Unit 3.1 Flashcards
Intermolecular forces - weaker
they spread apart
as boiling point increases
intermolecular force increases
because it will use the most energy to break apart
what is an ideal gas
a gas that its assumed theres no attraction between the molecules
what is a real gas
a gas when its cooled down theres more attraction between molecules
ideal gas law formula
PV=nRT
dipole
when a molecule has two opposite charges
electrons shared unevenly
dipole-dipole
the positive end of one polar molecule and the negative end of one polar molecule.
PERMANENT versions of london dispersion forces.
+1 <3 -1w
London dispersion forces
temporary fluctuating dipoles (hallways)
The larger the surface area of a molecule is…
the stronger the london dispersion forces are
bc then they have a better chance at reaching other molecules and interacting with them
polarizability
how easily the electron cloud of a molecule can be distorted (like when an electron are loosely held the molecule is more polarizable)
polarizability increases as
increasing number of electrons and the size of the electron cloud
dipole-induced dipole
polar-nonpolar
dipole-dipole
polar-polar
ion-dipole
ion-polar
WHAT ARE WE GETTING ON THIS TEST
10000000000000000000
LDF strength
weakest
Dipole-dipole strength
medium
Hydrogen bond strength
strongest
more electrons=
greater strength of LDF
greater LDF & more electrons=
higher boiling point
and more polorizable
if theres two of the same molecule (C5H12) but they are stuctured so one has more surface area than the other, why does the one thats bigger have a higher boiling point?
bc it has greater attraction bc
greater surface area=more contact between molecules
so greater attraction=more strength to break them apart to boil
when theres two different molecules but they have the same size electron cloud, is the polar one or nonpolar one gonna have greater attraction
attraction between polar ones are greater bc nonpolar is just LDF and polar would be LDF and dipole-dipole which is stronger
which one has a higher boiling point:
nonpolar molecule
or polar molecule
polar
bc it has LDF and dipole-dipole so its stronger than just the nonpolar with just LDF
If theres a mixture of CCl4(g) and HCl(g) but then it goes from 600k to 340k temp
but CCl4 has condensed and changed from a gas to a liquid while HCl stays the same, which one has a higher boiling point?
CCl4 has the higher boiling point bc it already started to condense so it’s intermolecular forces are increased now and it’s stronger
S-O-S
S-C-O
identify their intermolecular forces
nonpolar, LDF
polar, LDF, dipole-dipole
What trumps the intermolecular force strength rules?
the amount of electrons matter more than if its dipole-dipole or hydrogen or LDF
Br2 is nonpolar with larger electron cloud
BrCl is polar with a smaller electron cloud
Br2- 332K boiling point
BrCl- 278K boiling point
which one is stronger
Br2 is stronger, even though it is nonpolar, it has a larger electron cloud (more electrons) and its boiling point is larger so more attractive forces (polarizability)
what type of intermolecular force is responsible for the difference in boiling points in two molecules
LDFs
Larger LDF=
more attraction, higher boiling point
why cant nonpolar molecules bond with water
because they dont have the space to make partial charges, so it cant make the hydrogen bonds with water
“has more electrons so it has stronger attraction”
polarizability
Why is H-S-H weaker than H-O-H
periodic table:
O
S
bc O has greater electronegativity than S
Br2= 332K
2BrCl=278K
why does Br2 have a higher boiling point that 2BrCl
bc Br2 has more electrons, therefore greater polarizability
