Ch. 4 chemical quantities nd aqueous reactions Flashcards
(26 cards)
Stoichiometry
the numberical relationship between chemical amounts in a balanced chemical equation. it allows us to predict the amounts of products that will form in a chemical reaction based on the amounts of reactants necessary to form a given amount of product. these calculations are central to chemistry, allowing chemists to plan and carry out chemical reactions to obtain products in the desired quantities.
Limiting reactant
the reactant that limits the amount of product in a chemical reaction. Notice that the limiting reactant is simply the reaction that makes the least amount of product. the reactant that do not limit the amount of product are said to be in excess.
Theoretical yield
the amount of product that can be made in a chemical reaction based on the amount of limiting reactant.
actual yield
the amount of product actually produced by a chemical reaction. ( the actual yield is always equal to or less than the theoretical yield because at least a small amount of product is usually lost to other reactions or does not form during a reaction. )
percent yield
the percentage of the theoretical yield that was actually attained. ACTUAL YIELD / THEORETICAL YIELD X 100%
Solution
a homogeneous mixture of 2 or more substances (such as salt and water) is called a solution.
Solvent
the majority component of a solution is the solvent.
Solute
the minority component.
Aqueous solution
a solution in which water acts as the solvent ( the majority)
dilute solution
a solution that contains a small amount of solute relative to the solvent.
concentrated solution
one that contains a large amount of solute relative to the solvent.
molarity (M)
the amount of solute (in moles) / (divided by) the volume of solution (in liters)
Electrolytes
substances that dissolved in water to form solutions that conduct electricity.
Strong electrolytes
Substances such as sodium chloride that completely dissociate into ions when they dissolve in water, this results in solutions that are strong electolyte solutions.
Nonelectrolytes
compounds such as sugar that do not dissociate into ions when dissolved in water, they DO NOT conduct electricity.
Acids
molecular compounds that ionize (form ions) when they dissolve in water. for example, HCl, a molecular compound that ionizes into H+ and Cl- when it dissolves in water.
Strong Acid
an acid that completely ionizes in solution. since they completely ionize in solution, strong acids are also strong electrolytes. this is represented by a single reaction arrow b etween the acid and its ionized form. HCl (aq) —-> H+ (aq)+ Cl-(aq)
weak acids
those that do not completely ionize in water. for example acetic acid (HC2H3O2) the acid present in vinegar, is a weak acid. a solutionof a weak acid is composed mostly of the nonionized acid- only a small percentage of the acid molecules ionize. we represent the partial ionization of a weak acid with opposing half arrows between the reacts and the products ….. ——-> …….. <——-
molecular equation
a chemical equation showing the complete, neutral formulas for every compound in a reaction
complete ionic equation
a chemical equation showing all of the species as they are actually present in solution
net ionic equation
an equation showing only the species that actually change during the reaction.
Acid base reaction
aka neutralization reaction. an acid reacts with a base and the 2 neutralize each other, producing water (or in some cases a weak electrolyte).
Gas evolution Reaction
a gas forms, resulting in bubbling. in both cases, as in precipitation reactions, the reactions occur when the anion from one reactant combines with the cation of the other. In addition, many has evolution reactions are also acid base reactions.
what do acids produce?
acid substance that produces H+ ions in aqueous solution
