Chemistry
Solids Liquids and Gases
Solids, liquids, and gases are the three main states of matter. Solids have a fixed shape and volume, with particles closely packed together. Liquids have a fixed volume but take the shape of their container, with particles that are more spread out than in solids. Gases have neither a fixed shape nor volume, with particles that are widely spaced and move freely.
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11 Key excerpts on "Solids Liquids and Gases"
- Wallace Brey(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
One States of Matter The differences we observe in the characteristics of the three states of matter—gas, liquid, and solid—depend upon the variation in the condi-tion of aggregation of the molecules of which the matter is composed. In this chapter some of the principles governing transformation of one state of matter into another are considered. Structural models for gases and liquids are discussed, and the relationships between the macro-scopic properties of these phases and the behavior and properties of individual molecules are examined, particularly from the viewpoint of the influence of forces between molecules. 1-1 MOLECULAR PICTURE OF MATTER From the properties of the gaseous state of matter, scientists have de-duced a model in which the molecules are relatively far apart and are free to move almost independently of one another. This picture is em-bodied in the kinetic theory, which describes the molecules of a gas as separated particles in continuous motion. Each molecule travels in a straight line until it collides with another molecule or strikes the wall of the vessel in which it is confined. W h e n the vessel is enlarged, mo-lecular motion causes the gas to spread throughout all the newly acces-sible space; the application of external pressure, however, readily compresses the gas into a smaller volume, for the molecules have a relatively large amount of empty space between them. In a liquid, the molecules are more restricted in their movement: They are able to roll past one another so that the liquid can flow, but it is only with considerable difficulty that they detach themselves from intimate association with other molecules in the bulk of the liquid, as they must do if the liquid is to be vaporized. In a solid, each molecule has a definitely assigned average position about which it vibrates; movement of the molecule away from its own small compartment, 2 ONE STATES OF MATTER formed by neighboring molecules, is a comparatively unusual event.
eBook - PDFFoundations of Chemistry
An Introductory Course for Science Students
- Philippa B. Cranwell, Elizabeth M. Page(Authors)
- 2021(Publication Date)
- Wiley(Publisher)
4 States of matter At the end of this chapter, students should be able to: • Describe the three main states of matter • Compare the motion of particles in solids, liquids, and gases and the strengths of interactions between particles in these materials • Describe the arrangement of particles in metals, ionic solids, and simple covalent and giant molecular structures • Explain how the physical properties of simple materials such as melting and boiling points are determined by the strengths of intermolecular forces in the materials • Understand the derivation of the ideal gas law and its relevance in defining the behaviour of gases 4.1 Introduction Chapter 2 showed that the type of bonding between atoms and the forces between molecules depend upon the nature of the elements that are bonded together. In this chapter, we will see how bonding and intermolecular forces determine the properties of materials. Most materials can be classified as solids, liquids, or gases – the three com-mon states of matter. Most substances are made up of smaller particles such as atoms, molecules, or ions. In Chapter 2, it was shown that atoms within mole-cules have bonds between them called intramolecular forces, and molecules have weaker interactions between them known as intermolecular forces. It is the strength of the intermolecular forces that determines whether the substance exists as a solid, liquid, or gas at room temperature. In solids, particles are relatively close to each other, usually in a regular arrangement. If a solid is heated, the particles gain kinetic energy and begin Foundations of Chemistry: An Introductory Course for Science Students , First Edition. Philippa B. Cranwell and Elizabeth M. Page. © 2021 John Wiley & Sons Ltd. Published 2021 by John Wiley & Sons Ltd. Companion website: www.wiley.com/go/Cranwell/Foundations
eBook - PDFChemistry
Principles and Reactions
- William Masterton, Cecile Hurley(Authors)
- 2020(Publication Date)
- Cengage Learning EMEA(Publisher)
216 ▼ Liquids and Solids 9 ▼ The painting shows water in two of its physical states: liquid and solid. Bridgeman Art Library, London/SuperStock See plastic Nature working to this end, The single atoms each to other tend, Attract, attracted to, the next in place Form’d and impell’d its neighbour to embrace. —ALEXANDER POPE From An Essay on Man: Epistle III Chapter Outline 9-1 Comparing Solids, Liquids, and Gases 9-2 Liquid-Vapor Equilibrium 9-3 Phase Diagrams 9-4 Molecular Substances; Intermolecular Forces 9-5 Network Covalent, Ionic, and Metallic Solids 9-6 Crystal Structures ▼ I In Chapter 5, we pointed out that at ordinary temperatures and pressures, all gases follow the ideal gas law. In this chapter we will examine liquids and solids. Unfor-tunately, there are no simple relations analogous to the ideal gas law that correlate the properties of these two physical states. ■ In Section 9-1 we will compare some of the properties of the three different phases and give two reasons for this difference in behavior. ■ Section 9-2 will focus on the different phases of a pure substance. We will consider different phenomena related to gas-liquid equilibria, including vapor pressure, boiling point behavior, and critical properties. ■ Section 9-3 deals with phase diagrams, which describe all these types of phase equilibria (gas-liquid, gas-solid, and liquid-solid). ■ Section 9-4 explores the relationship between particle structure, interparticle forces, and physical properties in molecular substances. ■ Section 9-5 extends the discussion to nonmolecular solids (network covalent, ionic, and metallic). ■ Section 9-6 is devoted to the crystal structure of ionic and metallic solids. 9-1 Comparing Solids, Liquids, and Gases Why are liquids and solids so different from gases? There are two reasons for this difference in behavior. 1. Molecules are much closer to one another in liquids and solids.
eBook - PDFChemistry in Focus
A Molecular View of Our World
- Nivaldo Tro(Author)
- 2018(Publication Date)
- Cengage Learning EMEA(Publisher)
Instead, they flow to assume the shape of their container. Good examples of liquid matter include water, rubbing alcohol, and vegetable oil. In gaseous matter, atoms or molecules are not in close contact but are sepa-rated by large distances. The atoms or molecules are in constant motion and often collide with each other and with the walls of their container. Consequently, gas-eous matter does not have a fixed shape or a fixed volume but rather assumes the shape and volume of its container. In addition, gaseous matter is compressible. Good examples of gaseous matter include steam, helium, and air. Table 1.1 sum-marizes the states of matter and the properties of each state. ✔ ● Self-Check 1.2 A cup of coffee is an example of: a. a liquid pure substance b. a gaseous mixture c. a solid pure substance d. a liquid mixture e. a solid mixture TABLE 1.1 The States of Matter Solid Incompressible Fixed volume Fixed shape Liquid Incompressible Fixed volume Variable shape Gas Compressible Variable volume Variable shape The Properties of Matter Every day, we tell one substance from another based on its properties. For example, we distinguish between gasoline and water because they smell different, or between sugar and salt because they taste different. The characteristics that distinguish a sub-stance and make it unique are its properties . In chemistry, we distinguish between physical properties , those properties that a substance displays without changing its composition, and chemical properties , those properties that a substance displays only when changing its composition. For example, the smell of alcohol is a physical prop-erty. When we smell alcohol, it does not change its composition. However, the flam-mability of alcohol—its tendency to burn—is a chemical property. When alcohol burns, it combines with oxygen in the air to form other substances. We can also distinguish between two different kinds of changes that occur in matter—physical change and chemical change.
eBook - ePub- Charles S. Sell(Author)
- 2019(Publication Date)
- Wiley-VCH(Publisher)
their own and will assume the shape of the container in which they are stored. The molecules making up the liquid interact weakly with each other and have no long‐range order, regular structure, or pattern of orientations of molecules. However,short‐range interactions between the molecules of a liquid will hold them together, and so a liquid will, under gravity, settle to the bottom of its container. Since the forces holding the molecules together are relatively weak, it is possible to separate them. A solid object dropped onto the surface of a liquid will penetrate it and fall to the bottom of the liquid, assuming it is denser than the liquid. The weak nature of the intermolecular forces in a liquid will also allow it to flow.Gases
Gases are very mobile and will spread equally throughout the space allowed to them. No interaction occurs between the individual molecules making up a gas.Phase Changes
Substances can be transformed from one state of matter to another. We all know that water is normally a liquid, but in winter or in a freezer, it will become solid and is known as ice. Similarly, when heated on a stove, the water in a pot will form steam, which is a gas, and evaporate. Of course, a gas close to the point of liquefaction is often referred to as avapour. These examples illustrate the effect of temperature on states of matter. The other thing that affects state of matter is pressure. A heavy weight placed on a block of ice will melt it, even if it is as cold as the ice. Water boils at 100 °C at sea level, but on top of a mountain, where the air pressure is lower, it will boil at a lower temperature. The relationships between the solid, liquid, and gas phases of a substance can be presented in what is known as a phase diagram, as shown inFigure4.7.A simple phase diagram.Figure 4.7In Figure4.7, the temperature increases from left to right along the horizontal axis, and the pressure from bottom to top along the vertical axis. The three phases of matter for our test substance are shown in the figure, and the solid lines show the transition from one phase to another. The point P where the three lines meet is called a triple point, because at this point all three phases exist together. Point C is known as the critical point,
- Frederick Bettelheim, William Brown, Mary Campbell, Shawn Farrell(Authors)
- 2019(Publication Date)
- Cengage Learning EMEA(Publisher)
140 Gases, Liquids, and Solids 5 CONTENTS 5.1 Introduction to the Three States of Matter 5.2 Gas Pressure and Measurements 5.3 The Behavior of Gases 5.4 Avogadro’s Law and the Ideal Gas Law 5.5 Dalton’s Law of Partial Pressures 5.6 The Kinetic Molecular Theory 5.7 Types of Intermolecular Attractive Forces 5.8 The Behavior of Liquids at the Molecular Level 5.1 Introduction to the Three States of Matter Various forces hold matter together causing it to take different forms. In an atomic nucleus, very strong forces of attraction keep the protons and neutrons together (Chapter 2). In an atom itself, there are attractions be-tween the positive nucleus and the negative electrons that surround it. Within molecules, atoms are attracted to each other by covalent bonds, the arrangement of which causes the molecules to assume a particular shape. Within an ionic crystal, three-dimensional shapes arise because of electro-static attractions between ions. In addition to these forces, there are intermolecular attractive forces. These forces, which are the subject of this chapter, are weaker than any of the forces already mentioned; nevertheless, they help determine whether a particular compound is a solid, a liquid, or a gas at any given temperature. Intermolecular attractive forces help hold matter together; in effect, they counteract another form of energy—kinetic energy—that tends to lead to a number of different ways for molecules to arrange themselves. Intermolecular attractive forces counteract the kinetic energy that molecules possess, which keeps them constantly moving in random, disorganized ways. Kinetic energy increases with increasing temperature. Therefore, the higher the temperature, the greater the tendency of particles to have more possible arrangements. The total energy remains the same, but it is more widely dispersed. This dispersal of energy will have some important consequences, as we will see shortly.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Academic Studio(Publisher)
The materials used in solar cells tend to have the property of preferentially absorbing the wavelengths of solar light that reach the earth surface. However, some solar cells are optimized for light absorption beyond Earth's atmosphere as well. 2. Liquid Liquid is one of the three classical states of matter. Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly constant density. A distinctive property of the liquid state is surface tension, leading to wetting phenomena. The density of a liquid is usually close to that of a solid, and much higher than in a gas. Therefore, liquid and solid are both termed condensed matter. On the other hand, as liquids and gases share the ability to flow, they are both called fluids. ________________________ WORLD TECHNOLOGIES ________________________ The formation of a spherical droplet of liquid water minimizes the surface area, which is the natural result of surface tension in liquids. Introduction Liquid is one of the three primary states of matter, with the others being solid and gas. A liquid is a fluid. Unlike a solid, the molecules in a liquid have a much greater freedom to move. The forces that bind the molecules together in a solid are only temporary in a liquid, allowing a liquid to flow while a solid remains rigid. A liquid, like a gas, displays the properties of a fluid. A liquid can flow, assume the shape of a container, and, if placed in a sealed container, will distribute applied pressure evenly to every surface in the container. Unlike a gas, a liquid may not always mix readily with another liquid, will not always fill every space in the container, forming its own surface, and will not compress significantly, except under extremely high pressures. These properties make a liquid suitable for applications such as hydraulics.
eBook - PDFBasic Physical Chemistry
The Route to Understanding
- E Brian Smith(Author)
- 2012(Publication Date)
- ICP(Publisher)
9 The States of Matter 9.1 Gases, liquids and solids Matter can exist in many forms but, most commonly, we identify three distinct states: gas, liquid and solid. The state with the lowest Gibbs free energy is the stable form of matter at any particular temperature. At low temperatures, the solid with the most negative energy is the most stable form. At high temperatures, the gaseous state with the maximum randomness prevails. At intermediate temperatures, the liquid state has the lowest free energy. If the Gibbs free energy is plotted against the temperature at constant pressure, since d G = V d P − S d T , the slopes of the lines are (∂G/∂T) P = − S . The gaseous phase with the highest entropy has the largest negative slope and will have the lowest free energy at high temperatures (Fig. 9.1). The solid phase with the lowest slope has the lowest free energy at low temperatures. The transition from one phase to another occurs where the lines intersect and where the free energies are equal. Then, G = 0 and H = TS , giving, at the melting point of the solid, fus S = fus H T fus and, at the boiling point of the liquid, vap S = vap H T vap . We can represent the equilibrium of the phases as a function of temperature and pressure as shown in Fig. 9.2 for the phase equilibria in water. Such diagrams are called phase diagrams . The lines represent the pressures and temperatures at which two phases are in equilibrium. The line AB represents the vapour pressure of liquid water and AC gives the vapour pressure of ice. AD is the melting curve on which the solid and liquid are at equilibrium. The point where all three curves meet, A, is called the triple point , which, for water, is at 273.16 K and 10.61 kPa (4.58 mm Hg) pressure, the only pressure and temperature at which the three phases can co-exist in equilibrium. 199 200 | Basic Physical Chemistry G T T fus T vap Solid Liquid Gas Fig.
eBook - PDFEngineering Materials Science
Properties, Uses, Degradation, Remediation
- H McArthur, D Spalding(Authors)
- 2004(Publication Date)
- Woodhead Publishing(Publisher)
2 STATES OF MATTER AND PHYSICAL CONSTANTS 2.1 INTRODUCTION There are three states of matter, a gas or vapour, a liquid (the most common one being water) and a solid (which may be amorphous or crystalline). These three states (or phases) are shown by water as the solid ice, the liquid water and as the vapour steam. In this Chapter we focus on water, as this compound is responsible for a wide range of building defects and deterioration mechanisms (Chapters Sand 6). 2.2GASES Gas molecules exlubit constant translocational movement (visualised as billiard balls colliding) and fill the available volume. Gas molecules are modelled as having principally translocational kinetic energy and a relatively small amount ofvibrational kinetic energy (movement which stretches the interatomic bonds, e.g, Cl-Cl, 0-0, etc.). An increase in temperature increases the translocational kinetic energy to a greater extent than the vibrational kinetic energy. A decrease in temperature results in the molecules of a gas coming into closer proximity, so that bonding can occur and the gas (water vapour) condenses to form a liquid. 2.2.1 Ideal Gas Laws If one mole of a gas is confined in volume V at temperature T, the pressure exerted by the gas, p, obeys the relationship pV =RT, where R is the universal gas constant(= 8414 J/kmol.K) and Tis absolute temperature (K). For n moles of the gas, pV = nRT, where n = m!M and mis the mass of the gas of molecular weight M. This equation is the equation of state of a perfect gas, also known as the ideal ( perfect) gas law. 2.2.2 Fundamental Kinetic Theory Equation for a Gas The kinetic energy possessed by a body by virtue of its motion is called the kinetic energy of the body. Suppose a gas molecule of mass m moving with velocity u is bought to rest in a distance s by a constant retarding force F (Figure 2.1 a). The original kinetic energy of the gas molecule is equal to Fs, and this must therefore be the work done in bringing the molecule to rest.
eBook - PDFHands-On Science and Technology for Ontario, Grade 2
An Inquiry Approach With STEM Skills and Connections
- Jennifer E. Lawson(Author)
- 2023(Publication Date)
- Portage & Main Press(Publisher)
Relative to liquids and solids, molecules in gases move faster and collide more often. Therefore, gases do not have a fixed shape and expand to fill the space they are in. Of these three states, solids are the least compressible. NOTE: The term molecule is not used in the curriculum at this level but may be introduced to aid explanations. Materials ■ plastic bags (one for each student) ■ chart paper ■ markers ■ sticky notes ■ soft butter ■ camera ■ Activity Sheet: Science and Technology Glossary (2.1.1) ■ Task Card: What Do We Know About Solids and Liquids? (2.1.2) ■ Solids and Liquids Library Sample Slips (several copies to leave at the library; print and cut apart) (2.1.3) ■ Solids and Liquids Library Activity Slips (enough for each student to use at the library; copy and cut apart) (2.1.4) Activate Have students imagine themselves as scientists who are going on a scavenger hunt. Provide each student with a plastic bag. On chart paper, record a list of the three items each “scientist” should hunt for: ■ something rough ■ something soft ■ something hard Give students three to five minutes to hunt for the items in the classroom. Tell them to put the items they find into their plastic bags. When students have found their items, have them return to their seats. Give each student three sticky notes. Ask them to write the name of or draw each item in their bag on a separate sticky note. Have students look at their items. Ask a few students: ■ What did you find? ■ How can you describe one of your objects? Have students share their descriptions. Ask: ■ What do all of your items have in common? ■ Are they all solids? ■ Are any of the objects liquids? Introduce the guided inquiry question: What do I know about solids and liquids? NOTE: Keep these sticky notes for the next activity.
eBook - ePubPhysical Chemistry
How Chemistry Works
- Kurt W. Kolasinski(Author)
- 2016(Publication Date)
- Wiley(Publisher)
The intermolecular interactions of a liquid are perhaps the most difficult to treat of the three common phases. In a gas, the distance between molecules allows us to ignore interactions in the ideal state and then add interactions as a small perturbation to the ideal model. In the solid state, the perfect order of a crystal introduces symmetry, which greatly simplifies the treatment of interactions. The result of these difficulties is that fundamental theories of the properties of liquids have been the most difficult to advance and lag considerably behind those of the gas and solid phases.Liquid metals and He are exceptional liquids. Helium has two liquid phases, which is also observed for P but still debated for H2 O and S. Helium is, however, the only elemental liquid that cannot be solidified at 1 atm pressure (25 atm are required for solidification), which means it has no liquid/solid phase boundary at atmospheric pressure. Liquid metals are electrically conductive, which indicates that electrons are delocalized because of metallic bonding. Delocalization is a manifestation of the many-body interactions mentioned above. Most molten salts are composed of ions, but there are exceptions such as HgCl2 , which has low electrical conductivity and, thus, must be composed of uncharged species.H2 O is the only naturally occurring inorganic liquid on Earth. It is a truly exceptional liquid. Indeed, if it were not the most important liquid, we might not even study its properties because of the complications of dealing with a heavily hydrogen-bonded liquid with an unusually large relative permittivity that readily autoionizes. However, as it is the most important liquid we will consequently spend considerable effort trying to understand it, and solutions in which it is a solvent.Our first-order model of a liquid begins with assuming that the molecules or atoms which comprise the liquid are nondeformable spheres with a fixed diameter. Their interactions with other molecules are independent of orientation. This is known as a hard-sphere model. A hard-sphere potential gives a good approximation to the thermal conductivity and viscosity of a fluid. This is because these properties are mainly determined by long-range repulsions rather than van der Waals attractions. Condensation of a gas into a liquid requires a potential with an attractive well. A simple and widely used semi-empirical potential is the Lennard–Jones potential (also known as L-J or 6-12 potential). It is defined in terms of the interparticle separation R
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