Reagent and Mole Ratio

Determining the Stoichiometry of Chemical Reactions
Objective
In this lab we took Fe(NO3)3 and NaOH and mixed 7 different mole ratios in graduated cylinders to determine what the mole ratio is. We also did the same thing with solutions of CuCl2 and Na3PO4. We determine the mole ratios by graphing the volume of reactant #1 vs. volume of precipitate for each reaction.
Data
Part 1.)
Cylinder
1
2
3
4
5
6
7
Fe(NO3)3, 0.1 M, ml
5
10
12
15
17
20
24
NaOH, 0.1 M, ml
55
50
48
45
43
40
36
Fe:OH mole ratio
1:11
1:5
1:4
1:3
2:5
1:2
2:3
Volume Precipitate (ml)
6
10
12
16
22
8
11

Appearance
Reactant Fe(NO3)3
Tinted orange/brown
Reactant NaOH clear Product Parcipitate
Fuzzy dark brown

Part 2.)
Cylinder
1
2
3
4
5
6
7
CuCl2, 0.05 M, ml
10
20
24
30
36
40
50
Na3PO4, 0.05 M, ml
50
40
36
30
24
20
10
Cu:PO4 Mole Ratio
1:5
1:2
2:3
1:1
3:2
2:1
5:1
Volume Precipitate (ml)
11
23
27
35
44
39
19

Appearance
Reactant CuCl2 tinted blue
Reactant NaOH clear Product Parcipitate cloudy blue

Questions
1.) On graph paper, plot the milliliters of reactant #1 versus volume of precipitate for each reaction. For the copper chloride graph, draw the two best-fit straight lines through the data points and determine their point of intersection.

Cu:PO4 stoichiometric ratio = 3:2
Balanced Equation = 3CuCl2 + 2Na3PO4 Cu3(PO4)2 + 6NaCl

2.) For the iron nitrate graph, draw the best-fit line through the ascending data, and a smooth curve through the descending data. Determine their intersection point. From the point of intersection, determine the stoichiometric mole ratio for each reaction. Write out the correct balanced equation for each reaction.

Fe:OH stoichiometric ratio = 2:5
Balanced equation = 2Fe(NO3)3 + 3OH Fe2O3 + 3H(NO3)

3.) Explain how this method allows you to find the mole ratio of reactants.

This method allows you to find the mole ratio of the