Lab 1: Intermolecular Forces

Question 1

Purpose

Answer 1

Investigate relationship of dispersion forces and hydrogen bond forces

Question 2

When does evaporation occur in experiment?

Answer 2

When probe is removed from liquid’s container

Question 3

What kind of process is evaporation?
Result?

Answer 3

Endothermic process
Results in temperature decrease

Question 4

What is magnitude of temperature decrease related to?

Answer 4

Strength of IMF of attraction between molecules

Question 5

In this experiment, study what and related to what?

Answer 5

Temperature changes caused by the evaporation of several liquids
and relate temperature changes to strength of IMF of attraction

Question 6

Liquids with weaker intermolecular forces

Answer 6

Temperature change is greater because there is greater evaporation

Question 7

Two types of organic compounds in experiment

Answer 7

Alkanes and Alcohols

Question 8

Two alkanes

Answer 8

Pentane (C5H12) and Hexane (C6H14)

Question 9

Alcohols contain what

Answer 9

-OH functional group, + carbon and hydrogen atoms

Question 10

Two alcohols

Answer 10

Methanol (CH3OH) and Ethanol (C2H5OH)

Question 11

Examine molecular structure of alkanes and alcohols for what

Answer 11

Presence and relative strength of two IMF: hydrogen bonding and dispersion forces

Question 12

Dispersion forces and increase as

Answer 12

Exist between any two molecules
Generally increase as the molecular weight of the molecule increases

Question 13

Hydrogen bond

Answer 13

Can occur when a molecule has a hydrogen atom bonded directly to N, O, or F atom (the donor) and that hydrogen is attracted to a lone pair on an N, O, or F atom in another molecule (the acceptor)

Question 14

What must be present for a hydrogen bond to occur

Answer 14

Both a donor and acceptor