GEN CHEM 1 Midterm 2 (CHP 4-6 Part 1)

Comprehensive vocabulary flashcards covering chemical equations, stoichiometry, limiting reactants, solution concentrations, types of aqueous reactions, acid-base theories, and redox processes from Chapters 4 and 5.

Chemical Reaction

A process in which one or more substances are converted into new substances, commonly evidenced by color change, precipitate formation, gas evolution, or the evolution/absorption of heat.

Chemical Equation

A symbolic way of representing a chemical reaction in which formulas for the reactants and products are written on the left and right sides of the equation, respectively.

Stoichiometry

The quantitative measuring and inter-relating of substances in a balanced chemical reaction, derived from the Greek words stoicheion ("element") and metron ("measure").

Stoichiometric Coefficient

A coefficient required to balance a chemical reaction (often denoted by the Greek letter $\nu$ ("nu")), essential for relating molar amounts of reactants consumed and products formed.

Stoichiometric Factor

A central conversion factor (mole ratio) derived from stoichiometric coefficients that relates the molar amounts of two species in a balanced chemical reaction.

Stoichiometric Proportions

The condition occurring when all reactants are completely and simultaneously consumed in a chemical reaction.

Limiting Reagent (Limiting Reactant)

A reactant present in a substoichiometric amount that is completely converted into products while other reactants remain in excess, thereby determining the maximum yield of product.

Solvent

A substance that dissolves another substance (the solute) to form a solution, typically present as the major constituent (largest amount) in the mixture.

Solute

A minor constituent substance that is dissolved in a solvent to create a solution.

Molarity ($M$)

A measure of concentration defined as the number of moles of solute per total liters of solution ($M = \frac{n}{V}$), with units of $\text{mol/L}$ (symbol $C$ is recommended by IUPAC).

Dilution

The process of reducing solute concentration by transferring a fixed amount of moles of solute from a smaller volume to a larger volume, governed by $M_i V_i = M_f V_f$.

Theoretical Yield

The maximum quantity of product predicted to form by the balanced chemical equation assuming 100% conversion of the limiting reactant.

Percent Yield

A measure of reaction efficiency expressed as the ratio of actual yield to theoretical yield: $\text{\% Yield} = \frac{\text{actual yield}}{\text{theoretical yield}} \times 100$.

Quantitative Reaction

A reaction in which the actual yield almost exactly equals the predicted theoretical yield.

Simultaneous Reactions

Reactions in which two or more substances react independently of one another in separate reactions occurring at the same time.

Consecutive Reactions

A reaction sequence carried out one step after another to yield a final product.

Intermediate

A substance produced in one step of a multistep reaction sequence and subsequently consumed in a later step.

Overall Reaction

A single combined equation representing the sum of a series of consecutive reactions after matching molar coefficients and canceling out all intermediates.

Extent of Reaction ($\xi$)

A quantitative measure of how far a reaction has proceeded, defined as $\xi = \frac{\Delta n_k}{\nu_k}$, where $\nu_k$ is the stoichiometric number (negative for reactants, positive for products).

Solvation (Hydration)

The process in which solid ionic compounds break up (dissociate) into individual ions surrounded by solvent (water) molecules when placed in a liquid.

Strong Electrolyte

A substance that dissolves well in water and dissociates/ionizes almost completely into ions (degree of dissociation $\approx 100\%$), conducting electricity strongly.

Weak Electrolyte

A molecular compound that ionizes only incompletely in aqueous solution (degree of dissociation $< 10\%$), yielding a poorly conducting solution.

Nonelectrolyte

A molecular substance (such as methanol, $\text{CH}_3\text{OH}$) that dissolves in water without significant dissociation into ions and whose solution does not conduct electricity.

Arrhenius Acid

A substance that produces hydrogen ions ($\text{H}^+(aq)$) when dissolved in aqueous solution.

Arrhenius Base

A substance that produces hydroxide ions ($\text{OH}^-(aq)$) when dissolved in aqueous solution.

Brønsted-Lowry Acid

A chemical species that donates a proton ($\text{H}^+$) to another species.

Brønsted-Lowry Base

A chemical species that accepts a proton ($\text{H}^+$), requiring an available lone pair of electrons.

Amphoteric Species

A molecule or ion that can act as either an acid or a base depending on the chemical environment (e.g., $\text{H}_2\text{O}$).

Precipitate

An insoluble ionic solid formed when specific cations and anions combine in an aqueous solution.

Spectator Ion

An ion present in a reaction mixture that does not participate directly in the chemical change and remains unchanged on both sides of the complete ionic equation.

Net Ionic Equation

A chemical equation written by ionizing strong electrolytes and canceling spectator ions to show only the species directly involved in the reaction.

Neutralization Reaction

A reaction between an acid and a base that produces an ionic compound (a salt) and water, characterized by $\text{H}^+$ changing partners.

Oxidation

A process defined by an increase in the oxidation state (oxidation number) of an element ($\text{Ox.\#}\uparrow$).

Reduction

A process defined by a decrease in the oxidation state (oxidation number) of an element ($\text{Ox.\#}\downarrow$).

Redox Reaction

A chemical reaction in which the oxidation states of reactant atoms change, requiring an oxidation to always be paired with a corresponding reduction.