experiment 3-4 concepts

Question 1

molecules in solid and liquid states are held together by ______________ forces

Answer 1

intermolecular forces

Question 2

2 general types of intermolecular forces

Answer 2

1. London Dispersion Forces
2. Dipole-dipole Forces

Question 3

Forces found in NON-POLAR MOLECULES and POLAR MOLECULES

Answer 3

NPM - LDF

PM - DDF and LDF

Question 4

Special type of DDF

Answer 4

Hydrogen Bonding

Question 5

In hydrogen boding, what is attached to H

Answer 5

O, N, F

Question 6

what is the energy needed to increase the surface area of a liquid by one unit

Answer 6

Surface Tension

Question 7

Unbalanced/Balanced IMFA in the surface of liquids cause surface tensions

Answer 7

Unbalanced

Question 8

Unbalanced/Balanced IMFA causes surface tension

Answer 8

Unbalanced

Question 9

Effect of IMFA on Melting and Freezing Point

Answer 9

Stronger = Higher

Question 10

What type of net force do IMFA create on surface of liquids

Answer 10

Inward Net Force

Question 11

Effect of IMFA on Melting/Freezing Point

Answer 11

Stronger IMFA = High MP and FP

Question 12

What states exist in equilibrium at Melting and Freezing Point temperatures

Answer 12

solid and liquid

Question 13

What must be supplied to solids to turn into liquid and why

Answer 13

ENERGY - break IMFA

Question 14

What will be used to determine the ff:

1. Melting Point
2. Freezing Point

Answer 14

1. Melting Point Determination Apparatus
2. Cooling Curve

Question 15

Relationship of KE and Temperature in Freezing

Answer 15

Direct Relationship

Question 16

What is PE in Freezing

Answer 16

Stored Energy in Chemical Bonds

Question 17

What are COLLIGATIVE PROPERTIES

Answer 17

DEPENDS on molarity of solute present (not on nature)

Question 18

Freezing Point Lowering Formula

Answer 18

T solvent - T solution = kf m

where:
Tfo = freezing point of the pure solvent
Tf = freezing point of solution
kf = freezing point depression constant of the solvent
m = molality of the solution

Question 19

Molality formula

Answer 19

m = T solvent - T solution / kf

Question 20

Molar Mass Solute formula

Answer 20

MM = [(mass solute)(kf) / (T solvent - T solution)(kg solvent)]

Question 21

Molarity VS Molality

Answer 21

Molarity = moles solute / Liter solution

Molality = moles solute / kg solvent

Question 22

“Arrest” VS “Break” Temperature

Answer 22

A: plateau during phase change

B: downward slope after phase change

Question 23

Downward slope and Plateau Description (KE and PE)

Answer 23

DS: KE decreases, PE constant
CS: PE decreases, KE constant

Question 24

Sensible vs Latent Heat

Answer 24

S: energy required to change the temperature of the substance with no phase change.

L: energy absorbed or released by a substance during phase change

Question 25

3 cooling curve variations

Answer 25

1. no distinct plateu
2. no distinct plateu

get average of first and last point right before downward slopw

Question 26

Reason for Cooling Curve 1 and 2

Answer 26

Impurities interrupt the organized crystal packing during solidification

Question 27

Two general types of IMFA

and what do you collectively call these 2

Answer 27

London Dispersion Forces
dipole-dipole forces

van der Waals forces

Question 28

compounds ending with -one contains what type of bonding

Answer 28

no hydrogen bonding