CoreChem:Reactions in Aqueous Solutions

From ChemPRIME

1. Introduction: The Ambit of Chemistry

What Chemists Do Handling Large and Small Numbers The International System of Units (SI) SI Prefixes Measurements, Quantities, and Unity Factors Errors in Measurement Volume Density Conversion Factors and Functions

2. Atoms, Molecules, and Chemical Reactions

Macroscopic Properties and Microscopic Models The Atomic Theory Macroscopic and Microscopic Views of a Chemical Reaction Testing the Atomic Theory Atomic Weights The Amount of Substance: Moles The Mole The Amount of Substance The Avogadro Constant The Molar Mass Formulas and Composition Balancing Chemical Equations

3. Using Chemical Equations in Calculations

Equations and Mass Relationships The Limiting Reagent Percent Yield Analysis of Compounds Thermochemistry Energy Thermochemical Equations Hess' Law Standard Enthalpies of Formation Solution Concentrations Diluting and Mixing Solutions Titrations

4. The Structure of Atoms

Groups of Related Elements The Periodic Table Valence Exceptions to the Periodic Law Implications of Periodicity for Atomic Theory The Nuclear Atom Radiation The Electron The Nucleus Atomic Structure and Isotopes Isotopes Transmutation and Radioactivity Average Atomic Weights Measurement of Atomic Weights

5. The Electronic Structure of Atoms

Electrons and Valence Lewis Diagrams The Wave Nature of the Electron Wave Mechanics The Uncertainty Principle Electron Waves in the Hydrogen Atom Orbitals Quantum Numbers Coulomb’s Law Potential Energy Electron Density and Potential Energy Atoms Having More Than One Electron Hydrogen, Helium, Lithium Beryllium, Boron, Carbon Electron Configurations Electron Configurations and the Periodic Table

6. Chemical Bonding - Electron Pairs and Octets

7. Further Aspects of Covalent Bonding

Exceptions to the Octet Rule The Shapes of Molecules Molecules with Lone Pairs Multiple Bonds and Molecular Shapes Hybrid Orbitals Orbital Descriptions of Multiple Bonds Sigma and Pi Bonds Polarizability Polar Covalent Bonds Electronegativity Polarity in Polyatomic Molecules Formal Charge and Oxidation Numbers Resonance

8. Properties of Organic Compounds ...

9. Gases

10. Solids, Liquids and Solutions

11. Reactions in Aqueous Solutions

12. Chemistry of the Representative Elements

Group IA: Alkali Metals Group IIA: Alkaline Earths Group IIIA Group IVA Group VA Group VIA: Chalcogens Group VIIA: Halogens Group VIIIA: Noble Gases

13. Chemical Equilibrium

The Equilibrium State The Equilibrium Constant The Law of Chemical Equilibrium The Equilibrium Constant in Terms of Pressure Calculating the Extent of a Reaction Successive Approximation Predicting the Direction of a Reaction Le Chatelier’s Principle The Effect of a Change in Pressure The Effect of a Change in Temperature Effect of Adding a Reactant or Product The Molecular View of Equilibrium

14. Ionic Equilibria in Aqueous Solutions

Ionization of Water pH and pOH The pH of Solutions of Weak Acids The pH of Solutions of Weak Bases Polyprotic Acids and Bases Conjugate Acid-Base Pairs and pH Buffer Solutions Indicators Titration Curves The Solubility Product The Common-Ion Effect The Solubilities of Salts of Weak Acids

15. Thermodynamics: Atoms, Molecules and Energy

Heat Capacities Heat Capacity and Microscopic Changes Internal Energy Thermodynamic Terms and Conventions Enthalpy Measuring the Enthalpy Change State Functions Standard Pressure Bond Enthalpies Bond Enthalpies and Exothermic or Endothermic Reactions Fossil Fuels and the Energy Crisis Photosynthesis

16. Entropy and Spontaneous Reactions

17. Electrochemical Cells

Electrolysis Electrolysis of Brine Aluminum Production Refining of Copper Electroplating Quantitative Aspects of Electrolysis Galvanic Cells Cell Notation and Conventions Electromotive Force of Galvanic Cells Storage Batteries Fuel Cells Galvanic Cells and Free Energy Cells at Non-Standard Conditions

18. Chemical Kinetics

The Rate of Reaction The Rate Equation Microscopic View of Chemical Reactions Unimolecular Processes Bimolecular Processes Termolecular Processes Reaction Mechanisms Increasing the Rate of a Reaction The Effect of Temperature Catalysis Heterogeneous Catalysis

19. Nuclear Chemistry

Naturally Occurring Radioactivity Radioactive Series Artificially Induced Nuclear Reactions Bombardment with Positive Ions Neutron Bombardment Further Modes of Decay Nuclear Stability The Rate of Radioactive Decay Instruments for Radiation Detection Units of Radiation Dose Uses of Artificial Isotopes Mass-Energy Relationships Nuclear Fission Nuclear Power Plants Breeder Reactors Nuclear Fusion

20. Molecules in Living Systems

21. Spectra and Structure of Atoms and Molecules

The Nature of Electromagnetic Radiation Atomic Spectra and the Bohr Theory Bohr Theory of the Atom The Spectra of Molecules: Infrared The Visible and Ultraviolet Spectra of Molecules: Molecular Orbitals Molecular Orbitals Delocalized Electrons Conjugated Systems

22. Metals

Metallic Bonding Metallurgy Beneficiation Reduction of Metals Refining of Metals Corrosion Coordination Compounds Geometry of Complexes Chelating Agents Transitional Metal Ions in Aqueous Solutions

In other sections we emphasized the importance of liquid solutions as a medium for chemical reactions. Water is by far the most important liquid solvent, partly because it is plentiful and partly because of its unique properties. In your body, in other living systems, and in the outside environment a tremendous number of reactions take place in aqueous solutions. Consequently this section, as well as significant portions of many subsequent sections, will be devoted to developing an understanding of reactions which occur in water. Since ionic compounds and polar covalent compounds constitute the main classes which are appreciably soluble in water, reactions in aqueous solutions usually involve these types of substances.

Reactions in aqueous solutions usually involve ionic or polar covalent compounds. The solubilities of such compounds are enhanced because of their interactions with water molecules, especially the hydration of ions. Measurement of the electrical current conducted by a solution of known concentration enables us to determine whether a solute is an electrolyte, and, if so, of what type. Water itself is an extremely weak electrolyte, producing hydronium ions and hydroxide ions, each at a concentration of 1.00 × 10^–7 mol dm^–3 at 25°C.

There are three important classes of reactions which occur in aqueous solution: precipitation reactions, acid-base reactions, and redox reactions. Whether or not a precipitate will form when solutions of about 0.1 M concentration are mixed can be predicted using the solubility rules. Precipitation reactions are useful for detecting the presence of various ions and for determining the concentrations of solutions.

Acid-base reactions and redox reactions are similar in that something is being transferred from one species to another. Acid-base reactions involve proton transfers, while redox reactions involve electron transfers. Redox reactions are somewhat more complicated, though, because proton transfers and other bond-making and bond-breaking processes occur at the same time as electron transfer. Both proton transfer and electron transfer can be broken into half-equations: one to describe donation of a proton (or electrons), and one to describe acceptance of a proton (or electrons). For acid-base reactions, each half-equation involves a conjugate acid-base pair. For oxidation-reduction reactions, each half-equation involves a redox couple.

Both conjugate acid-base pairs and redox couples may be tabulated in order of acidic strength, basic strength, oxidizing power and reducing power. Such behavior is also quantified in terms of acid constants, base constants and reduction potentials. In each case such tabulations may be used to determine whether a given reaction will go to completion, occur only to a limited extent, or not occur at all.

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CoreChem:Reactions in Aqueous Solutions

From ChemPRIME

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