Chemistry 521

Definitions

100

Solvent and Solute

Solvent- a substance that has other substances dissolved in it. (Kool aid the water is the solvent)

Solute- a substance that is dissolved in a solution. (Saltwater the salt is the solute).

200

London Dispersion Force of Attraction and Dipole-Dipole Force of Attraction

LD-The temporary attraction force between the two momentarily polar molecules.

DD-The attraction between the negatively charged end of one polar molecule and the positively charged end of another polar molecule.

300

Ion-Dipole Force of Attraction

the force of attraction (electrostatic force of attraction) between an ion and a polar molecule.

400

Network Covalent Solids

Atoms covalently bond continuously in 3-D arrays. Happens with carbon and silicon.

500

Define Miscible and Immiscible

Miscible- liquids that readily dissolve in one another (ethanol and water)

Immiscible-liquids that do not readily dissolve in one another. (oil and water)

Forces

100

What are the Intermolecular Forces in Pure Substances?

London Dispersion, Dipole-Dipole, Hydrogen Bonding

200

Ionic Compound has what type of bonding?

Ionic bonds (+ ion and - ion)

300

A student mixes HF with PCl3 at 0oC and forms a liquid mixture.  What types of intermolecular forces are present between the two components of this liquid mixture, HF and PCl3?

Dipole-Dipole & London Dispersion

400

What do metallic bonds have?

A sea of free electrons.

(free to flow about the crystal of positive metal ions)

500

Rank the Intermolecular and Intramolecular forces from strongest to weakest

1. Network Covalent Compounds (SiO₂ and C_40..)

2. Ionic Compounds (oppositely charged ions)

3.Metallic (sea of free electrons)

4.Covalent Compounds (Hydrogen Bonding>Dipole-Dipole> London Dispersion)

Boiling Points

100

Cl_{2 (g)}  VS  IBr_(s)

IBr 

*Dipole-Dipole and London Dispersion*

(Cl₂ has only London Dispersion (non-polar))

200

What has a higher boiling point saltwater or pure water?

Saltwater

300

Explain the difference in boiling points between Cl₂ and C₄H₁₀

Cl₂ : LD, 34e^-

C₄H₁₀ : LD, 34e^-

C₄H₁₀ has a greater surface area so it will have stronger LD forces making it have the higher boiling point.

400

Using the information that you know about intermolecular and intramolecular forces, determine the ranking of boiling points for the following substances (lowest to highest). State the type of forces in each element/compound and use that information to determine the boiling points. HCl, CHF₃, CH₄, and HF.

HCl: LD, DD

CHF₃ : LD, DD

CH₄: LD

HF: LD, DD, HB

Lowest to highest: CH₄, HCl, CH₃F, HF

500

Using the information that you know about intermolecular and intramolecular forces, determine the ranking of boiling points for the following substances (lowest to highest). State the type of forces in each element/compound and use that information to determine the boiling points. Fe, HF, NaCl, HBr, SiO₂ 

Fe: Metallic Bond

HF: LD, DD, HB

NaCl: Ionic Bond

HBr: LD, DD

SiO₂ : Network Covalent

Lowest-Highest: HBr, HF, Fe, NaCl, SiO₂

Solutions

100

What original two states of a solute and solvent would give you the solution of mothballs in air?

solid (solute), gas (solvent)

200

How do you dissolve a compound at a molecular level?

1.Weaken/Break the FOA between the solute particles.

2.Weaken/Break the FOA between the solvent particles.

3.The attraction between the solute and the solvent particles replaces the original FOA

300

What is the worst electrical conductor, metals, ionic compounds, or covalent compounds?

Covalent compounds (no charges make them poor conductors)

400

What original two states of a solute and solvent would give you the solution of carbonated drinks?

gas(solute) and liquid (solvent)

500

Which compound is more brittle, ionic compounds or covalent compounds?

Ionic compounds

(held together by ionic bonds so when stressed the substance will break along the plane where the molecules are bonded.)