Unit 9 – Solution Chemistry
Chem 11
Sec 9.4
Polar and Nonpolar Solvents
Copy the table, pg 205 #17
Look at the common solvents on pg 204 and label them as either polar or nonpolar
Solvent
Polar or
nonpolar
Water
Methanol
Ethanol
Benzene
Solvent
Polar or
nonpolar
Ethoxyethane
Acetone
Acetic acid
Chloroform
Solvent
Polar or
nonpolar
Carbon tetrachloride
Heptane
Liquid ammonia
After completing many experiments concerned with MIXING polar and nonpolar solvents with polar
and nonpolar solutes points to the following conclusion
Polar or Ionic solutes dissolves in polar solvents
Nonpolar solutes dissolves in nonpolar solvents
LIKE DISSOLVES LIKE
Here is the “short” reason why…
Polar and ionic solutes have strong bonds holding the solid together. Nonpolar solvents have
weak London forces and can not exert enough energy to over come the strong bonds. Only polar
solvents have sufficient attraction to the solute to be able to “pull” the solute out of the crystal
and into the solution.
Therefore polar solvents can dissolve polar solutes
Nonpolar species do not possess positive and negative ends. Therefore there is no attraction to polar or
ionic species. Only nonpolar solvents can attract nonpolar solutes, because they both have weak
London forces.
Therefore nonpolar solvents can dissolve nonpolar solutes
http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/thermochem/solutionS
alt.html
Unit 9 – Solution Chemistry
Chem 11
Sec 9.4
Polar and Nonpolar Solvents
Look at the common solvents on pg. 204 and label them as either polar or nonpolar
Solvent
Polar or
nonpolar
Solvent
Polar or
nonpolar
Solvent
Water
Ethoxyethane
Carbon tetrachloride
Methanol
Ethanol
Benzene
Acetone
Acetic acid
Chloroform
Heptane
Liquid ammonia
Polar or
nonpolar
After completing many experiments concerned with MIXING polar and nonpolar solvents with polar
and nonpolar solutes points to the following conclusion
________ or ________ solutes dissolves in ________________
____________ solutes dissolves in ________________________
Here is the “short” reason why…
________ and ________solutes have ________ bonds holding the solid together. ____________
solvents have _______________________and cannot exert enough energy to over come the strong
bonds. Only ________ solvents have ____________ attraction to the solute to be able to “pull” the
solute out of the crystal and into the solution.
Therefore ________________can dissolve ________________.
Nonpolar species ____ ____ possess ________and ________ ends. Therefore there is ____
__________to polar or ionic species. Only ________ solvents can attract ________ solutes, because
they ________have _______ ____________ _____________.
Therefore ________________can dissolve ________________.
Unit 9 – Solution Chemistry
Chem 11
Sec 9.4 How to distinguish the MOST IMPORTANT BONDS or FORCES
in a substance
1. IONIC bond – is there a metal and a non-metal
2. COVALENT bond – 2 non metals
3. HYDROGEN bonds – look for an H bonded to an O, F or N
4. DIPOLE – DIPOLE force – asymmetric molecule; there will be a
electronegativity difference
5. LONDON force – present in all substances
Read page 204-206
HW pg 207 # 18-22, 23-27