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chemical reaction
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process that neither creates nor destroys atoms, but that rearranges atoms in chemical compounds. involve changes in energy.
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chemical equation
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uses chemical symbols to denote what occurs in a chemical reaction.
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a chemical equation represents a chemical statement.
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reactant
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each chemical species that appears to the left of the arrow.
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substances that are consumed in the course of a chemical reaction.
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product
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each species that appears to the right of the arrow.
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substances that form during the course of a chemical reaction.
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gases, liquids, and solids are labeled with (g), (l), and (s).
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aqueous: chemical species that are dissolved in water; labeled (aq)
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some nonmetals exist as polyatomic molecules: H2, N2, O2, F2, Cl2, Br2, I2, and P4.
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law of conservation of mass
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atoms can neither be created nor destroyed.
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stoichiometric coefficients
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numeric values written to the left of each species in a chemical equation to balance the equation.
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stoichiometric amount
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quantity of reactant in the same relative amount as that represented in the balanced chemical equation.
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limiting reactant
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reactant used up first in a reaction, limits the amount of product that can form.
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excess reactant
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present in quantities greater than necessary to react with the quantity of the limiting reactant.
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theoretical yield
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amount of product that forms when all the limiting reactant reacts to form the desired product; maximum obtainable yield, predicted by the balanced equation (the limiting reactant produces the theoretical yield).
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actual yield
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amount of product actually obtained from a reaction; almost always less than the theoretical yeild.
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percent yield
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determines the efficiency of a chemical reaction
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% yield = actual yield/theoretical yield (100%)
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temperature and pressure can affect percent yield.
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atom economy
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theoretical determination of how much of the starting mass of reactants can end up in the final mass of the desired product.
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atom economy = sum of molar mass of desired product/sum of molar masses of reactants (100%)
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combination reaction
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two or more reactants combine to form a single product - A + B --> AB
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decomposition reaction
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two or more products form a single reactant; opposite of combination reaction - AB --> A + B
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combustion reaction
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substance burns in the presence of oxygen. produces carbon dioxide gas and water.
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combustion analysis
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experimental determination of an empirical formula by a reaction with oxygen to produce carbon dioxide and water.
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organic compounds
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containing C, H, and O, are carried out using an apparatus in combustion analysis.
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Cheatography n. The art of mapping complex subjects into clear, instantly navigable reference guides.
