Stoichiometry Questions and Answers(A+ Solution guide)

Subscript - A number in a chemical formula that tells the number of atoms in a molecule or the ratio of elements in a compound Law of conservation of mass - mass is neither created nor destroyed during ordinary chemical reactions or physical changes Mole ratio - fraction formed from the coefficients in a balanced chemical equation. Avogadro's Number - number of representative particles in a mole, 6.02 X 10^23 Products - The elements or compounds produced by a chemical reaction. On the right side of a chemical equation. Reactants - A starting material in a chemical reaction. On the left side of a chemical equation. Stoichiometry - (chemistry) expresses the quantitative relationship between reactants and products. Limiting reactant - the substance that is consumed completely - controls the quantity of product that can form in a chemical reaction. Can be determined by calculating the mass of a single product formed from each reactant. Excess reactant - The substance that is not used up completely in a reaction Molar Mass - The mass of 1 mole of any substance. Must use the periodic chart to obtain this value. units: g/molBalanced Chemical Equation - Allows one to determine the mole ratio of any two substances in the reaction 1st step in a stoichiometry problem - Write the "given" and what you "want" mass of one mole of a diatomic element (hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine) - twice the mass listed for that element on the periodic chart molar mass of a compound - the sum of the masses listed on the periodic chart of the atoms contained in it 2nd step in solving stoichiometry problem - travel the unit (what is says on the top, travels to bottom part in the picket fence) significant figures - a prescribed decimal place that determines the amount of rounding off to be done based on the precision of the measurement percent yield - the ratio of the actual yield to the theoretical yield expressed as a percent empirical formula - a formula with the lowest whole-number ratio of elements in a compound Coefficient - A number in front of a chemical formula in an equation that indicates how many molecules or atoms of each reactant and product are involved in a reaction.