Textbook Question
The chlorofluorocarbon refrigerant trichlorofluoromethane, CCl3F, has Pvap = 100.0 mm Hg at -23 °C and ΔHvap= 24.77 kJ>mol.(b) What is ΔSvap for trichlorofluoromethane?
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Ch.11 - Liquids & Phase Changes
McMurry8th EditionChemistryISBN: 9781292336145
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Table of contents
- Ch.1 - Chemical Tools: Experimentation & Measurement143
- Ch.2 - Atoms, Molecules & Ions134
- Ch.3 - Mass Relationships in Chemical Reactions149
- Ch.4 - Reactions in Aqueous Solution157
- Ch.5 - Periodicity & Electronic Structure of Atoms92
- Ch.6 - Ionic Compounds: Periodic Trends and Bonding Theory73
- Ch.7 - Covalent Bonding and Electron-Dot Structures47
- Ch.8 - Covalent Compounds: Bonding Theories and Molecular Structure51
- Ch.9 - Thermochemistry: Chemical Energy104
- Ch.10 - Gases: Their Properties & Behavior138
- Ch.11 - Liquids & Phase Changes43
- Ch.12 - Solids and Solid-State Materials56
- Ch.13 - Solutions & Their Properties98
- Ch.14 - Chemical Kinetics79
- Ch.15 - Chemical Equilibrium107
- Ch.16 - Aqueous Equilibria: Acids & Bases94
- Ch.17 - Applications of Aqueous Equilibria125
- Ch.18 - Thermodynamics: Entropy, Free Energy & Equilibrium66
- Ch.19 - Electrochemistry130
- Ch.20 - Nuclear Chemistry73
- Ch.21 - Transition Elements and Coordination Chemistry122
- Ch.22 - The Main Group Elements155
- Ch.23 - Organic and Biological Chemistry43
Chapter 11, Problem 72
Two compounds (labeled I and II) have a liquid crystal state. Predict which compound has a higher temperature associ- ated with the solid to liquid crystal phase change. Explain your reasoning.
Verified step by step guidance1
Examine the structures of compounds I and II in the provided image.
Identify the functional groups and structural features of each compound.
Consider the molecular interactions that could affect the phase change temperature, such as hydrogen bonding, van der Waals forces, and dipole-dipole interactions.
Compare the rigidity and symmetry of the molecular structures, as these can influence the stability of the solid and liquid crystal phases.
Predict which compound has a higher temperature associated with the solid to liquid crystal phase change based on the analysis of molecular interactions and structural features.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Liquid Crystal Phases
Liquid crystals are materials that exhibit properties between those of liquids and solid crystals. They can flow like a liquid but have some degree of order, particularly in their molecular arrangement. The transition between solid and liquid crystal states involves changes in temperature and can be influenced by molecular structure and interactions.
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Phase Transition Temperature
The phase transition temperature is the specific temperature at which a substance changes from one phase to another, such as from solid to liquid crystal. This temperature is influenced by intermolecular forces, molecular weight, and structural characteristics of the compounds. Higher phase transition temperatures typically indicate stronger intermolecular interactions.
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Intermolecular Forces
Intermolecular forces are the forces of attraction or repulsion between molecules. These forces, including hydrogen bonding, dipole-dipole interactions, and van der Waals forces, play a crucial role in determining the physical properties of substances, including their melting points and phase transition temperatures. Stronger intermolecular forces generally lead to higher phase transition temperatures.
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Related Practice
Textbook Question
Benzene has a melting point of 5.53 °C and a boiling point of 80.09 °C at atmospheric pressure. Its density is0.8787 g>cm3 when liquid and 0.899 g>cm3 when solid; it has Tc = 289.01 °C, Pc = 48.34 atm, Tt = 5.52 °C, and Pt = 0.0473 atm. Starting from a point at 200 K and66.5 atm, trace the following path on a phase diagram. (1) First, increase T to 585 K while keeping P constant.(2) Next, decrease P to 38.5 atm while keeping T constant.(3) Then, decrease T to 278.66 K while keeping P constant.(4) Finally, decrease P to 0.0025 atm while keeping Tconstant.What is your starting phase, and what is your final phase?
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Textbook Question
Substance X has a vapor pressure of 100 mm Hg at its triple point (48 °C). When 1 mol of X is heated at 1 atm pres- sure with a constant rate of heat input, the following heating curve is obtained: (b) For each of the following, choose which phase of X (solid, liquid, or gas) fits the description.(iii) Has the greatest specific heat
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Textbook Question
The compound cholesteryl benzoate is a rod-like molecule that undergoes a phase change from the solid to the liq- uid crystal phase at 145.5 °C. When cholesteryl benzoate is mixed with cholesteryl oleyl carbonate, a molecule with a curved shape, the temperature of the solid to liquid crys- tal transition changes. Predict if the transition temperature increases or decreases and explain your reasoning.
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Textbook Question
Intermolecular forces are important in creating ordered arrangements in liquid crystals. What types of intermolecu- lar forces exist in a sample of the following compound?
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