10 - Chemistry unit 2.1-2.4

Properties of solids (5)

* minimal deformability
* holds shape
* doesn't flow
* particles are closely packed in fixed positions - fixed shape and volume
* rigid - cannot be squashed, denser than liquids

Properties of plasma (6)

* no fixed shape or volume
* electrically conductive
* compressible
* low density
* expands to fill space
* will alway diffuse to surroundings

Properties of gas (6)

* particles have large spaces in between - no fixed shape or volume
* not rigid
* compressible
* low density
* expands to fill space
* will alway diffuse to surroundings

What are the 4 states of matter?

solid, liquid, gas and plasma

Properties of liquids (4)

* takes shape of container
* flow speed depends on viscosity
* slightly compressible or expandable
* sometimes diffusible

What 3 things contribute to what state a substance is in?

Chemical makeup, temperature and pressure

5 rules of significant figures

1. non-zero numbers are always significant
2. Zeros between non-zero numbers are always significant
3. All final zeros to the right os the decimal place are. significant
4. Zeros that act as placeholder are not significant. Convert quantities to scientific notation to remove the placeholder zeros.
5. Counting numbers and defined constants (the mole) have an infinite number of significant figures.

What is a polar covalent bond?

When electrons are shared unequally

What is electronegativity?

It is an atoms ability to attract a pair of electrons

Dipole-dipole characteristics (4)

* opposite poles
* can occur in both covalent bond and ionic bond
* in molecules with dipole, electrons are pulled closer towards one atom than another
* Based on electrostatic charges the particle positive attracts to the partial negative parts

Intramolecular

attraction within the same molecule

What 5 assumptions are made about the size, motion and energy of the particles?

1. All matter is made up of very small particles (atoms, molecules, ions, etc.)
2. All particles in a pure substance are the same; different substances are made of different types of particles
3. There is space between all particles
4. Particles are always moving randomly, and if they gain energy, they over faster
5. Particles are attracted to one another and the nature and strength of the forces of attraction depend on the type of particle

(London) dispersion forces characteristics (4)

* All compounds can experience this
* Weak forces resulting from temporary electron density shifts. Occurs will all types of particles
* Due to the constant kinetic movement of particles, temporary dipoles can occur for a split second
* electron density can “clump” onto one side

Hydrogen bonds characteristics (3)

* a special type of dipole-dipole forces
* occur between molecules that contain H-O, H-F, or H-N bonds (“F-O-N”)
* bond is stronger than a “normal” dipole-dipole bond

What is Kinetic Molecular Theory?

It is the theory of “moving molecules”

Intramolecular bonds (2)

Ionic and covalent

Intermolecular bonds (3)

Dipole-dipole, hydrogen and dispersion forces (LDF)

Intermolecular

attraction between molecules

solid to gas

sublimation

Exothermic phases

* Condensation
* Deposition
* Freezing

liquid to gas

vaporization

Endothermic phases

* Melting
* Vaporization
* Sublimation

gas to solid

deposition

Endothermic

absorbs energy

liquid to solid

freezing

Exothermic

release energy

gas to liquid

condensation

solid to liquid

melting

Dynamic Equilibrium

If the water is in a closed container, the system will find a balance, and the number of molecules captured backed into the liquid

vapor pressure

the pressure exerted on a liquid by it's vapor

Normal Boiling Point

the temperature at which the vapor pressure of a substance equals atmospheric pressure

Atmospheric pressure

the weight of the atmosphere above

The more particles that are in the vapor phase…

the greater the vapor pressure

What is the range of kinetic energy for a liquid held at a constant temperature?

the liquid at the bottom has lower kinetic energy then more at the top

Evaporation

liquid particles escaping into the gas phase

Volatility

the ease with which a substance vaporizes

Which bond is most volatile?

London Dispersion Force

What must happen for internal vaporization to occur?

the vapor pressure must be big enough that particles can overcome the atmospheric pressure and lift up the water above and form a bubble

Which bond is least volatile?

hydrogen bonds