# General Chemistry

## Linus Pauling

- 992 pages
- English
- ePUB (mobile friendly)
- Available on iOS & Android

# General Chemistry

## Linus Pauling

## About This Book

`An excellent text, highly recommended.` *— Choice*When it was first published, this first-year chemistry text revolutionized the teaching of chemistry by presenting it in terms of unifying principles instead of as a body of unrelated facts. Those principles included modern theories of atomic and molecular structure, quantum mechanics, statistical mechanics and thermodynamics. In addition, Dr. Pauling attempted to correlate the theories with descriptive chemistry, the observed properties of substances, to introduce the student to the multitude of chemical substances and their properties.

In this extensively revised and updated third edition, the Nobel Prize–winning author maintains an excellent balance between theoretical and descriptive material, although the amount of descriptive chemistry has been decreased somewhat, and the presentation of the subject, especially in relation to the nonmetals, has been revised in such a way as to permit greater correlation with the electronic structure of atoms, especially electronegativity.

The principles of quantum mechanics are discussed on the basis of the de Broglie wavelength of the electron. The quantized energy levels of a particle in a box are derived by means of a simple assumption about the relation of the de Broglie waves to the walls of the box. No attempt is made to solve the Schrodinger wave equation for other systems, but the wave functions of hydrogen-like electrons are presented and discussed in some detail, and the quantum states for other systems are also covered. Statistical mechanics is introduced before thermodynamics, and the discussion of thermodynamics is based on it. This arrangement reflects the author's belief that beginning students can understand statistical mechanics better than chemical thermodynamics.

Aimed at first-year college students who plan to major in chemistry or closely related fields, the book is written in a logical, clear and understandable style. In addition, many excellent figures are included, along with numerous problems and 75 pages of appendixes covering such topics as symmetry of molecules and crystals, hybrid bond orbitals, and magnetic properties of substances.

## Frequently asked questions

## Information

## 1

## The Nature and Properties of Matter

### 1-1. Matter and Chemistry

*materia,*meaning wood or other material) may be defined as any kind of mass-energy (see Section 1-2) that moves with velocities less than the velocity of light, and radiant energy as any kind of mass-energy that moves with the velocity of light.

*substances.*Chemistry is the science of substancesātheir structure, their properties, and the reactions that change them into other substances.

### 1-2. Mass and Energy

*Einstein equation,*which is an essential part of the theory of relativity:

*E*is the amount of energy (J),

*m*is the mass (kg), and

*c*is the velocity of light (m s

^{ā1}).* The velocity of light, c, is one of the fundamental constants of nature;ā its value is 2.9979 Ć 10

^{8}meters per second.

*m*of the matter obtained by the conversion of an amount

*E*of radiant energy or convertible into this amount of radiant energy is given by the Einstein equation. Experimental verification of the Einstein equation has been obtained by the study of processes involving nuclei of atoms. The nature of these processes will be described in later chapters in this book.

*law of conservation of mass,*in which the mass to be conserved includes both the mass of the matter in the system and the mass of the radiant energy in the system.

### 1-3. The International System of Units

*SystĆ©me International*), was formally adopted by the General Conference of Weights and Measures in 1960.

*kilogram,*is defined as the mass of a standard object made of a platinum-iridium alloy and kept in Paris. One pound is equal approximately to 453.59 g, and hence 1 kg is equal approximately to 2.205 lb. (Note that it has become customary for the abbreviation of units in the metric system to be written without periods.) There is at the present time a flaw in the International System, in that the name for the unit of mass involves a prefix, kilo. This flaw will remain until agreement about a new name and symbol has been reached. In the meantime we must remember that 1 milligram (symbol 1 mg, not 1

*Ī¼*kg) is one millionth of the unit of mass, not one thousandth, as indicated by the prefix milli.

*meter*(m), is equal to about 39.37 inches (1 inch equals exactly 2.54 cm). The meter was formerly defined as the distance between two engraved lines on a standard platinum-iridium bar kept in Paris by the International Bureau of Weights and Measures; in 1960 it was redefined, by international agreement, as 1,650,763.73 wavelengths of the orange-red spectral line* of krypton 86.

*second*(s). It is defined as the interval occupied by 9,192,631,770 cycles of the microwave line* of cesium 133 with wavelength about 3.26 cm. The second was formerly defined as 1/86400th of the mean solar day.

*cubic meter,*m

^{3}. In chemistry a unit that is much usedā is the liter, symbol 1, which is 1 Ć 10

^{ā3}m

^{3}. The milliliter, 1 Ć 10

^{ā3}1, is equal to the cubic centimeter: 1 ml = 1 cm

^{3}.

*newton*(N), which is defined as the force needed to accelerate a mass of 1 kg by 1 m s

^{ā2}. The newton is 10

^{5}dyne (the dyne, the unit of force in the cgs system, is the force that accelerates 1 g by 1 cm s

^{ā2}). The IS unit of energy, the

*joule*ā” (J), is the work done by 1 newton in the distance 1 meter: 1 J = 1 N m = 10

^{7}erg = 10

^{7}dyne cm.

*calorie*has been extensively used as the unit of energy. The thermochemical calorie, defined as 4.184 J (Appendix I), is approximately the amount of energy needed to raise the temperature of 1 g of water by 1Ā°C. The large calorie (kcal or Cal) is 10

^{3}cal. In this book we shall use the joule in most of the tables and discussions. Since most thermochemical reference books use the calorie or kilocalorie, you will find it worth while to remember the conversion factor:

**Example 1-1.**Niagara Falls (Horseshoe) is 160 feet high. How much warmer is the water at the bottom than at the top, as the result of the conversion of potential energy into thermal energy? The standard acceleration of gravity is 9.80665 m s

^{ā2}.

**Solution.**The gravitational force on a mass of 1 kg at the earthās surface is 9.80665 N. The change is potential energy of 1 kg over a vertical distance

*h*(in meters) is 9.80665 Ć

*h*J. In this problem

*h*has the value 0.3048 Ć 160 = 48.77 m (conversion factor from Appendix I); hence the change in potential energy produces 9.80665 Ć 48.77 = 478 J of thermal energy. The energy required to raise the temperature of 1 kg of water by 1Ā°C is given above as 1 kcal = 4.184 kJ = 4184 J. Hence the increase in temperature of the water is 478/4184 = 0.114Ā°C.

**Example 1-2.**When 2 kg of uranium 235 undergoes nuclear fission (as in the detonation of the Hiroshima atomic bomb on 6 August 1945), 1.646 Ć 10

^{14}J of radiant energy and thermal energy is liberated. What is the mass of the material products of the reaction?

**Solution.**We can calculate the mass of the liberated energy by the use of the Einstein equation (1-1). Rewriting this equation by dividing each side by

*c*and introducing the values of

^{2}*E*and

*c,*we obtain

**Example 1-3.**It is found by experiment that when 1 kg of glyceryl trinitrate (nitroglycerine) is exploded, the amount 8.0 Ć 10

^{6}J of energy is liberated. What is the mass of the products of the explosion?

**Solution.**This example is to be solved in exactly the same way as the preceding one. The mass of the radiant energy that is produced by the explosion is obtained by dividing the energy,

*E,*by the square of the velocity of light:

^{10}), is so small that for practical purposes we may say that there is conservation of mass in ordinary chemical reactions.

### 1-4. Temperature

*Temperature*is the quality that determines the direction in which thermal energy flowsāit flows from the object at higher temperature to the object at lower temperature.