AP CHEM - Unit 4 Vocab

Physical Change/Process

changes in states, or changes that do not result in new matter

Chemical Change/Process

one or more substances (the reactants) change into one or more new substances (the products)

Synthesis

a chemical change in which two or more substances react to form a single new substance. 

A+B -> AB

Decomposition

a chemical change in which a single compound breaks down into two or more simpler products

AB -> A + B

Single Replacement

a chemical change in which one element replaces a second element in a compound.

AB + C -> AC+ B

Double Replacement

a double displacement reaction is a chemical change involving an exchange of positive ions between two compounds. (Generally takes place in aqueous solution and often produces a precipitate, a gas, or a molecular compound such as water)

AB + CD → AD + CB

Combustion

A combustion reaction is a chemical change in which a hydrocarbon reacts with oxygen often producing energy in the form of heat and light.

(Complete combustion – a hydrocarbon reacts with oxygen gas to form carbon dioxide and water vapor)

Acid/Base Neutralization

reaction between an acid and a base resulting in the formation of a salt and water

ACID + BASE → Salt + H₂O

Precipitation Reaction

a chemical reaction where two or more soluble ionic compounds react to form a precipitate

Oxidation/Reduction Reaction

a chemical reaction involving the transfer of electrons between two reactants

Oxidation

the loss of electrons, which increases the oxidation state

Reduction

the gain of electrons, which decreases the oxidation state

Oxidation numbers

hypothetical charges an atom would have if all its bonds were fully ionic, indicating how many electrons an atom has gained or lost to form a chemical bond

Net Ionic Reaction

shows only the species that are directly involved in a chemical change, excluding "spectator ions" that remain unchanged on both sides of the equation

Complete Ionic Reactions

a chemical equation that shows all soluble ionic compounds as separate, dissociated ions in an aqueous solution

Spectator Ions

ions that are not involved in the chemical reaction

“SNAP”

A specific chemical compound, S-nitroso-N-acetylpenicillamine, and a general class of compounds that donate nitric oxide (NO)

Stoichiometry

the quantitative study of reactants and products in chemical reactions, using balanced chemical equations to determine the numerical relationships between them

Mole Ratio

the ratio between the amounts in moles of any two substances involved in a balanced chemical reaction, determined by the coefficients in the balanced equation

Limiting Reactant

the substance that is completely consumed first in a chemical reaction and determines the maximum amount of product that can be formed

Excess Reactant

a reactant present in a greater-than-needed amount that remains unreacted after a chemical reaction is complete

Percent Yield

a measure of a chemical reaction's efficiency

Formula: (Actual Yield / Theoretical Yield) x 100

Theoretical Yield

the maximum amount of product you should get, based on calculations

Actual Yield

the amount of product you actually get in a lab

Bronsted-Lowry Acid/Base Reactions

a proton (𝐻+) transfer where an acid donates a proton to a base, which accepts it. The reaction forms a conjugate base and a conjugate aci

Acids

a chemical substance that produces hydrogen ions (𝐻+) when dissolved in water

(0-6 on the pH scale)

Bases

A substance that can accept hydrogen ions or, in water, release hydroxide ions (𝑂𝐻−)

(8-14 on the pH scale)

Conjugate Acids

the species that results from the addition of a proton to a base

Conjugate Bases

the species that remains after an acid has donated a proton (𝐻+)

Conjugate Pairs

a pair of chemical species that differ by only a single proton (𝐻+)

Titrations

a laboratory method used to determine the unknown concentration of a solution by carefully adding a second solution of known concentration until the reaction is complete, often signaled by a color change

Titrant

solution of a precisely known concentration that is slowly added to an unknown solution (the analyte) during a titration until the reaction is complete

Analyte

the specific substance or chemical constituent that is the subject of an analysis which is being identified and quantified in a sample

Equivalence Point

point when all of the acid and base have been neutralized

Dissolve

to cause a solute (the substance being dissolved) to disperse into a solvent (the dissolving medium) to form a homogeneous solution

Dissociate

For ionic compounds, this means separating into individual ions

Dissolution

a chemical process where a solute dissolves in a solvent to form a homogeneous mixture called a solution

Redox Reaction

a type of chemical reaction where electrons are transferred between substances

End point

the point at which the indicator changes color