Prelab #9—Week 1—Equilibrium
CHEM105 lab p. 1/2
Name _______________
Lab section: M T W Th F
Reading Assignment:
• Theory of experiment—see lab manual.
• Equilibrium and Le Chatelier’s Principle—Zumdahl, Chapter 6.
Questions:
1) In the space available, define the following terms in your own words:
a. Le Chatelier's Principle ___________________________________________
_____________________________________________________________
b. Beer's Law (see Vitamin Pill lab) _____________________________________
_____________________________________________________________
2) Review the procedure for Part I where two reactants will be added as outlined in the
data table below.
a. Fill in the shaded cells in the table below. The concentrations that you will fill in
refer to the concentration immediately after the reactants are mixed but before
any reaction occurs to bring the system to equilibrium. Using the stock solution
concentrations and the amounts of each reactant, calculate the initial
concentration of the reactants. Then calculate the molar ratio.
Solution
Stock solution:
0.2M Fe3+
in 0.5 HNO3
Stock solution:
0.002M SCN-
in 0.5 HNO3
Fe3+
Vol.
(mL)
Fe3+
Conc.*
(M)
SCN-
Vol.
(mL)
SCN-
Conc.*
(M)
Water
Vol.
(mL)
TOTAL
Vol.
(mL)
Molar
Ratio of
Fe3+ to
SCN-
1
1.00
5.00
44
50.00
* This is the concentration immediately after the reactants are mixed but before any reaction occurs to bring the system to
equilibrium
