Textbook Question
Which molecule has polar bonds but is nonpolar? (LO 8.6) (a) SF6 (b) SF2 (c) F2 (d) NF3
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Ch.11 - Liquids & Phase Changes
McMurry8th EditionChemistryISBN: 9781292336145
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Table of contents
- Ch.1 - Chemical Tools: Experimentation & Measurement170
- Ch.2 - Atoms, Molecules & Ions160
- Ch.3 - Mass Relationships in Chemical Reactions169
- Ch.4 - Reactions in Aqueous Solution199
- Ch.5 - Periodicity & Electronic Structure of Atoms102
- Ch.6 - Ionic Compounds: Periodic Trends and Bonding Theory92
- Ch.7 - Covalent Bonding and Electron-Dot Structures61
- Ch.8 - Covalent Compounds: Bonding Theories and Molecular Structure59
- Ch.9 - Thermochemistry: Chemical Energy122
- Ch.10 - Gases: Their Properties & Behavior155
- Ch.11 - Liquids & Phase Changes54
- Ch.12 - Solids and Solid-State Materials73
- Ch.13 - Solutions & Their Properties120
- Ch.14 - Chemical Kinetics98
- Ch.15 - Chemical Equilibrium125
- Ch.16 - Aqueous Equilibria: Acids & Bases110
- Ch.17 - Applications of Aqueous Equilibria147
- Ch.18 - Thermodynamics: Entropy, Free Energy & Equilibrium86
- Ch.19 - Electrochemistry154
- Ch.20 - Nuclear Chemistry96
- Ch.21 - Transition Elements and Coordination Chemistry156
- Ch.22 - The Main Group Elements187
- Ch.23 - Organic and Biological Chemistry51
Chapter 11, Problem 6
Consider a compound that has a melting point at 65 °C and a boiling point at 175 °C. Which of the following images represents a heating curve for the compound from 40 °C to 200 °C? (LO 11.5)
Verified step by step guidance1
Step 1: Understand what a heating curve is. A heating curve is a plot of temperature versus time. It shows how the temperature of a substance changes as heat is added at a constant rate. The flat sections of the curve represent the phase changes, where the substance is transitioning from one state of matter to another (solid to liquid or liquid to gas). During these phase changes, the temperature remains constant.
Step 2: Identify the phase changes in the problem. The compound has a melting point at 65 °C and a boiling point at 175 °C. This means that the compound transitions from solid to liquid at 65 °C and from liquid to gas at 175 °C.
Step 3: Visualize the heating curve. The heating curve should start at a temperature below 65 °C (since the initial temperature is 40 °C), then rise until it reaches 65 °C, where it should remain flat as the compound melts. After all the solid has melted, the temperature should start to rise again until it reaches 175 °C, where it should remain flat as the compound boils. After all the liquid has boiled, the temperature should start to rise again until it reaches 200 °C.
Step 4: Compare the heating curve you visualized with the images provided. The correct image should match the description from step 3.
Step 5: Remember that the slope of the curve represents the rate of temperature change. The steeper the slope, the faster the temperature is changing. During phase changes (melting and boiling), the slope should be zero because the temperature is not changing.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Heating Curve
A heating curve is a graphical representation that shows the change in temperature of a substance as it is heated over time. It illustrates the phases of matter (solid, liquid, gas) and the energy changes associated with phase transitions, such as melting and boiling. The curve typically features flat sections where phase changes occur, indicating that temperature remains constant while heat is added.
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Calculations with Heating and Cooling Curves
Phase Changes
Phase changes refer to the transitions between solid, liquid, and gas states of matter, which occur at specific temperatures and pressures. For the compound in question, melting occurs at 65 °C, transitioning from solid to liquid, while boiling occurs at 175 °C, transitioning from liquid to gas. Understanding these phase changes is crucial for interpreting the heating curve and identifying the correct representation.
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Melting and Boiling Points
The melting point is the temperature at which a solid becomes a liquid, while the boiling point is the temperature at which a liquid becomes a gas. These points are characteristic of a substance and are influenced by intermolecular forces. In this case, the compound's melting point at 65 °C and boiling point at 175 °C are essential for determining the segments of the heating curve that correspond to solid, liquid, and gas phases.
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Related Practice
Textbook Question
Three identical tubes are filled with different liquids; water, ethylene glycol, and olive oil. A small steel sphere was dropped into the tube, and the time it took to fall to the bottom was recorded. Which property of liquids is responsible for the differences in time for the sphere to fall through the liquid? (LO 11.1)(a) Surface tension(b) Boiling point(c) Viscosity(d) Vapor pressure