Calculate the quantity of heat, in kilojoules, (a) required to raise the temperature of 9.25 L of water from 22.0 to 29.4 °C; (b) associated with a 33.5°C decrease in temperature in a 5.85 kg aluminum bar (specific heat capacity of aluminum
(a)
Interpretation:
The heat required to raise the temperature of 9.25 L water from 22 0C to 29.4 0C is to be calculated.
Concept introduction:
The amount of heat required in order to increase the temperature by one degree Celsius of unit mass of a substance is said to be the specific heat.
The heat required to change the temperature of a substance is related to heat capacity of the substance by the expression as:
Answer to Problem 1E
The heat required to raise the temperature of 9.25 L water from 22 0C to 29.4 0C is 286.121 kJ.
Explanation of Solution
The amount of heat required to raise the temperature of a substance is given as:
The mass of water can be calculated using the given volume of water and the density of water.
The change in temperature = (29.4 - 22.0) 0C = 7.4 0C
Specific heat of water = c = 4.18 J/g0C
Substituting the above values in equation (1) to calculate the value of Q:
Therefore, the heat required to raise the temperature of 9.25 L of water is 286.121 kJ.
(b)
Interpretation:
The quantity of heat associated with a 33.5 0C decrease in temperature in a 5.85 kg aluminum bar is to be calculated.
Concept introduction:
The amount of heat required in order to increase the temperature by one degree Celsius of unit mass of a substance is said to be the specific heat.
The heat required to change the temperature of a substance is related to heat capacity of the substance by the expression as:
Answer to Problem 1E
The quantity of heat required to decrease the temperature of aluminum bar by 33.5 0C is 176.97 kJ.
Explanation of Solution
The amount of heat required to change the temperature of a substance is given as:
The mass of aluminum is given to be
The decrease in temperature = 33.5 0C
Specific heat of aluminum = c = 0.903 J/g0C
Substituting the above values in equation (1) to calculate the value of Q:
Therefore, the heat required to decrease the temperature of 5.85 kg aluminum by 33.5 0C is 176.97 kJ.
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