Name _________________________________________________________
Ionic Formulas Lab Answer Key
1. Write a balanced equation for the reaction between aqueous solutions of iron (III) nitrate and sodium hydroxide.
Fe(NO3)3(aq) + 3NaOH(aq)  3NaNO3(aq) + Fe(OH)3(s)
2. Write an overall ionic equation for the above reaction.
Fe3+ (aq) + 3NO3-(aq) + 3Na+(aq) + 3OH-(aq)  3Na+(aq) + 3 NO3-(aq) + Fe(OH)3(s)
3. Write a net ionic equation for the reaction.
Fe3+ (aq) + 3OH-(aq)
Test Tube
# of drops of
0.1 M
Fe(NO3)3
# of drops of
0.1 M NaOH
Ratio of Fe3+
to OHDraw each
tube, and
label the
color of the
solution
above the
precipitate.
Limiting
reagent
Excess
reagent
 Fe(OH)3(s)
#1
4
#2
6
#3
9
#4
12
#5
18
#6
24
32
30
27
24
18
12
1:5
1:3
1:2
1:1
2:1
NaOH
NaOH
NaOH
1:8
Fe(NO3)3
NaOH
Fe(NO3)3
NaOH
Fe(NO3)3
Fe(NO3)3
Fe(NO3)3
4. Which test tube actually had the most precipitate?
5. According to the formula for the precipitate, which tube theoretically should have the most precipitate?
6. If there is a difference between the theoretical and the actual, what is a possible reason for the difference?
7. Fe3+ ions in solution impart a rusty-color to the solution. Which tubes have Fe3+ ions in solution?
8. What could you do to show evidence that there are Fe3+ ions in solution in test tube #6, but not in test tube #1?
9. List all the ions in solution in test tube # 4.
10. How many total drops of NaOH would be needed to precipitate out all the Fe 3+ ions in test tube #5?
11. How many total drops of Fe(NO3) would be needed to precipitate out all the OH- ions in test tube #2?