Gases

Question 1

Properties of Gases

Answer 1

• Highly compressible (Boyle’s law) P1V1=P2V2
• Thermally expandable (Charle’s Law)
  V1/T1=V2/T2
• Low viscosity and density
• Infinitely miscible
• Vole of gas is proportional to moles
  V1/n1=V2/n2

Question 2

Ideal Gas Law

Answer 2

Combination of Simple Gas Laws

Provided on Data sheet
V = nRT / p
pV = nRT

Question 3

Viscosity

Answer 3

Resistance to flow

Question 4

Molar Volume

Answer 4

The volume of an ideal gas under 273.15 K and 1 atm pressure aka STP

22.4 L at STP is one mole of gas

Question 5

Why does ideal gas law or kinetic molecular theory fell?

Answer 5

Real gases have volume
Interparticle forces (attraction and repulsion between particles)
Low temperature or high pressure

Question 6

States and IPF

Answer 6

Gas: no IPF
Liquid: random IPF
Solid; IPF Pattern

Question 7

Sublimation

Answer 7

Solid to gas

Question 8

Fusion

Answer 8

Solid to liquid

Question 9

Deposition

Answer 9

Gas to solid

Question 10

Phase Change and Energy

Answer 10

S-l-g means energy absorption (endothermic)

g-l-s means energy released (exothermic)

Question 11

Change in H trends w/ IPF and Phase Changes

Answer 11

DeltaH for vaporization is stronger than DeltaH for fusion because vaporization has to break all IPF while fusion only has to break some.

Question 12

Triple Point

Answer 12

On phase diagrams when all 3 phases coexist

Question 13

Liquid-Gas Equilibria

Answer 13

When the rate of vaporization matches the rate of condensation at a dynamic equilibrium as long as pressure is constant

Question 14

Vapor Pressure

Answer 14

A constant pressure of gas in a closed container in Liquid-Gas Equilibrium that depends only on the type of liquid and temperature, not the amount of liquid.

NEEDS a liquid

Question 15

Vapor Pressure IPF trend

Answer 15

Higher IPF means lower VP because molecule wants to stay a liquid

Question 16

Temperature and Vapor Pressure trend

Answer 16

Greater the temperature, greater the VP

Question 17

Normal Boiling Point

Answer 17

The temperature at which the vapor pressure is 1 ATM

Question 18

Solid-Liquid Equilibria

Answer 18

Equilibrium between solids and liquids. 0 degrees celsius

Aka melting point

Not affected by pressure

Question 19

Solid-Gas Equilibrium

Answer 19

Point of sublimation when IPF are too week to keep particles together.

Question 20

Supercritical Fluids

Answer 20

The boundary where phases will disappear between gasses and liquids when a closed container of liquid is heated and the density of liquids when a decreases and density of gas will decrease until both densities are EQUAL

Question 21

Ion-Dipole IPF

Answer 21

between ions and polar molecules because of partial negative charges

Question 22

Dipole-Dipole IPF

Answer 22

Occurs between polar dipoles aligned to maximize attractions

Question 23

Hydrogen Bonding IPF

Answer 23

Special kind of dipole-dipole force that may occur between molecules and H atom in some, highly electronegative atom (N, O, F) and needs a lone pair

Question 24

Induced Dipoles

Answer 24

Attractions between nonpolar molecules where an induced dipole could form from momentarily shifts in electron density

Aka instantaneous dipole

Question 25

Ion-induced Dipole Forces

Answer 25

Between ions and nonpolar molecules. Ex) Fe 2+ in hemoglobin

Question 26

Dipole-induced dipole forces

Answer 26

Between polar and nonpolar molecules Ex) O2 gas and water

Question 27

Instantaneous dipole-induced dipole

Answer 27

Between nonpolar molecules or single atoms

Question 28

Polarizability

Answer 28

The ease with which the electron cloud can be distorted to create a charge separation Increases with greater number of electrons and a larger molecule size

Question 29

Polarizability Atom Trends

Answer 29

Increases down a group because the elements become bigger Decreases across a period as the electrons are held more tightly

Question 30

Polarizability Ion Trends

Answer 30

Anions are more polarizable than cations