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A bag containing 0ºC ice is much more effective in absorbing energy than one containing the same amount of 0ºC water.

a. How much heat transfer is necessary to raise the temperature of 0.800 kg of water from 0ºC to 30.0ºC?
b. How much heat transfer is required to first melt 0.800 kg of 0ºC ice and then raise its temperature?
c. Explain how your answer supports the contention that the ice is more effective.

1 Answer

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Final answer:

To heat 0.800 kg of water from 0°C to 30.0°C, 100.32 kJ is required. Melting 0.800 kg of 0°C ice and then raising its temperature takes a total of 367.52 kJ. This larger amount of energy needed affirms that ice absorbs more energy due to its heat of fusion.

Step-by-step explanation:

To determine the heat transfer necessary to raise the temperature of 0.800 kg of water from 0°C to 30.0°C, we utilize the specific heat capacity of water, which is approximately 4.18 kJ/kg°C. For part (a), the calculation is as follows:

Heat transfer = mass × specific heat capacity × temperature change

Heat transfer = 0.800 kg × 4.18 kJ/kg°C × (30.0°C - 0°C)

Heat transfer = 100.32 kJ

For part (b), we need to add the heat of fusion for ice, which is 334 kJ/kg, to the heat necessary to raise the water temperature after melting. This results in two separate calculations:

Heat to melt ice = mass × heat of fusion

Heat to melt ice = 0.800 kg × 334 kJ/kg

Heat to melt ice = 267.2 kJ

Heat to raise temperature (after melting) = mass × specific heat capacity × temperature change

Heat to raise temperature = 0.800 kg × 4.18 kJ/kg°C × 30.0°C

Heat to raise temperature = 100.32 kJ

Total heat transfer for ice = Heat to melt ice + Heat to raise temperature

Total heat transfer for ice = 267.2 kJ + 100.32 kJ

Total heat transfer for ice = 367.52 kJ

The total heat absorption by ice is significantly higher due to the energy required for the phase change. This demonstrates that 0°C ice is more effective at absorbing energy because it requires additional heat to change from solid to liquid before its temperature can increase.

User Victor Henriquez
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