SAS 5-9

• chemical reactions involve breaking bonds in the reactants and forming new bonds in the product
• a chemical equation uses chemical formulas and other symbols showing what reactants are used as the starting materials in a reaction and what products are formed
• the reactants are written on the left
• the products are written to the right
• coefficients show the number of molecules of a given element or compound that react or are formed
• the law of conservation of mass states that atoms cannot be created or destroyed in a chemical reaction
• a balanced equation has the same number of atoms of each element on both sides of the equation
• a mole is a quantity that contains 6.02 x 10^23 items
• the formula weight is the sum of the atomic weights of all the atoms in a compound, reported in atomic mass units (amu)
• the molar mass is the mas of one mole of any substance, reported in grams
• Use the mole ratios from the coefficients in the balanced equation to convert moles of one compound (A) into moles of another compound (B)
• The theoretical yield is the amount of product expected from a given amount of reactant based on the coefficients in the balanced chemical equation
• The actual yield is the amount of product isolated from a reaction
• • The limiting reactant is the reactant that is completely used up in a reaction
• Oxidation is the loss of electrons from an atom
• reduction is the gain of electrons by an atom
• a redox reaction involves the transfer of electrons from one element to another. always has two components, oxidation and reduction
• boyle's law for a ixed amount of gas at constant temperature, the pressure and volume of the gas are inversely related
• charle's law for a fixed amount of at constant pressure, the volume of the gas is proportional to its kelvin temperature
• gay-lussac's law for a fixed amount of gas at constant volume, the pressure of a gas is proportional to its kelvin temperature
• avogadro's law when the pressure and temperature are held constant, the volume of a gas is proportional the number of moles present
• standard conditions of temperature and pressure abbreviated as stp
• all all four properties of gas (i.e., P, V, n, and T)can becombined into a single equation called the ideal gas law
• dalton's law the total pressure of a gas mixture is the sum of the partial pressures of its component gases
• intermolecular forces are the attractive forces that exist between molecules
• london dispersion forces are very weak interactions due to the momentary changes in electron density in a molecule
• dipole-dipole interactions are the attractive forces between the permanent dipoles of two polar molecules
• hydrogen bonding occurs when a hydrogen atom bonded to O, N, or F is electrostatically attracted to an O, N, or F atom in another molecule
• hydrogen bonds are the strongest of the three types of intermolecular forces
• boiling point is the temperature at which a liquid is converted to the gas phase
• melting point is the temperature at which a solid is converted to the liquid phase
• evaporation is the conversion of liquids into the gas phase
• evaporation is endothermic it absorbs heat from the surroundings
• condensation is the conversion of gases into the liquid phase
• condensation is exothermic- it gives off heat to the surroundings
• vapor pressure is the pressure exerted by gas molecules in equilibrium with the liquid phase
• viscosity is a measure of a fluids resistance to flow freely
• surface tension is a measure of the resistance of a liquid to spread out
• interior molecules in a liquid are surrounded by intermolecular forces on all sides
• surface molecules only experience intermolecular forces from the sides and from below