PRACTICAL 21
To measure the specific heat of fusion of ice
VIVA VOCE
1.What is specific heat of fusion?
The specific heat of fusion is the amount of heat energy required to change 1 gram of a substance from solid to liquid at its melting point without changing its temperature.
2.Why is it important to measure the specific heat of fusion of ice?
Measuring the specific heat of fusion of ice is important for understanding thermal properties of substances, which has applications in fields like meteorology, climate science, and engineering.
3.What apparatus and materials are required for this experiment?
The experiment requires a calorimeter, a thermometer, ice, water, a balance, and a stirrer.
4.Can you explain the principle behind this experiment?
The principle is based on the conservation of energy. The heat lost by the warm water is equal to the heat gained by the melting ice plus the heat required to raise the temperature of the melted ice to the final temperature.
5.How do you ensure that the ice is at 0°C before starting the experiment?
By allowing the ice to sit in a mixture of ice and water for some time until thermal equilibrium is reached, ensuring it is at 0°C.
6.Why is it important to dry the ice before adding it to water?
To avoid adding extra water to the calorimeter, which would affect the accuracy of the heat calculations.
7.How do you calculate the amount of heat absorbed by the ice?
By using the formula Q=m⋅Lf
is the heat absorbed, m is the mass of the ice, and Lf is the specific heat of fusion.
8.What precautions should be taken to minimize heat loss during the experiment?
Use an insulated calorimeter, minimize the time the calorimeter is open, and ensure the surroundings are at a constant temperature.
9.Why do we use a calorimeter in this experiment?
A calorimeter helps to contain the system and minimize heat exchange with the surroundings, ensuring more accurate measurements.
10.How do you ensure that the mixture of water and ice is at thermal equilibrium?
By stirring the mixture continuously and allowing sufficient time for the temperature to stabilize.
11.What formula is used to calculate the specific heat of fusion of ice?
The formula is
Lf= Q/m
12.How do you determine the mass of the ice and the water used in the experiment?
The mass of the ice can be measured using a balance before adding it to the calorimeter. The mass of the water can be measured by weighing the calorimeter with water and then subtracting the weight of the empty calorimeter.
13.What is the significance of the final temperature in the experiment?
The final temperature helps in calculating the heat exchanged between the water and the ice to determine the specific heat of fusion.
14.How does the initial temperature of water affect the results?
The higher the initial temperature, the more heat is available to melt the ice, affecting the total heat calculation.
15.What could be some sources of error in this experiment?
Possible sources of error include heat loss to the environment, inaccurate temperature measurements, and the presence of impurities in the ice or water.
16.How can you improve the accuracy of your measurements?
Use a well-insulated calorimeter, ensure precise temperature measurements, dry the ice thoroughly, and use pure substances.
17.What is the latent heat of fusion of ice?
The latent heat of fusion of ice is approximately 334 J/g.
18.How does the specific heat of fusion of ice compare to that of other substances?
The specific heat of fusion of ice is relatively high compared to many other substances, indicating it requires a significant amount of energy to change from solid to liquid.
19.Why is it necessary to stir the water-ice mixture?
Stirring ensures uniform temperature distribution throughout the mixture, leading to more accurate measurements.
20.What is the theoretical value of the specific heat of fusion of ice?
The theoretical value is approximately 334 J/g.
21.How would impurities in the ice affect the results of the experiment?
Impurities could lower the melting point of the ice and change the amount of heat absorbed during melting, leading to inaccurate results.
Why is it important to calibrate the calorimeter?
Calibration accounts for any heat absorbed or lost by the calorimeter itself, ensuring more accurate measurements.
What is the role of the thermometer in this experiment?
The thermometer measures the initial and final temperatures of the water-ice mixture, which are essential for calculating the heat exchange.
Can you describe a real-world application where knowing the specific heat of fusion of ice is important?
Knowledge of the specific heat of fusion of ice is crucial in designing refrigeration systems, understanding and predicting weather patterns, and in various engineering applications related to thermal management.