Chemical Changes, Acids, Bases, and Reaction Types

Vocabulary flashcards covering indicators of chemical reactions, physical and chemical changes, properties of acids, bases, and salts, pH, and fundamental types of chemical reactions.

Formation of a Precipitate

An insoluble solid formed during a chemical reaction, such as white silver chloride formed from combining colorless silver solutions.

Effervescence

Spontaneous bubbling or gas production during a chemical reaction.

Reversible change

A change that can be undone.

Irreversible change

A change that cannot easily be undone.

Physical change

A change in which no new substance is formed, changing appearance or state only, usually reversible, where the original material remains the same.

Chemical change

A change in which new substances are formed, changing the material's composition, usually irreversible, where the original material changes into something new.

Acids

Substances that dissociate to produce $H^+$ ions in water, donate hydrogen ions ($H^+$) in water, or act as proton donors. Common properties include a $pH < 7$, reacting with metals, conducting electricity in solution, and having a sour taste.

Bases

Substances that produce hydroxide ions ($OH^-$) in water or accept $H^+$. Common properties include a bitter taste, slippery feel, $pH > 7$, and neutralizing acids.

Salts

All ionic compounds composed of cations other than $H^+$ and anions other than $O^-$ (oxide anion) or $OH^-$ (hydroxide anion). Common properties include being crystalline solids, odorless, having high melting and boiling points, acting as electrolytes, and stability.

pH ("power of hydrogen")

A quantitative measure of the acidity and basicity of liquids or aqueous solutions, where $pH < 7$ is acidic, $pH = 7$ is neutral (pure water), and $pH > 7$ is alkaline/basic.

Decomposition

A reaction where a single compound breaks down into two or more simpler substances.

Combination

A reaction where two or more simple substances combine to form one complex structure.

Single displacement

A reaction where a more reactive element replaces a less reactive element in a compound.

Double displacement

A reaction where two compounds exchange ions to form two new compounds.