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    ❒ Carboxylic acids are weak acids, typically having pKa values in the range of 3–5. Alcohols, by comparison, have pKa values in the range of 15–18, and essentially do not give up a proton unless exposed to a very strong base. ❒ To understand the reasons for this difference, let’s consider acetic acid …

  Introduction ❒The gas laws help us to predict the behavior of gases, but they do not explain what happens at the molecular level to cause the changes we observe in the macroscopic world. For example, why does a gas expand on heating? ❒ In the nineteenth century, a number …

    ❒ When a weak acid or a weak base is dissolved in water, partial dissociation occurs. Thus, for nitrous acid, we can write:   where Ka is the acid dissociation constant for nitrous acid. ❒In an analogous way, the base dissociation constant for ammonia is   ❒Notice that …

  Before you solve these problems , you can read this subject for Dalton’s Law of Partial Pressures (Statement, Mathematical,Importance, Application). Problem (1): A mixture of oxygen and neon contains oxygen at a pressure of 726 torr and neon at a pressure of 44 torr. What is the pressure of the …

  ❒ Thus far we have concentrated on the behavior of pure gaseous substances, but experimental studies very often involve mixtures of gases. ❒ For example, for a study of air pollution, we may be interested in the pressure-volume temperature relationship of a sample of air, which contains several gases. …

  ❒ In the previous subject we talk about the concept of Hybridization and the types of Hybridization, but in this subject we will talk about Hybridization and Shapes of Molecules. ❒ Diatomic molecules must all be invariably linear but tri-and tetra-atomic molecules have several possible geometrical structures. In this …

Density of gas From ideal gas equation: If we rearrange the ideal gas equation, we can calculate the density of a gas:   The number of moles of the gas, n , is given by:     where m is the mass of the gas in grams and µ is its molar mass. …

  The Molar Mass of a Gaseous Substance ❒ From what we have seen so far, you may have the impression that the molar mass of a substance is found by examining its formula and summing the molar masses of its component atoms. However, this procedure works only if the …

     While formation of simple molecules could be explained adequately by overlap of atomic orbitals, the formation of molecules of Be, B and C present problems of greater magnitude having no solution with the previous theory. To explain fully the tendency of these atoms to form bonds and the …

    ❒ The strength of a Brønsted–Lowry acid depends on the extent to which a proton can be separated from it and transferred to a base. Removing the proton involves breaking a bond to the proton, and it involves making the conjugate base more electrically negative. Acidity within The …

    ❒ For a reaction to be practical, the equilibrium must favor the products, and the reaction rate must be fast enough to form them in a reasonable time. These two conditions depend on the thermodynamics and the kinetics of a reaction, respectively. ❒Thermodynamics describes energy and equilibrium. How …

  How To Predict the Outcome of Acid–Base Reactions  ❒The following table gives the approximate pKa values for a range of representative compounds.   ❒While you probably will not be expected to memorize all of the pKa values in the table , it is a good idea to begin to learn the …

      ❒Many organic reactions involve the transfer of a proton by an acid–base reaction. An important consideration, therefore, is the relative strengths of compounds that could potentially act as Brønsted–Lowry acids or bases in a reaction. ❒In contrast to the strong acids, such as HCl and H2SO4, acetic …

  (a) Formation of H2molecule   ❒Each hydrogen atom has one electron in 1s-orbital. ❒Two such atoms join to form a molecule of hydrogen. ❒In this case s–s overlapping between two 1s-orbitals of hydrogen atoms taken place resulting in the formation of hydrogen molecule. ❒There exists a sigma bond between …

    Example (1): Calculate the volume of a sample of gas originally occupying 908 mL at 717 torr and 20 oC after its temperature and pressure are changed to 72 oC and 1.07 atm. Solution Again, tabulating the data is a good idea. The volume can be stated in …

  The Ideal Gas Equation ❒ Let us summarize the gas laws we have discussed so far:     ❒ We can combine all three expressions to form a single master equation for the behavior of gases:.     This Equation is called the ideal gas equation where R , the proportionality …

  preface of This book      The book is divided into four parts. The first part focuses on the macroscopic properties of physical systems. It begins with the descriptive study of gases and liquids, and proceeds to the study of thermodynamics, which is a comprehensive macroscopic theory of the behavior …

  preface of This book      Two very important fields of natural science—chemistry and the science of electricity— matured and grew vigorously during the first half of the nineteenth century. Electrochemistry developed simultaneously. From the very beginning, electrochemistry was not merely a peripheral field but evolved with an important …

Lewis Acids and Bases ❒ In 1923 G. N. Lewis proposed a theory that significantly broadened the understanding of acids and bases. ❒ As we go along we shall find that an understanding of Lewis acid– base theory is exceedingly helpful to understanding a variety of organic reactions. ❒ Lewis …

  The Volume-Amount Relationship: Avogadro’s Law ❒ The work of the Italian scientist Amedeo Avogadro complemented the studies of Boyle, Charles, and Gay-Lussac. ❒ In 1811 Avogadro published a hypothesis stating that at the same temperature and pressure, equal volumes of different gases contain the same number of molecules (or atoms …