# Chapter 3 – Chemical Reactions and the Earth’s Compositions

 Chemical Equation
 describes the identities and quantities of reactions (substances consumed) and products (substances formed)
 Mole(mol)
 of particles (atoms, ions, molecules) contains Avagadro’s number of the particles
 Molar Mass
 the mass of one mole of the particles that comprise their substance; the M of an element, in grams per mole, is numerically the same as the element’s average atomic mass, in amus
 Molecular Mass
 the mass of one molecule of a molecular compound
 Formula Mass
 of a compound is the mass of one formula unit
 Stoichmetry
 refers to the quantitive relation between the quantities of reactants and products in a chemical reaction
 Law of Conversation of Mass
 states that the sum of the masses of the reactants and products in a chemical reactions is the same
 Hydrolosis
 the reaction of water with another material
 Acid Anhydrides
 nonmetal oxides that react with water to produce acids
 Hydrocarbons
 molecular compounds composed of only hydrogen and carbon; are a class of organic compounds
 Combustion Reactions
 occur between oxygen and another element or compound; when the other is a hydrocarbon, the products of complete combustion are carbon dioxide and water vapor
 Percent Composition
 the percentage by mass of each element in a compound; it can also refer to the percentage by mass of each component in a mixture
 Empirical Formulas
 represent the proportions of the ions in the formula units
 Molecular Ion
 formed in a mass spectrometer when a neutral molecule loses an electron after being bombarded with a high-energy beam; it has a charge of 1+ and has essentially the same molecular mass as the neutral molecule from which it came
 Mass Spectrum
 a graph of the data from a mass spectrometer where m/2 ration of the deflected particles are plotted against the number of particles with a particular mass; because the charge on the ions typically is 1+, m/2 = m/1 = m and the mass of the particle may be read directly form the m/2 axis
 Combustion Analysis
 a substance is burned completely in oxygen to produce known compounds whose masses are used to determine the composition of the original material
 Limiting Reactant
 consumed completely in a chemical reaction; the amount of product formed depends on the amount of this available
 Theoretical Yield
 the amount of product expected for a chemical reaction given a specific quantity of reactant
 Actual Yield
 the amount of product obtained as a result of a chemical reaction conducted in a lab; often less than the theoretical yield