Chapter 16.3 Test Flashcards
What is another name for external bonds?
Intermolecular forces
What is the scientific name for external bonds?
Van der Waals forces
What are Van der Waals forces
- weakest of all bond types
- bonds between molecules
What do Van der Waals forces determine?
Properties of molecular compounds such as boiling point or freezing point.
What are the three types of Van der Waals forces?
- Dipole-Dipole Interaction
- Hydrogen Bond
- London Dispersion Forces
What is a Dipole-Dipole Interaction?
Attraction between 2 polar molecules.
Why do dipole-dipole forces occur?
Because of the opposite or partial charges on their neighboring molecules
Describe what a dipole interaction looks like.
Two polar molecules that have opposite partial charges attracting to each other.
What makes polar interactions stronger or weaker?
The difference in electronegativity between the positive end of one molecule and the negative end of the other molecules.
What is a hydrogen bond?
A type of dipole-dipole interaction, but it involves Hydrogen bonding to a very electronegative atom. It is the strongest of all the Van der Waals forces.
What elements are usually involved in hydrogen bonds?
N, O, F, Cl bonded to Hydrogen
Why is water wet?
Because molecules attach and bond and the bonds are strong enough to hold them together in liquid form.
What is the main factor to look for in hydrogen bonds?
One exposed proton with nothing covering it. The positive charge will attract anything negative so it will pull a negative electron from another atom.
What are London Dispersion Forces?
Attraction between molecules caused by random shifting of electrons within molecules.
What are characteristics of London Dispersion forces?
- they are the weakest Van der Waals force
- they exist between all molecules
What is electrons relation to molecular forces?
The more electrons in a molecule, the stronger the force of attraction.
What is the relation between molecules and states of matter?
If molecules do not attract, they are gases, they need stronger bonds and attract together to be liquids and if they attract even stronger, they become solids.
Are gases polar or non polar? Why?
non polar because they have no charge
How do you turn gases into liquids or solids?
- change the conditions to very cold which slows down molecular motion and electron motions
- compress the gas to bring the molecules closer together
What is an induced dipole?
When atom’s poles are created by random shifting of electrons and instantaneous charges are created.
Why does it not rain nitrogen?
Instantaneous charges are caused by random shifting of electrons.
What are the relationships between polar and non polar molecules with respect to solubility?
Polar dissolves polar, and vice versa
What is a dipole moment?
The product of the separation of the ends of a dipole and the magnitude of the charges. It compares the charges of each molecule being bonded.
Why does soda go flat in warm temperature?
Water is polar and CO2 is non polar and they will not dissolve over time.
