CHEM 102 Lecture 12: CH 12 Chem

34 views3 pages
4 Feb 2017
Department
Course
Professor

For unlimited access to Class Notes, a Class+ subscription is required.

CH 12 Chem
Intermolecular Forces
- Moderate or strong force = liquid or solid w/ high melting and boiling points
- Weak force = gas w/ weak melting and boiling points
- Result of smaller charges interacting at greater distances
Dispersion Force (molecular)
- In all elements and compounds
- Arise from fluctuations in electron distribution where one side is negative and the other is
positive (instantaneous dipole)
- Weakest intermolecular forces
- Magnitude of the force depends on how easily the electrons polarize/move due to
instantaneuous dipole (positive end attracts the negative end of neighboring atoms),
which depends on the size of the electron cloud
- Greater electron cloud = greater dispersion force since electrons are held less
tightly and can move easier
- IMF force Increases w/ molar mass (and increases w/ boiling point)
EX: Which Halogen has the Highest Boiling Point?
Cl2, Br2, I2
I2 since it has the highest molar mass
Dipole Dipole (intermolecular)
- In polar molecules w/ electron rich and electron deficient regions
- Stronger than dispersion forces
- Permanent dipole → positive end of a polar molecule attracts the negative end of
another polar molecule
- Higher melting and boiling point
- miscible (can separate w/o separating into 2 states)
Hydrogen Bonds
- Polar molecules w/ H atoms bonded to F, O, or N
- strong boiling point
Ion Dipole Force
- Ions mix w/ polar compounds
- Positive end of polar molecule is attracted to negative ion
- Negative end of polar molecule is attracted to the positive ion
- Strongest
Vaporization and Vapor Pressure
- Vaporization:
- endothermic
- The process in which thermal energy overcomes intermolecular forces and make
a state change from Liquid → Gas
find more resources at oneclass.com
find more resources at oneclass.com
Unlock document

This preview shows page 1 of the document.
Unlock all 3 pages and 3 million more documents.

Already have an account? Log in

Get access

Grade+
$10 USD/m
Billed $120 USD annually
Homework Help
Class Notes
Textbook Notes
40 Verified Answers
Study Guides
1 Booster Class
Class+
$8 USD/m
Billed $96 USD annually
Homework Help
Class Notes
Textbook Notes
30 Verified Answers
Study Guides
1 Booster Class