Chapter 1-8 Review: Ions, Acids & Bases, Hydrogen Bonds, and Water Properties

Flashcards covering ion stability (octet), pH/pOH, acids and bases definitions (Arrhenius and Brønsted–Lowry), hydrogen bonding, water properties (high heat capacity and vaporization), hydration shells, and salt dissolution in water.

What is the goal of forming ions in terms of electron configuration?

To achieve a stable octet by obtaining the same electron configuration as a noble gas (eight valence electrons).

How can you infer the typical charges of ions from periodic groups without memorizing every ion?

Group 1 = +1, Group 2 = +2, Group 6 = −2, Group 7 = −1; use the group to predict common ion charges.

When an element on the left side of the periodic table forms ions, what process does it usually undergo?

It tends to lose electrons to reach a stable, noble-gas-like configuration.

What does pH measure?

The negative logarithm of the hydrogen ion concentration; lower pH indicates more H+ and greater acidity.

What does H+ represent in acid-base chemistry?

A proton; the hydrogen ion.

What does HCl dissociate into when placed in water?

H+ and Cl− ions.

What defines a strong acid versus a weak acid?

A strong acid fully dissociates in water; a weak acid only partially dissociates.

What is pOH?

The negative logarithm of the hydroxide ion concentration [OH−]; related to pH (pH + pOH ≈ 14 at 25°C).

What is a base in the Arrhenius sense?

A substance that produces OH− ions in water.

What is the Brønsted-Lowry definition of an acid?

A substance that donates a proton (H+).

What is the Brønsted-Lowry definition of a base?

A substance that accepts a proton (OH-).

What term describes a substance that can act as both an acid and a base depending on the situation?

Amphoteric (amphiprotic); water is a classic example.

What is hydrogen bonding?

A relatively strong intermolecular attraction where a hydrogen attached to an electronegative atom (O, N) associates with another electronegative atom.

Which atoms commonly participate in hydrogen bonding with hydrogen?

Oxygen and nitrogen (and fluorine in some cases); via O–H and N–H bonds.

Why does water have the property that ice floats on liquid water?

Ice is less dense than liquid water due to the open hydrogen-bonded lattice in ice.

What causes water to have a high boiling point and high heat capacity?

Extensive hydrogen bonding between water molecules, creating many weak intermolecular interactions that require energy to break.

What is meant by a calorie versus a Calorie in this context?

A calorie is the energy to raise 1 g of water by 1°C; a Calorie (capital C) = 1000 calories (kcal).

What is heat of vaporization?

The energy required to convert liquid water to water vapor; water has a relatively high heat of vaporization.

What is the hydration shell?

The surrounding layer of water molecules around dissolved ions, stabilizing them via ion-dipole interactions.

In water’s hydration around Na+ and Cl−, which part of water points to each ion?

Around Na+ the oxygen (negative end) points toward the ion; around Cl− the hydrogen atoms (positive ends) point toward the ion.

What primarily drives the dissolution of salts in water beyond simple ionic attraction?

Water–ion interactions (hydration shells) are strong enough to overcome ion–ion attractions, pulling apart the salt into solvated ions.

How does temperature affect the solubility of gases in water?

Gas solubility decreases as temperature increases.

What is the relationship between water and solubility/solvent properties in general?

Water is a polar solvent; it dissolves polar and ionic solutes well due to hydrogen bonding and dipole interactions.