Chemistry Exam

Acids

Produce H⁺ (or H₃O⁺) in water.

Bases

Produce OH⁻ in water.

Arrhenius acid

A substance that produces H⁺ ions when dissolved in water.

Arrhenius base

A substance that produces OH⁻ ions when dissolved in water.

Recognizing Arrhenius acids

Look for formulas starting with H (e.g., HCl, HNO₃).

Recognizing Arrhenius bases

Look for metal cations paired with OH⁻ (e.g., NaOH, Ca(OH)₂).

Brønsted-Lowry acid

A proton (H⁺) donor.

Brønsted-Lowry base

A proton (H⁺) acceptor.

Identifying Brønsted-Lowry acids and bases

Compare reactants/products: whichever loses H⁺ is the acid; whichever gains H⁺ is the base.

Conjugate acid-base pair

Two species that differ by exactly one proton (H⁺).

Strength relation: strong acid vs conjugate base

The stronger the acid, the weaker its conjugate base.

Strength relation: weak acid vs conjugate base

The weaker the acid, the stronger its conjugate base.

Amphiprotic/amphoteric substance

A substance that can both donate AND accept H⁺ (e.g., water, HCO₃⁻).

Recognizing amphiprotic substances

Look for species with both a removable H and a negative charge.

Autoionization of water

Water forms H₃O⁺ and OH⁻ on its own, showing it acts as both acid and base.

Binary acids: trends

Acid strength increases down a group (bond strength decreases); increases with higher bond polarity.

Binary acids: leveling effect

In water, all strong acids completely ionize and appear equally strong (leveled).

Ternary acids trends (same central atom)

Acid strength increases as the oxidation state of the central atom increases and as more oxygen atoms are present.

Ternary acids trends (same group different elements)

Acid strength increases with electronegativity of the central atom.

Neutralization reaction

A reaction between an acid and a base that produces water and a salt.

Neutralization: strong acid + strong base

Complete ionization on both sides; net ionic equation: H⁺ + OH⁻ → H₂O.

Neutralization: weak acid + strong base

Weak acid partially ionizes; conjugate base forms.

Neutralization: strong acid + weak base

Weak base only partially accepts protons; conjugate acid forms.

Neutralization: weak acid + weak base

Equilibrium reaction; products depend on relative strengths.

Normal salt

Formed from complete neutralization of acid and base.

Acidic salt

Forms when a polyprotic acid is only partially neutralized.

Basic salt

Forms when a polyhydroxy base is only partially neutralized.

Lewis acid

An electron-pair acceptor.

Lewis base

An electron-pair donor.

Coordinate covalent bond formation

A bond formed when both electrons come from the Lewis base.

Recognizing Lewis acids

Look for electron-deficient atoms, metal cations, or species with incomplete octets.

Recognizing Lewis bases

Look for lone pairs or negative charges.

Preparing acids (general methods)

Commonly by dissolving nonmetal oxides in water (e.g., SO₃ + H₂O → H₂SO₄).

Molarity (definition)

Moles of solute per liter of solution.

Limiting reactant review

The reactant that is entirely consumed first and limits the amount of product formed.

Acid-base stoichiometry

Use mole ratios from balanced equations to find required volumes or moles.

Titration (definition)

A technique where a solution of known concentration is used to determine the concentration of an unknown.

Indicator (definition)

A substance that changes color at or near the equivalence point.

Burette (definition)

A device used to deliver measured volumes in a titration.

Equivalence point (definition)

Point where moles of acid = moles of base.

End point (definition)

The point where the indicator changes color.

Primary standard properties

High purity, stable, non-hygroscopic, large molar mass.

Standardized solution (secondary standard)

A solution whose concentration is determined through titration with a primary standard.

Percent yield (in titration problems)

(Actual amount ÷ theoretical amount) × 100%.

Balancing redox equations

Use oxidation numbers; balance electrons using half-reactions.

Redox titration calculations

Similar to acid-base titrations but focus on electron transfer.

Gas properties

Gases expand to fill containers, are compressible, and have low density.

Pressure (definition)

Force exerted per unit area.

Boyle's Law

P₁V₁ = P₂V₂ (inverse relationship).

Charles's Law

V₁/T₁ = V₂/T₂ (direct relationship).

Combined Gas Law

(P₁V₁)/T₁ = (P₂V₂)/T₂.

Standard Temperature and Pressure (STP)

0°C and 1 atm; molar volume is 22.4 L/mol.

Avogadro's Law

V ∝ n; equal volumes of gas at same T and P contain same number of moles.

Ideal Gas Law

PV = nRT.

Molecular weight via gases

Use density or ideal gas law to find molar mass (MM = dRT/P).

Dalton's Law of Partial Pressures

Total pressure = sum of partial pressures.

Mole fraction (definition)

Moles of component ÷ total moles.

Gas collected over water

Correct pressure: P(gas) = P(total) - P(water vapor).

Gas stoichiometry mass-volume relationships

Use ideal gas law or molar volume at STP.

Kinetic-Molecular Theory

Describes motion and behavior of gas particles (constant motion, elastic collisions).

Diffusion (definition)

Mixing of gases.

Effusion (definition)

Gas escaping through a small hole.

Real gas deviations

Nonideal behavior increases at high pressure and low temperature.

Why real gases deviate

Particles have volume and experience intermolecular forces (unlike ideal model).