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Chemistry LibreTexts

4: Water

  • Page ID
    206552
    • 4.1: The Uniqueness of Water
      Water is everywhere!
    • 4.2: Why is water a liquid at room temperature?
      Covalent bonds can be nonpolar or polar, depending on the electronegativities of the atoms involved. Covalent bonds can be broken if energy is added to a molecule. The formation of covalent bonds is accompanied by energy given off. Covalent bond energies can be used to estimate the enthalpy changes of chemical reactions.
    • 4.3: What makes molecules stick together? -- Intermolecular Forces
      All substances experience dispersion forces between their particles. Substances that are polar experience dipole-dipole interactions. Substances with covalent bonds between an H atom and N, O, or F atoms experience hydrogen bonding. The preferred phase of a substance depends on the strength of the intermolecular force and the energy of the particles.
    • 4.4: Electron Transfer - Ionic Bonds
      The tendency to form species that have eight electrons in the valence shell is called the octet rule. The attraction of oppositely charged ions caused by electron transfer is called an ionic bond. The strength of ionic bonding depends on the magnitude of the charges and the sizes of the ions.
    • 4.5: Writing Formulas for Ionic Compounds
      Formulas for ionic compounds contain the symbols and number of each atom present in a compound in the lowest whole number ratio.
    • 4.6: Naming Ionic Compounds
      Ionic compounds are named by stating the cation first, followed by the anion. Positive and negative charges must balance. Some anions have multiple forms and are named accordingly with the use of roman numerals in parenthes. Ternary compounds are composed of three or more elements.
    • 4.7: Defining terms associated with solutions
      Solutions are composed of a solvent (major component) and a solute (minor component). Concentration is the expression of the amount of solute in a given amount of solvent and can be described by several qualitative terms. Solubility is a specific amount of solute that can dissolve in a given amount of solvent. "Like dissolves like" is a useful rule for deciding if a solute will be soluble in a solvent.
    • 4.8: What is a solution?
      A solution is a homogeneous mixture-a mixture of two or more substances that are so intimately mixed that the mixture behaves in many ways like a single substance. Many chemical reactions occur when the reactants are dissolved in solution. In this chapter, we will introduce concepts that are applicable to solutions and the chemical reactions that occur in them.
    • 4.9: Aqueous Solutions and Solubility - Compounds Dissolved in Water
      When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them. This process represents a physical change known as dissociation. Under most conditions, ionic compounds will dissociate nearly completely when dissolved, and so they are classified as strong electrolytes.
    • 4.10: Quantitative Units of Concentration
      Quantitative units of concentration include molarity, molality, mass percentage, parts per thousand, parts per million, and parts per billion.
    • 4.11: Concentrations as Conversion Factors
      Know how to apply concentration units as conversion factors.
    • 4.12: Dilutions and Concentrations
      Calculate the new concentration or volume for a dilution or concentration of a solution.
    • 4.13: Types of Chemical Reactions - Single and Double Replacement Reactions
      A single-replacement reaction replaces one element for another in a compound. The periodic table or an activity series can help predict whether single-replacement reactions occur. A double-replacement reaction exchanges the cations (or the anions) of two ionic compounds. A precipitation reaction is a double-replacement reaction in which one product is a solid precipitate. Solubility rules are used to predict whether some double-replacement reactions will occur.
    • 4.14: Precipitation Reactions
      A precipitation reaction is a reaction that yields an insoluble product—a precipitate—when two solutions are mixed. Thus precipitation reactions are a subclass of exchange reactions that occur between ionic compounds when one of the products is insoluble. Because both components of each compound change partners, such reactions are sometimes called double-displacement reactions.
    • 4.15: Arrhenius Acids and Bases
      An Arrhenius acid is a compound that increases the H+ ion concentration in aqueous solution. An Arrhenius base is a compound that increases the OH− ion concentration in aqueous solution. The reaction between an Arrhenius acid and an Arrhenius base is called neutralization and results in the formation of water and a salt.
    • 4.16: Reactions of Acids and Bases
      When an acid and a base are combined, water and a salt are the products. Salts are ionic compounds containing a positive ion other than H+ and a negative ion other than the hydroxide ion, OH-. Double displacement reactions of this type are called neutralization reactions. Salt solutions do not always have a pH of 7, however. Through a process known as hydrolysis, the ions produced when an acid and base combine may react with the water to produce slightly acidic or basic solutions.
    • 4.17: The pH Scale
      pH is a logarithmic function of [H+]. [H+] can be calculated directly from pH. pOH is related to pH and can be easily calculated from pH.
    • 4.E: Solutions (Exercises)