All Flashcards
What is a chemical reaction?
Rearrangement of atoms and molecules to form new substances; bonds are broken and new bonds are formed.
Define a synthesis reaction.
Simpler substances combine to form a more complex one. A + B → AB
Define a decomposition reaction.
A complex substance breaks down into simpler ones. AB → A + B
What is a net ionic equation?
An equation that shows only the species that are actively involved in the reaction, omitting spectator ions.
What are spectator ions?
Ions that do not participate in a chemical reaction and are not included in the net ionic equation.
Define Stoichiometry.
The math of chemical reactions; quantifies the amounts of reactants and products in a reaction.
What is a limiting reactant?
The reactant that runs out first, limiting the amount of product formed.
Define Oxidation.
Loss of electrons (oxidation number increases).
Define Reduction.
Gain of electrons (oxidation number decreases).
What is a conjugate base?
The species formed when an acid donates a proton.
What are the steps to write net ionic equations?
- Write the balanced molecular equation. 2. Dissociate all aqueous compounds into ions. 3. Identify and cancel out spectator ions. 4. Write the final net ionic equation with only the reacting species.
What are the steps to balance chemical equations?
- Write out the unbalanced equation. 2. Start by balancing elements that appear in only one compound on each side. 3. Balance polyatomic ions as a single unit if they appear unchanged on both sides. 4. Balance hydrogen and oxygen last. 5. Double-check that all atoms and charges are balanced.
How to assign oxidation numbers?
- Elemental form = 0. 2. Monatomic ion = charge. 3. Oxygen = -2 (except in peroxides). 4. Hydrogen = +1 (except with metals). 5. Sum = 0 (neutral compound) or charge (polyatomic ion).
What are the differences between physical and chemical changes?
Physical: Changes in intermolecular forces, no change in composition (e.g., melting ice). Chemical: Changes in intramolecular bonds, new substances formed (e.g., burning wood).
What are the differences between acids and bases according to the Brønsted-Lowry definition?
Acids: Proton (H⁺) donors. Bases: Proton (H⁺) acceptors.
What are the differences between Oxidation and Reduction?
Oxidation: Loss of electrons (oxidation number increases). Reduction: Gain of electrons (oxidation number decreases).
What is the difference between endpoint and equivalence point?
Endpoint: The point in a titration where a color change is observed, usually indicated by an indicator. Equivalence Point: The point where the moles of titrant added are equal to the moles of analyte.