AP CHEM Unit 3 properties of substances and mixtures

London Disperson Forces

• present in all molecules, but only a force in non-polar molecules

• strength increases as molecular size increases

• ex) Co2, CH4,

Dipole-Dipole Forces

• Occurs mainly in polar molecules with permanent dipoles

Hydrogen bonding

• Very strong; happens when H is bonded to N,O, or F

• ex) H20, H202, alcohols

Ionic & metallic bonds

Ionic (NaCal) and metallic (Fe) substances form lattices with extremely high melting points compared to molecular compounds

What impacts the boiling point?

IMF type, molar mass, polarity

Which has a stronger force?

Hydrogen bonding, dipole-dipole, or dispersion?

What is a triple point on a phase graph?

Where All 3 phases coexist.

critical point

Beyond this, liquid and gas merge into a fluid that is unrecoginizable

Where are metals on the periodic table?

Left side

Where are non-metals on the periodic table?

Right side

Metal + Nonmetal

ionic

Nonmetal + Nonmetal

Covalent

Non-polar and polar bonds cancel out when…

their shape is symmetrical

Non polar and polar bonds dont cancel out when…

their shape is asymmetrical

Boyles Law

P1V1=P2V2

Charles Law

P1V1=P2V2

Avogardros Law

V1/N1=V2/N2

metals conduct well in 

solid state due too delocalized electrons 

ionics conduct well in 

aqueous or molten states 

Critical point is when

The liquid and vapor phases become indistinguishable

Triple point is when

All three phases coexist at this unique T-P condition

When the triple point requires higher pressure, its triple point is above 1 atm

true

Non polar molecules with more electrons usually have a higher or lower boiling point than those with fewer electrons?

higher

Non polar molecules have only ____ as forces

London dispersion 

What is the order of increasing strength between bonds?

London dispersion < Dipole-dipole < Hydrogen bonding

electronic transition occurs when

an electron jumps from a lower energy molecular orbital to a higher one

infrared radiation causes 

molecules to vibrate and rotate at higher energy levels

The absorption of infrared radiation leads to

o an increase in molecular vibrational level