1. Due: Reaction rate WS Today: HW Pick up an iPad & Calculator
Factors the affect rates of reactions (quick review)
Concentration calculations HW
Concentration WS

2. In which diagram will the reaction go
Which diagram represents an endothermic reaction? Exothermic?
In which diagram will the reaction go
faster? Explain using evidence from the diagram 2

3. Factors Affecting Rate
Nature of Reactants
Ionic vs. Covalent
Temperature
Surface Area
Concentration/Pressure
Presence of Catalysts/Inhibitors 3

4. Endothermic Reaction w/Catalyst4

5. Exothermic Reaction w/Catalyst5

6. Calculations of Solution Concentration

7. Calculations of Solution Concentration: Molarity
Molarity is the ratio of moles of solute to liters of solution
3 M = 3 moles or [3] L

8. Calculations of Solution Concentration: Mass Percent
Mass percent is the ratio of mass units of solute to mass units of solution, expressed as a percent

9. Practice Problem
Seawater contains roughly 28.0g per liter. What is the molarity of sodium chloride in seawater?
How many grams of HCl are in a 2M solution?

10. Making Dilutions Only weaker solutions can be made.
MconcVconc = MdilVdil
  mol x L = mol x L
L L
The moles of conc. = the moles diluted

11. Sample problems:
 Describe how you would make 3 L of a 0.25 M calcium chloride solution.
Step 1. First figure out how many moles you will need.
Step 2 Convert the moles to grams.

12. Step 3 Describe the process. Include the use of a volumetric flask.

13. Sample problem:
 How would you make 4.00 L of a .15 M CaCl2 starting from a 2.5 M solution.
Mconc x Vconc = Mdil x Vdil

14. Sample Problem:
How would you make 2.0 L of M HCl, if you have a stock solution of 6.0 M HCl?

15. Calculations of Solution Concentration: Parts per Million
Parts per million is the ratio of mass units of solute to mass units of solution, multiplied by one million (106)

16. A Simplifying Assumption
1 ml of water = 1 gram of water
1000 ml of water = 1 liter = 1000 grams
Assume that solutions with water as the solvent have the density of pure water (1 mL = 1 gram)
It’s not true, but it’s close enough 