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Concept explainers
Calculate the amount of heat necessary to change
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Interpretation:
The amount of heat required to change
Concept introduction:
Sublimation is a process in which the substance in a solid state is directly converted into a vapor state without going through the liquid state.
In a chemical reaction, when an enthalpy is positive the value of
The heat capacity defined as the quantity of heat required to raise the temperature of the system by one degree.
Answer to Problem 6.11E
The amount of heat required to change
The value of heat is positive. Thus, it is an endothermic reaction.
Explanation of Solution
Given
The mass of ice is
The temperature of ice is
The temperature of steam is
The conversion of ice to steam involves steps, which are the warming of ice at
The required heat capacities and enthalpy of fusion and vaporization are shown below.
The overall heat required is the sum of each individual step which is shown below.
The temperature of ice is
The conversion of Celsius to Kelvin is done as,
Therefore, the conversion of
Similarly, the conversion of
Substitute the values of mass, heat capacities, and temperature in equation (1) to calculate the amount of heat required.
The conversion of joule into kilojoule is done as,
Therefore, the conversion of
Hence, the amount of heat required to change
The value of heat is positive. Thus, it is an endothermic reaction.
The amount of heat required to change
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Chapter 6 Solutions
Physical Chemistry
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- Evaporation of sweat requires energy and thus take excess heat away from the body. Some of the water that you drink may eventually be converted into sweat and evaporate. If you drink a 20-ounce bottle of water that had been in the refrigerator at 3.8 C, how much heat is needed to convert all of that water into sweat and then to vapor? (Note: Your body temperature is 36.6 oc. For the purpose of solving this problem, assume that the thermal properties of sweat are the same as for water.)arrow_forwardA student is asked to calculate the amount of heat involved in changing 10.0 g of liquid bromine at room temperature (22.5C) to vapor at 59.0C.To do this, one must use Tables 8.1 and 8.2 for information on the specific heat, boiling point, and heat of vaporization of bromine. In addition, the following step-wise process must be followed. (a) Calculate H for: Br2(l,22.5C)Br2(l,59.0C) (b) Calculate H for: Br2(l,59.0C)Br2(g,59.0C) (c) Using Hess's law, calculate H for: Br2(l,22.5C)Br2(g,59.0C)arrow_forwardDraw a diagram like Figure 2.11 that illustrates the change in enthalpy for the chemical reaction C s 2H2 g CH4 g Which is exothermic by 74.8 kJ/mol.arrow_forward
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