List of impact sections . Impact on environmental science:The gas laws and the weather 11 Impact on biochemistry and materials science:Differential scanning calorimetry 46 Impact on biology:Food and energy reserves Impact on engineering:Re in physiologand biochemistry 519场 52 6.1 Impact on materials science:Liquid crystals Impact on materials science:Ultrapurity and controlled impurity mrdeaboiogy 9. e microscopy 92 Impact on nanoscience:Quantum dots 110.1 Impact on astrophysics:Spectroscopy of stars Impact on biochemistry:The biochemical reactivity ofN and NO 385 1131 13.2 Impact on environmental science:Global warming 113.3 Impact on biochemistry:Vibrational microscopy 466 114.1 Impact on biochemistry:Vision 14 Impact on biochemistry:Fluorescence microscopy ob imaging 16.1 coil transition in polypeptides 18.1 Impact on medicine:Molecular recognition and drug design 69 119.1 Impact on biochemistry:Gel electrophoresis in genomics and proteomics 20.1 stallog 202 mpact on nanoscience na 21.1 Impact on astrophysics:The Sun as a ball of perfect gas 21.2 Impact on biochemistry:lon channels and ion pumps 770 21.3 Impact on biochemistry:Transport of non-electrolytes across biological 221 Impact on biochemistry:The kinetics of the helix-coil transition in polypeptides 23.1 Impact on environmental science:The chemistry of stratospheric ozone Impact on b CdnepHancst g ot lght during plant photosynthesis 24 25.1 Impact on biochemistry:Biosensor analysis 125.2 Impact on technology:Catalysis in the chemical industry Impact on technology:Fuel cells Impact on technology:Protecting materials against corrosion
List of impact sections I1.1 Impact on environmental science: The gas laws and the weather 11 I2.1 Impact on biochemistry and materials science: Differential scanning calorimetry 46 I2.2 Impact on biology: Food and energy reserves 52 I3.1 Impact on engineering: Refrigeration 85 I4.1 Impact on engineering and technology: Supercritical fluids 119 I5.1 Impact on biology: Gas solubility and breathing 147 I5.2 Impact on biology: Osmosis in physiology and biochemistry 156 I6.1 Impact on materials science: Liquid crystals 191 I6.2 Impact on materials science: Ultrapurity and controlled impurity 192 I7.1 Impact on engineering: The extraction of metals from their oxides 215 I7.2 Impact on biochemistry: Energy conversion in biological cells 225 I8.1 Impact on biology: Electron microscopy 253 I9.1 Impact on nanoscience: Scanning probe microscopy 288 I9.2 Impact on nanoscience: Quantum dots 306 I10.1 Impact on astrophysics: Spectroscopy of stars 346 I11.1 Impact on biochemistry: The biochemical reactivity of O2, N2, and NO 385 I13.1 Impact on astrophysics: Rotational and vibrational spectroscopy interstellar space 438 I13.2 Impact on environmental science: Global warming 462 I13.3 Impact on biochemistry: Vibrational microscopy 466 I14.1 Impact on biochemistry: Vision 490 I14.2 Impact on biochemistry: Fluorescence microscopy 494 I15.1 Impact on medicine: Magnetic resonance imaging 540 I15.2 Impact on biochemistry: Spin probes 553 I16.1 Impact on biochemistry: The helix–coil transition in polypeptides 571 I18.1 Impact on medicine: Molecular recognition and drug design 638 I19.1 Impact on biochemistry: Gel electrophoresis in genomics and proteomics 664 I19.2 Impact on technology: Conducting polymers 674 I19.3 Impact on nanoscience: Nanofabrication with self-assembled monolayers 690 I20.1 Impact on biochemistry: X-ray crystallography of biological macromolecules 711 I20.2 Impact on nanoscience: Nanowires 728 I21.1 Impact on astrophysics: The Sun as a ball of perfect gas 754 I21.2 Impact on biochemistry: Ion channels and ion pumps 770 I21.3 Impact on biochemistry: Transport of non-electrolytes across biological membranes 779 I22.1 Impact on biochemistry: The kinetics of the helix–coil transition in polypeptides 818 I23.1 Impact on environmental science: The chemistry of stratospheric ozone 853 I23.2 Impact on biochemistry: Harvesting of light during plant photosynthesis 856 I23.3 Impact on medicine: Photodynamic therapy 860 I24.1 Impact on biochemistry: Electron transfer in and between proteins 900 I25.1 Impact on biochemistry: Biosensor analysis 925 I25.2 Impact on technology: Catalysis in the chemical industry 929 I25.3 Impact on technology: Fuel cells 947 I25.4 Impact on technology: Protecting materials against corrosion 949
PART 1 Equilibrium Part 1 of the text develops the concepts that are needed for the discussion of equilibria in chemistry.Equilibria include physical change,such as fusion and vaporization,and chemical change,including electrochemistry.The discussion is in terms of thermodynamics,and particularly in terms of enthalpy and entropy. We see that we can obtain a unified view of equilibrium and the direction of spontaneous change in terms of the chemical potentials of substances.The chapters in Part 1 deal with the bulk properties of matter;those of Part 2 will show how these properties stem from the behaviour of individual atoms. 1 The properties of gases 2 The First Law 3 The Second Law 4 Physical transformations of pure substances 5 Simple mixtures 6 Phasediagrams 7 Chemical equilibrium
PART 1 Equilibrium Part 1 of the text develops the concepts that are needed for the discussion of equilibria in chemistry. Equilibria include physical change, such as fusion and vaporization, and chemical change, including electrochemistry. The discussion is in terms of thermodynamics, and particularly in terms of enthalpy and entropy. We see that we can obtain a unified view of equilibrium and the direction of spontaneous change in terms of the chemical potentials of substances. The chapters in Part 1 deal with the bulk properties of matter; those of Part 2 will show how these properties stem from the behaviour of individual atoms. 1 The properties of gases 2 The First Law 3 The Second Law 4 Physical transformations of pure substances 5 Simple mixtures 6 Phase diagrams 7 Chemical equilibrium
The properties of gases This chaot establishes the erties of gases that will be used throughout the text.It The perfect gas ins with an account of an and cho :ho y ite 1.The states of gases gases differ from those of a perfect gas,and construct an equation of state that describes 1.2 The gas laws their properties. weather Real gases 1.3 Molecular interactions The perfect gas 1.4 The van der Waals equation 1.5 The principle of corresponding ecules(or atoms)in con Checklist of key ideas nother and m Further reading intermolecua forces. Discussion questions Exercises 1.1 The states of gases Problems ce,its physical isdefined byit state.Th 一es are Pue6am T.However,it has been established experimentally that it is sufficient to specify only three of these variables,for then the fourth variable is fixed.That is,it is an experi mental fact that each substance is described by an equation of state,an equation that interrelates these four variables The general form of an equation of state i p=fT.V.n) (1.1) stance then the n equation of state,but we know the explicit form of the equation in only a few special cases.One very important example is the equation of state ofa 'perfect gas',which has the form p=nRT/V,where R is a constant.Much of the rest of this chapter will exam- ne the origin of this equation of state and its applications
The properties of gases This chapter establishes the properties of gases that will be used throughout the text. It begins with an account of an idealized version of a gas, a perfect gas, and shows how its equation of state may be assembled experimentally. We then see how the properties of real gases differ from those of a perfect gas, and construct an equation of state that describes their properties. The simplest state of matter is a gas, a form of matter that fills any container it occupies. Initially we consider only pure gases, but later in the chapter we see that the same ideas and equations apply to mixtures of gases too. The perfect gas We shall find it helpful to picture a gas as a collection of molecules (or atoms) in continuous random motion, with average speeds that increase as the temperature is raised. A gas differs from a liquid in that, except during collisions, the molecules of a gas are widely separated from one another and move in paths that are largely unaffected by intermolecular forces. 1.1 The states of gases The physical state of a sample of a substance, its physical condition, is defined by its physical properties. Two samples of a substance that have the same physical properties are in the same state. The state of a pure gas, for example, is specified by giving its volume, V, amount of substance (number of moles), n, pressure, p, and temperature, T. However, it has been established experimentally that it is sufficient to specify only three of these variables, for then the fourth variable is fixed. That is, it is an experimental fact that each substance is described by an equation of state, an equation that interrelates these four variables. The general form of an equation of state is p = f(T,V,n) (1.1) This equation tells us that, if we know the values of T, V, and n for a particular substance, then the pressure has a fixed value. Each substance is described by its own equation of state, but we know the explicit form of the equation in only a few special cases. One very important example is the equation of state of a ‘perfect gas’, which has the form p = nRT/V, where R is a constant. Much of the rest of this chapter will examine the origin of this equation of state and its applications. 1 The perfect gas 1.1 The states of gases 1.2 The gas laws I1.1 Impact on environmental science: The gas laws and the weather Real gases 1.3 Molecular interactions 1.4 The van der Waals equation 1.5 The principle of corresponding states Checklist of key ideas Further reading Discussion questions Exercises Problems
4 1 THE PROPERTIES OF GASES Table 1.1 Pressure units Name Symbol value 1Pa 1 bar 10 Pa （001325/760)Pa=13332.PA millimetres of mercury 13.322.Pa 6.394757.kp (a)Pressure Comment1.1 on thewalls ofits container The International System of units(SI, The collisions are so numerous that they exert an effectively steady force,which is experienced as a steady pressure. The SI unit of pressure,the pascal(Pa),is defined as I newton per metre-squared: 1Pa=1Nm-2 [1.2a In terms of base units 1Pa=Ikgm-s 1.2b Several other units are still widely used(Table 1.1);ofthese units,the most commonly used are atmosphere(1 atm=1.013 25 x 10 Pa exactly)and bar(1 bar=10 Pa).A pressure of 1 bar is the standard pressure for reporting data;we denote it p". Motion Self-test 1.1 Calculate the pressure(in pascals and atmospheres)exerted by a mass Equal pr Iftwo gases are in separate containers that sharea common movable wall(Fig.1.1) the gas that has the higher pressure will tend to compress(reduce the volume of)the gas that has lower pressure.The pressure of the high-pressure gas will fall as it expands is compressed.There will come a stage s no f is a sta 1.When a region of high pre librium with another gas with which it shares a movable wall. separated froma region of low pressure by (b)The measurement of pressure However,if the two pre s are identical huu
4 1 THE PROPERTIES OF GASES (a) Pressure Pressure is defined as force divided by the area to which the force is applied. The greater the force acting on a given area, the greater the pressure. The origin of the force exerted by a gas is the incessant battering of the molecules on the walls of its container. The collisions are so numerous that they exert an effectively steady force, which is experienced as a steady pressure. The SI unit of pressure, the pascal (Pa), is defined as 1 newton per metre-squared: 1 Pa = 1 N m−2 [1.2a] In terms of base units, 1 Pa = 1 kg m−1 s −2 [1.2b] Several other units are still widely used (Table 1.1); of these units, the most commonly used are atmosphere (1 atm = 1.013 25 × 105 Pa exactly) and bar (1 bar = 105 Pa). A pressure of 1 bar is the standard pressure for reporting data; we denote it p7 . Self-test 1.1 Calculate the pressure (in pascals and atmospheres) exerted by a mass of 1.0 kg pressing through the point of a pin of area 1.0 × 10−2 mm2 at the surface of the Earth. Hint. The force exerted by a mass m due to gravity at the surface of the Earth is mg, where g is the acceleration of free fall (see endpaper 2 for its standard value). [0.98 GPa, 9.7 × 103 atm] If two gases are in separate containers that share a common movable wall (Fig. 1.1), the gas that has the higher pressure will tend to compress (reduce the volume of) the gas that has lower pressure. The pressure of the high-pressure gas will fall as it expands and that of the low-pressure gas will rise as it is compressed. There will come a stage when the two pressures are equal and the wall has no further tendency to move. This condition of equality of pressure on either side of a movable wall (a ‘piston’) is a state of mechanical equilibrium between the two gases. The pressure of a gas is therefore an indication of whether a container that contains the gas will be in mechanical equilibrium with another gas with which it shares a movable wall. (b) The measurement of pressure The pressure exerted by the atmosphere is measured with a barometer. The original version of a barometer (which was invented by Torricelli, a student of Galileo) was an inverted tube of mercury sealed at the upper end. When the column of mercury is in mechanical equilibrium with the atmosphere, the pressure at its base is equal to that Comment 1.1 The International System of units (SI, from the French Système International d’Unités) is discussed in Appendix 1. Table 1.1 Pressure units Name Symbol Value pascal 1 Pa 1 N m−2 , 1 kg m−1 s −2 bar 1 bar 105 Pa atmosphere 1 atm 101.325 kPa torr 1 Torr (101 325/760) Pa = 133.32 . . . Pa millimetres of mercury 1 mmHg 133.322 . . . Pa pound per square inch 1 psi 6.894 757 . . . kPa High pressure High pressure Low pressure Low pressure Equal pressures (a) (b) (c) Movable wall Motion Fig. 1.1 When a region of high pressure is separated from a region of low pressure by a movable wall, the wall will be pushed into one region or the other, as in (a) and (c). However, if the two pressures are identical, the wall will not move (b). The latter condition is one of mechanical equilibrium between the two regions
1.1 THE STATES OF GASES 5 exerted by the atmosphere.It follows that the height of the mercury column is pro- portional to the external pressure. Example 1.1 Calculating the pressure exerted bya columnof quid Derive an cquation for the pressure at the base of a column of liquid of mass density p(rho)and height hat the surface of the Earth. efindth frplicd mg.To ca r we nee the mass m oft Answer Let the column have cross-sectional area A:then its volume is Ah and its mass is m=pAh.The force the column of this mass exerts at its base is F=mg=pAhg The pressure at the base of the column is therefore temperature (1.3) Note that the pre ssure is inder endent of the shar and cros sectional area of the column.The nn of a given height increases as the area,but so doe the area on which the force acts,so the two cancel. Self-test 12 Derive an ex ssion for the pressure at the base of a column of liquid of length /held at an angle (theta)to the vertical (1. [p=pgl cos Energy as heat Equal temperatures The pressure of a sample of gas inside a container is measured by using a pressure h is a de ice with electrical properties that depend on the pressure. n of the molecule e to a fixedl e of the arrang ment certain semiconductors also respond to pressure and are used as transducers in solid-state pressure gauges. (c)Temperature The concept of temperature springs from the observation that a change in physical state(for example,a change of volume)can occur when two objects are in contact y with one another,as when a red-hot metal is plunged into water.Later(Section 2.1) we shall see that the change ins tate can be interpreted as arising from a flow of energy tto another.The temperature,T,is the property that 1 Energy flows as heat froma region edirection ature ifthe ntact y con gh a diathe they ar mic wall,as in (a)and ver,if the tw It will prove useful to distinguish between two types of boundary that can separate nsfer of energy as heat even though the the objects.A boundary is diathermic(thermally conducting)if a change of state is ( separa by a diatherm observed when two objects at different temperatures are brought into contact.A to the two regions being at therm The word the Greek forou equilibrium
1.1 THE STATES OF GASES 5 l 1 1 The word dia is from the Greek for ‘through’. exerted by the atmosphere. It follows that the height of the mercury column is proportional to the external pressure. Example 1.1 Calculating the pressure exerted by a column of liquid Derive an equation for the pressure at the base of a column of liquid of mass density ρ (rho) and height h at the surface of the Earth. Method Pressure is defined as p = F/A where F is the force applied to the area A, and F = mg. To calculate F we need to know the mass m of the column of liquid, which is its mass density, ρ, multiplied by its volume, V: m = ρV. The first step, therefore, is to calculate the volume of a cylindrical column of liquid. Answer Let the column have cross-sectional area A; then its volume is Ah and its mass is m = ρAh. The force the column of this mass exerts at its base is F = mg = ρAhg The pressure at the base of the column is therefore (1.3) Note that the pressure is independent of the shape and cross-sectional area of the column. The mass of the column of a given height increases as the area, but so does the area on which the force acts, so the two cancel. Self-test 1.2 Derive an expression for the pressure at the base of a column of liquid of length l held at an angle θ (theta) to the vertical (1). [p = ρgl cos θ] The pressure of a sample of gas inside a container is measured by using a pressure gauge, which is a device with electrical properties that depend on the pressure. For instance, a Bayard–Alpert pressure gauge is based on the ionization of the molecules present in the gas and the resulting current of ions is interpreted in terms of the pressure. In a capacitance manometer, the deflection of a diaphragm relative to a fixed electrode is monitored through its effect on the capacitance of the arrangement. Certain semiconductors also respond to pressure and are used as transducers in solid-state pressure gauges. (c) Temperature The concept of temperature springs from the observation that a change in physical state (for example, a change of volume) can occur when two objects are in contact with one another, as when a red-hot metal is plunged into water. Later (Section 2.1) we shall see that the change in state can be interpreted as arising from a flow of energy as heat from one object to another. The temperature, T, is the property that indicates the direction of the flow of energy through a thermally conducting, rigid wall. If energy flows from A to B when they are in contact, then we say that A has a higher temperature than B (Fig. 1.2). It will prove useful to distinguish between two types of boundary that can separate the objects. A boundary is diathermic (thermally conducting) if a change of state is observed when two objects at different temperatures are brought into contact.1 A p F A Ahg A == = gh ρ ρ Low temperature High temperature Low temperature High temperature Diathermic wall Energy as heat Equal temperatures (a) (b) (c) Fig. 1.2 Energy flows as heat from a region at a higher temperature to one at a lower temperature if the two are in contact through a diathermic wall, as in (a) and (c). However, if the two regions have identical temperatures, there is no net transfer of energy as heat even though the two regions are separated by a diathermic wall (b). The latter condition corresponds to the two regions being at thermal equilibrium