Textbook Question
The change of state from liquid H2O to gaseous H2O has ∆H = +9.72 kcal/mol(+40.7 kJ/mol) and ∆S = -26.1 cal/(mol • K) [-109 J/(mol •K)].
a. Is the change from liquid to gaseous H2O favored or unfavored by ∆H? By ∆S?
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Ch.8 Gases, Liquids and Solids
McMurry8th EditionFundamentals of GOBISBN: 9780134015187
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Table of contents
- Ch.1 Matter and Measurements27
- Ch.2 Atoms and the Periodic Table20
- Ch.3 Ionic Compounds8
- Ch.4 Molecular Compounds23
- Ch.5 Classification & Balancing of Chemical Reactions12
- Ch.6 Chemical Reactions: Mole and Mass Relationships28
- Ch.7 Chemical Reactions: Energy, Rate and Equilibrium64
- Ch.8 Gases, Liquids and Solids24
- Ch.9 Solutions52
- Ch.10 Acids and Bases25
- Ch.11 Nuclear Chemistry22
- Ch.12 Introduction to Organic Chemistry: Alkanes57
- Ch.13 Alkenes, Alkynes, and Aromatic Compounds47
- Ch.14 Some Compounds with Oxygen, Sulfur, or a Halogen50
- Ch.15 Aldehydes and Ketones45
- Ch.16 Amines42
- Ch.17 Carboxylic Acids and Their Derivatives57
- Ch.18 Amino Acids and Proteins82
- Ch.19 Enzymes and Vitamins63
- Ch.20 Carbohydrates44
- Ch.21 The Generation of Biochemical Energy65
- Ch.22 Carbohydrate Metabolism45
- Ch.23 Lipids42
- Ch.24 Lipid Metabolism33
- Ch.25 Protein and Amino Acid Metabolism24
- Ch.26 Nucleic Acids and Protein Synthesis45
Chapter 8, Problem 2a
Would you expect the boiling points to increase or decrease in the following series? Explain.
a. Kr, Ar, Ne
Verified step by step guidance1
Identify the trend in the periodic table: Krypton (Kr), Argon (Ar), and Neon (Ne) are all noble gases located in Group 18 of the periodic table. They are arranged in order of increasing atomic number, with Neon being the smallest and Krypton the largest.
Understand the relationship between atomic size and intermolecular forces: As the atomic size increases, the number of electrons also increases. This leads to stronger London dispersion forces (a type of van der Waals force), which are the primary intermolecular forces in noble gases.
Relate intermolecular forces to boiling points: Stronger intermolecular forces require more energy to overcome, resulting in higher boiling points. Therefore, the boiling point is expected to increase as the atomic size increases.
Apply the trend to the given series: Neon (Ne) has the smallest atomic size and weakest London dispersion forces, so it will have the lowest boiling point. Argon (Ar) is larger than Neon, so it will have a higher boiling point. Krypton (Kr) is the largest, so it will have the highest boiling point in the series.
Conclude the trend: The boiling points in the series (Ne, Ar, Kr) are expected to increase as you move from Neon to Krypton due to the increasing strength of London dispersion forces with atomic size.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Noble Gases
Noble gases, including Krypton (Kr), Argon (Ar), and Neon (Ne), are a group of elements characterized by their full valence electron shells, making them largely inert and non-reactive. Their physical properties, such as boiling points, are influenced by their atomic size and intermolecular forces.
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Test for Anions
Atomic Size and Boiling Point
The boiling point of a substance is affected by its atomic size and the strength of the intermolecular forces present. In noble gases, larger atoms have more electrons, leading to stronger London dispersion forces, which typically result in higher boiling points as the atomic size increases.
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Trends in the Periodic Table
In the periodic table, boiling points of noble gases increase down the group due to increasing atomic mass and size. As you move from Neon to Argon to Krypton, the atomic size increases, leading to stronger dispersion forces and, consequently, higher boiling points.
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Related Practice
Textbook Question
The change of state from liquid H2O to gaseous H2O has ∆H = +9.72 kcal/mol(+40.7 kJ/mol) and ∆S = -26.1 cal/(mol • K) [-109 J/(mol •K)].
b. What are the values of ∆H and ∆S (in kcal/mol and kJ/mol) for the change from gaseous to liquid H2O?
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Textbook Question
A local weather station reports the barometric pressure as 29.5 inHg (inches of Hg). Convert this pressure to torr and to atm.
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Textbook Question
Determine the percent composition of air in the lungs from the following composition in partial pressures: PN2= 573 mmHg, PO2 = 100 mmHg, PCO2 = 40 mmHg, and PH2O = 47 mmHg; all at 37 °C and 1 atm pressure.
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Textbook Question
Compare the ∆Hvap values for water, isopropyl alcohol, ether, and ammonia, and order them from lowest to highest. Explain the rank order based on intermolecular attractive forces.
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