The main purpose this project is to find the heat of fusion of ice using a simple calorimeter.
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Apparatus
The apparatus and materials used in this project include:
Calorimeter
Double-pan balance
Container for water
Crushed ice cubes
Schematic diagram of the calorimeter
The apparatus and materials used in this project include:
Calorimeter
Double-pan balance
Container for water
Crushed ice
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Parts of the Calorimeter
Outside container
This contains traps a layer of air between it and inside container that acts as an insulator
Inside container
It holds the content, water. Acts as calorimeter cell. It has a lid with a hole is drilled for inserting stirrer and thermometer
Thermometer
It is used measure temperature change
c
Parts of calorimeter cont’d
Stirrer
The stirrer is used to stir the mixtures and ensure uniform distribution of heat
Method
A small amount of ice is placed in a calorimeter containing water. Determining the masses of the ice, the water, and the calorimeter, and the resulting temperature change after the ice melts, the latent heat of fusion of ice is found.
The following steps describes the procedure to follow:
Measure the mass of the empty calorimeter with a balance. Record on a data table.
Pour cold water into the calorimeter, inner container, until it is one third full. Find the total mass of the calorimeter and water. Record mass on data table.
Put the lid on the calorimeter and push a thermometer through the slit in the lid.
Repeat steps one, two and three, crashed ice cubes.
Pour the ice cubes into the water in the calorimeter and close lid.
Push the thermometer through the hole in the lid and observe the temperature of the mixed water. Once the temperature stops changing, record in data chart.
Repeat the experiment twice with different masses of water.
Complete calculations to find the total mass of melted ice plus cold water. Calculate the temperature change of cold water after mixing.
Method cont’d
Using this information, calculate the heat energy of the mixed water by using the following equation:
Q = mC∆T
Find the latent heat of fusion of ice using the following equations:
Heat lost = Heat gained
Heat needed to melt ice, Q = MLf
mwCw (Tw - Tf) = MiceLf
Observational Data and Analysis
| Description | Trial 1 | Trial 2 |
| 1. Mass of Calorimeter (g) | 400 | 400 |
| 2. Mass of Calorimeter + Water (g) | 500 | 550 |
| 3. Mass water mw (g) | 100 | 150 |
| 4. Mass of ice cubes mice (g) | 21 | 30.5 |
| 5. Tice | -42.6 | -42.8 |
| 7. Tw (°C) | 22.3 | 24.4 |
| 8. Tf (°C) | 5.9 | 8.4 |
| 9. Heat lost, cool water | -6855.2J | -10032J |
| 11. Heat gained, ice | 1655.2J | 10032J |
| 12. Lfusion | 326J/g | 329J/g |
| 13. Average Lfusion | 327.5J/g | |
| 14. % error | 2.5% |
Graphical Analysis
Trial 1 data
Trial 1 graph
| Cooling Water Mixture | |
| Trial 1 | |
| Temperature (0C) | Time (Min) |
| 22.3 | 0 |
| 18.2 | 5 |
| 15 | 10 |
| 13.6 | 15 |
| 9.1 | 20 |
| 6 | 25 |
| 5.9 | 30 |
cooling water mixture: T 1
v 0 5 10 15 20 25 30 22.3 18.2 15 13.6 9.1 6 5.9
Time (min)
Temperature (0C)
Graphical Analysis
Trial 2 data
Trial 2 graph
| Cooling Water Mixture | |
| Trial 2 | |
| Temperature (0C) | Time (Min) |
| 24.4 | 0 |
| 19.3 | 5 |
| 16.1 | 10 |
| 12.4 | 15 |
| 9.7 | 20 |
| 8.8 | 25 |
| 8.4 | 30 |
Cooling Water Mixture: T 2
Cooling Water Mixture 0 5 10 15 20 25 30 24.4 19.3 16.100000000000001 12.4 9.6999999999999993 8.8000000000000007 8.4
Time (Min)
Temperature (0C)
Discussion
From the observed data in the above table, and using the equations provided, the latent heat of fusion of ice is calculated as follows:
Trial 1:
Heat lost by water = Heat gained by ice = [100*4.18*(5.9-22.3)]= 6855.2J
Trial 2:
Heat lost by water = Heat gained by ice = [150*4.18*(8.4-24.4)]= 10032J
Average Lf= (326.1+329)/2=1327.5J/g
Percentage error=
Discussion cont’d
According to the results obtained, there is a minimal error of 2.5% meaning that we have accomplished the project objective.
It is now clear that that when determining the specific heat of fusion of ice using a calorimeter, the assumption holds that the energy gained by the ice when melting is equal to the energy lost by the surrounding water. It is assumed that there is a heat exchange between the ice and the water in the inner container and that no other objects are involved in the heat exchanged.
Therefore, the first law of thermodynamics is proved, that states energy is always conserved, it cannot be created or destroyed.
Also, water tends to have different energy requirements from one state to another as shown below:
Errors/discrepancies
The heat of fusion of ice calculated had an error of only a 2.5%.
One possible source of error for this lab was the containers that were used as a calorimeter.
The lid hide wide opening and heat could have been lost to the surroundings or heat could have entered from the top.
Another possible source of error could have been in measuring the volume of water used in the calorimeter. Since the measurements of volume using the graduated cylinder have one estimated number, the estimated number could have been off resulting in an incorrect volume.
The temperature readings were taken using a thermometer that could possibly have factory errors thus affecting the results.
Another possible source of error could have come the stirrer which was a metal spoon and could have conducted heat into or from water affecting the results.
Overall, the project work went well with no major problems and a reasonable heat of fusion of ice was found, so it was a success.
Conclusion
A calorimeter is a useful is useful in determining the specific heat capacities and heat of fusion of substances.
In order to attain best results it is important to minimize heat loss or heat gain from the environment.
The basics of first law of thermodynamics, on conservation of energy facilitates the calculations as all factors are considered and or included.
The project has concluded the some of the principles of thermodynamics excellently.
References
Helrich, C. S. (2009). Modern thermodynamics with statistical mechanics. Berlin: Springer.
Kondepudi, D. (2008). Introduction to modern thermodynamics. Chichester, England: Wiley.
White, W. P. (1998). The modern calorimeter. New York: The Chemical Catalog Company, Inc.
