Textbook Question
Using energy values from TABLE 3.8, determine each of the following:
c. If Charles consumes 1800 kcal per day, he will maintain his weight. Would he lose weight on his new diet?
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Ch.3 Matter and Energy
Timberlake13th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9780134421353
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Table of contents
- Ch.1 Chemistry in Our Lives11
- Ch.2 Chemistry and Measurements80
- Ch.3 Matter and Energy54
- Ch.4 Atoms and Elements51
- Ch.5 Nuclear Chemistry42
- Ch.6 Ionic and Molecular Compounds57
- Ch.7 Chemical Quantities and Reactions41
- Ch.8 Gases29
- Ch.9 Solutions51
- Ch.10 Acids and Bases and Equilibrium65
- Ch.11 Introduction to Organic Chemistry: Hydrocarbons78
- Ch.12 Alcohols, Thiols, Ethers, Aldehydes, and Ketones83
- Ch.13 Carbohydrates54
- Ch.14 Carboxylic Acids, Esters, Amines, and Amides90
- Ch.15 Lipids61
- Ch.16 Amino Acids, Proteins, and Enzymes84
- Ch.17 Nucleic Acids and Protein Synthesis83
- Ch.18 Metabolic Pathways and ATP Production67
Timberlake13th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9780134421353Not the one you use?Change textbook
Chapter 3, Problem 53c
Using the values for the heat of fusion, specific heat of water, and/or heat of vaporization, calculate the amount of heat energy in each of the following:
c. kilojoules needed to melt 24.0 g of ice at 0 °C, warm the liquid to 100 °C, and change it to steam at 100 °C
Verified step by step guidance1
Step 1: Identify the three stages of the process: (1) melting the ice at 0 °C, (2) heating the liquid water from 0 °C to 100 °C, and (3) vaporizing the water at 100 °C. Each stage requires a separate calculation.
Step 2: For the first stage (melting the ice), use the formula for heat energy: Q = m × ΔH_fusion, where 'm' is the mass of the ice (24.0 g) and ΔH_fusion is the heat of fusion of water (334 J/g). Convert the result to kilojoules by dividing by 1000.
Step 3: For the second stage (heating the liquid water), use the formula Q = m × c × ΔT, where 'm' is the mass of the water (24.0 g), 'c' is the specific heat of water (4.18 J/g·°C), and ΔT is the temperature change (100 °C - 0 °C = 100 °C). Again, convert the result to kilojoules.
Step 4: For the third stage (vaporizing the water), use the formula Q = m × ΔH_vaporization, where 'm' is the mass of the water (24.0 g) and ΔH_vaporization is the heat of vaporization of water (2260 J/g). Convert the result to kilojoules.
Step 5: Add the heat energy values from all three stages to find the total heat energy required. Ensure all values are in kilojoules before summing them up.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Heat of Fusion
The heat of fusion is the amount of energy required to change a substance from solid to liquid at its melting point without changing its temperature. For water, this value is approximately 334 joules per gram. In the context of the question, it is essential for calculating the energy needed to melt ice into liquid water.
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Heat Capacity
Specific Heat Capacity
Specific heat capacity is the amount of heat energy required to raise the temperature of one gram of a substance by one degree Celsius. For water, this value is about 4.18 joules per gram per degree Celsius. This concept is crucial for determining the energy needed to warm the melted ice from 0 °C to 100 °C.
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Heat of Vaporization
The heat of vaporization is the amount of energy needed to convert a unit mass of a liquid into vapor without a change in temperature. For water, this value is approximately 2260 joules per gram. This concept is necessary for calculating the energy required to convert the liquid water at 100 °C into steam.
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Related Practice
Textbook Question
Identify each of the following changes of state as melting, freezing, sublimation, or deposition:
c. Heat is removed from 125 g of liquid water at 0 °C.
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Textbook Question
Identify each of the following changes of state as melting, freezing, sublimation, or deposition:
d. Frost (ice) forms on the walls of a freezer unit of a refrigerator.
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Textbook Question
Using energy values from TABLE 3.8, determine each of the following:
d. If expending 3500 kcal is equal to a loss of 1.0 lb, how many days will it take Charles to lose 5.0 lb?
Textbook Question
Identify each of the following changes of state as melting, freezing, sublimation, or deposition:
b. Snow on the ground turns to liquid water.
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Textbook Question
For the amount of exercise that Charles did for one week in part a, if expending 3500 kcal is equal to a loss of 1.0 lb, how many pounds did he lose?
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