•+Ch+13+Solutions

=Chapter 13 Properties of Solutions=

Use the following links to navigate through the chapter:
 * The Solution Process
 * Solubility and Saturated solutions
 * Factors Affecting Solubility, LeChatelier's Principal
 * Ways of Expressing Concentration Molarity, Molality, mole fraction, ppm
 * Colligative Properties (vapor pressure, boiling point elevation, freezing point depression, osmotic pressure)



Homework assignments for the entire chapter are at

My class notes for the entire chapter are at

A review of Chapter 13 colligative property equations including the van't Hoff factor is at [|Ch 13 Review.pdf] This is a good test review.

Here is an [|animation of NaCl dissolving in water] (scroll to the bottom of the page and click on Salt Dissolving in Water, sixth file from the top in the Chemical Animations section). If you watch carefully you can see three processes occur: sodium and chloride ions peel off the solid surface (endothermic - break ionic bonds), water molecules separate from each other to make a cavity for the ions (also endothermic - break london, dipole and hydrogen bonds), and hydration of the sodium and chloride ions by water (exothermic - formation of ion dipole bonds). ​

 =**An Aside on ATP/ADP**=

Breaking Bonds Requires Energy an endothermic process (even for ATP, there is nothing special about this molecule) Making Bonds Releases Energy -- an exothermic process (no exceptions)

So why does the conversion of ATP to ADP release energy????????? One of the phosphate groups break off and energy is released. Isn't this the opposte of what you just said?

The explanation, gentle reader, is that some other exothermic things are going on at the sime time as the endothermic bond breaking, very similar to Figure 1 above.

Although breaking the bond to release the phosphate group. the hydration of the resulting phosphate ion and ADP residue by water molecules is __exothermic and releases the energy used by the cells__. So it is the solvation and generation of intermolecular bonds, specifically new ion dipole bonds, that releases that energy. __Don't you believe anything else you hear!__ Check out these two website: this one is the [|correct explanation] (read the part on physical and chemical properties), and [|this one is a load of nonsense] (my apologies to the author).

= = = = = = = = =Concentration Calculations=




 * __Diluting Solutions__**

Let's say I wanted 5 M HCl and I could only find 12M in the storeroom. First I would estimate how much 5 M HCl I wanted, lets say 2 Liters. Then I use this equations M(initial) x volume(initial) = M(final) x volume (final) 12.0 x ? = 5.0 x 2 ? = (5 x 2 ) / 12 = 0.833 liters Therefore I need to take 833 mL of the 12 M stuff and addit slowly to about 1 liter of water. I probably should pack it in ice or just use ice water. Then, after it has cooled down, I carefully add enough water to bring the total volume to 2 Liters.


 * Dr. Rush's example of concentration conversions using hydrochloric acid as an example. **

A good link for [|practice calculating concentrations].

Do you want to learn how to [|convert between molarity and molality], mass percent and mole fraction?

=**Colligative Properties: The presence of a solute extends the temperature range over which the solvent is a liquid (HUH?)**= [|A Slide Show on Colligative Properties:]



A self test quiz on colligative properties is at the following link

An important worksheet which contains problems in which the vapor pressure of solutions containing two volatile liquids (HUH???? are you kidding???) are calculated is the Schaum worksheet at this link

What is Osmosis? Take a look at these pictures and you will see it how hard it is to get a big solvated molecule through a small hole in a membrane