Bonding, Structure, and Gases

Flashcards about lattice structures, bonding, structure, gas laws and kinetic theory of gases

What type of compounds are crystalline lattices most commonly found in?

Ionic, metallic, and covalent compounds.

What force holds ionic compounds together in giant ionic lattices?

Electrostatic force between positively charged metal (cation) ions and negatively charged non-metal (anion) ions.

What determines the type of lattice formed by ionic compounds?

The sizes of the positive and negative ions arranged in an alternating fashion.

Give two examples of ionic compounds with cubic lattices.

MgO and NaCl.

In a general ionic lattice, how are ions packed?

Based on their relative size.

What type of bond holds covalent compounds together?

Bonds between non-metals in which electrons are shared between the atoms.

Name three substances that form simple molecular lattices.

Iodine, buckminsterfullerene (C60), and ice.

Name three substances that form giant molecular lattices.

Silicon(IV) oxide, graphite, and diamond.

Why do giant molecular lattices have higher melting and boiling points?

They require more energy to overcome the intramolecular and/or intermolecular forces.

What surrounds the metal ions in metallic lattices?

A 'sea' of delocalised electrons.

Describe the arrangement of metal ions in metallic lattices.

Often packed in hexagonal layers or in a cubic arrangement.

What are graphite, diamond, and buckminsterfullerene?

Allotropes of carbon, different structural forms of the same element (carbon).

Which physical properties of substances are affected by bonding and structure?

Melting and boiling points, electrical conductivity, and solubility.

Why are ionic compounds strong?

Due to the strong electrostatic forces that keep the ions strongly together.

Why are ionic compounds brittle?

Because ionic crystals can split apart when subjected to force.

How does charge density affect the melting and boiling points of ionic compounds?

Melting and boiling points increase with charge density due to the greater electrostatic attraction of charges.

In what state do ionic compounds conduct electricity?

When molten or in solution.

Why are metallic compounds malleable?

When force is applied, the metal layers can slide, and the metallic bonds are re-formed.

What two factors increase the melting/boiling point of metallic compounds?

The greater the number of delocalised electrons and the smaller the cation.

Why do simple covalent lattices have low melting and boiling points?

These compounds have weak intermolecular forces between the molecules.

Why don't simple covalent lattices conduct electricity?

There are no charged particles.

Why are giant covalent lattices hard or soft?

Graphite is soft due to weak forces between carbon layers; diamond and silicon (IV) oxide are hard due to a 3D network of strong covalent bonds.

Why does Graphite conduct electricity?

Graphite has delocalised electrons between the carbon layers which can move along the layers when a voltage is applied

hat causes gas pressure?

Gas molecules constantly colliding with the wall of the container.

Describe the relationship between volume and pressure of a gas at constant temperature.

Volume is inversely proportional to pressure.

Describe the relationship between temperature and pressure of a gas at constant volume.

Temperature is directly proportional to pressure.

State the five assumptions of the kinetic theory of gases:

1. The gas molecules are moving very fast and randomly.

2. 2. The molecules hardly have any volume.

3. 3. The gas molecules do not attract or repel each other (no intermolecular forces).

4. 4. No kinetic energy is lost when the gas molecules collide with each other (elastic collisions).

5. 5. The temperature of the gas is related to the average kinetic energy of the molecules.

Under what conditions do real gases deviate from ideal gas behaviour?

At very high pressures and low temperatures.

Why do intermolecular forces cause real gases to deviate from ideal behavior?

Attractive forces between molecules pull them slightly inward, so they hit the container walls with less force than expected, making the measured pressure lower than predicted.