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Ch.11 - Liquids & Phase Changes
McMurry - Chemistry 8th Edition
McMurry8th EditionChemistryISBN: 9781292336145당신이 사용하는 게 아니라요?교과서 변경
11장, 문제 19

The following compound undergoes a phase transition from the solid to the smectic liquid crystal phase at 121 °C. Upon further heating, the compound undergoes another transition to liquid phase at 131 °C. Molecular arrangement of a compound at 135 °C, showing liquid phase structure.
(a) Which image represents the arrangement of molecules at 125 °C?

검증된 단계별 안내
1
Identify the phase transitions mentioned in the problem: solid to smectic liquid crystal at 121 °C and smectic liquid crystal to liquid at 131 °C.
Determine the temperature range for each phase: solid below 121 °C, smectic liquid crystal between 121 °C and 131 °C, and liquid above 131 °C.
Recognize that 125 °C falls between 121 °C and 131 °C, indicating the smectic liquid crystal phase.
Understand the characteristics of the smectic liquid crystal phase: molecules are arranged in layers with some degree of order within each layer.
Conclude that the image representing the arrangement of molecules at 125 °C should show a layered structure typical of the smectic liquid crystal phase.

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이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Phase Transitions

Phase transitions refer to the changes in the state of matter, such as solid, liquid, and gas, that occur due to variations in temperature or pressure. In this context, the compound transitions from solid to smectic liquid crystal at 121 °C and then to a liquid phase at 131 °C. Understanding these transitions is crucial for predicting molecular arrangements at specific temperatures.
추천 영상:
가이드 코스
03:22
Phase Changes in Diagrams

Liquid Crystal Phases

Liquid crystals are substances that exhibit properties between those of conventional liquids and solid crystals. The smectic phase, mentioned in the question, is characterized by layered structures where molecules are arranged in parallel layers, allowing for some fluidity. Recognizing the characteristics of different liquid crystal phases helps in visualizing molecular arrangements at various temperatures.
추천 영상:
가이드 코스
03:22
Phase Changes in Diagrams

Molecular Arrangement

Molecular arrangement refers to the specific organization of molecules within a phase. At 125 °C, which is between the smectic and liquid phases, the arrangement will reflect properties of both states. Analyzing the provided image of the liquid phase at 135 °C can help infer the likely arrangement at 125 °C, as the molecules will still exhibit some ordered structure typical of liquid crystals.
추천 영상:
가이드 코스
02:38
Molecular Polarity