The enormous variety of biological, chemical, and physical properties of matter result from the ability of atoms to form bonds. This ability results from the electrostatic forces between electrons and protons and between atoms and molecules. The conservation of atoms in chemical reactions leads to the principle of conservation of matter and the ability to calculate the mass of products and reactants. The Kinetic Molecular theory describes the motion of atoms and molecules and explains the properties of gases. Acids, bases, and salts are three classes of compounds that form ions in water solutions.
Solutions are homogenous mixtures of two or more substances.
Energy is exchanged or transformed in all chemical reactions and physical changes of matter. Energy is released when a material condenses or freezes and absorbed when a material evaporates or melts. Chemical reaction rates depend on factors that influence the frequency of collision of reactant molecules. Chemical equilibrium is a dynamic process at the molecular level. Equilibrium is established when forward and reverse reaction rates are equal.