Khrystyna’s CHE 132 Archived Resources

Tips

Below is a list of things you should review after Week2:

  • You should be able to define energy, work and heat.
  • Energy = w + q, where w is work, and q is heat
  • q = mC ΔT, w = -P
  • Remember the two types of calorimetry: bomb and coffee cup
  • In bomb calorimetry- volume is constant, and it measures  ΔE of the reaction
  • In a coffee cup calorimetry- pressure in constant, and it measures  ΔH of the reaction
  • ΔH = ΔE + P Δ V
  • Also, remember that q system = -q surroundings

 

Heating curve of a substance

*Notice the equations that used in each segment, and how to solve for q.

Remember Graham’s Law:

Remember, that if you are given time it is not the rate. The rate in the number of molecules that are effusing per given time; rate = #/time.

Practice determining inter molecular forces, relative boiling points, etc!

Boiling-point elevation describes the phenomenon that the boiling point of a solvent will be higher when another compound is added, meaning that a solution will have higher boiling point than a pure solvent.

Freezing-point depression describes the process in which adding a solute to a solvent decreases the freezing point of the solvent, meaning that a solution will have a lower boiling point.

Here are some explanations and worked problems and videos regarding the material.

 

 

Few rules that are useful, when trying find Keq for manipulated chemical reaction.

Let’s review:

The equilibrium constant of a chemical reaction is the value of the reaction quotient when the reaction has reached equilibrium.

Below is our common reaction

aA+bBcC+dD, for which 

 (forward)

Below are the rules for Keq manipulation, your textbook (p 615) has explanations to these rules.

1. If the chemical reaction is reversed, to find new Keq (reversed), we need to invert Keq (forward).  1/Keq forward

2. If the chemical reaction is multiplied by a coefficient (n), we need to raise our Keq to the power n. Keq^n

3. If we add two or more chemical reactions together to obtain an overall reaction, we need to multiply  Keq(s). Keq (reaction 1) * Keq( reaction 2)= Keq overall.

 

Videos and Handouts

Derivation for a second order reaction

Mechanism and rate determining step

Catalysis

Relating Kc and Kc

Le Chatelier’s Principle Worksheet