Chase Bitterling
February 26, 2014
Chemistry
Double Replacement Reactions
Abstract: In this lab the purpose was to observe different ionic solutions being mixed with
other combinations and observe whiter a precipitate and note that a double replacement
reaction was taking place. A double replacement reaction is when two different compounds
react with each other. When this happens a cation and an anion break and form new bonds
with other counterparts. This was accomplished and the results that were taken were accurate
and precise. As expected there were some errors because the precipitate formed in some of
the mixtures were hard to see but eventually they were found and noted.
Introduction: In this lab we will be doing double replacement reaction and example of such a
reaction would be like the reaction of a antacid tablet that contains calcium carbonate that
would them mix with the hydrochloric acid that is found in your stomach. To sum it up a double
replacement reaction takes place between two ionic compounds that are dissolved in water
where the cation in one compound replaces the cation in the other compound to create two
new compounds. This new compound could be a precipitate, a gas, or water.
In this lab we will be mixing many pairs of aqueous solutions and ionic compounds
together. From there we will observe what happens when each is mixed and see which form a
precipitate. Then from there we will write balanced equations for each of the reactions.
Purpose: Is to find which combinations of ionic solutions form precipitates that indicate a
double replacement reaction has taken place by mix different chemicals safely and seeing
which ones from precipitates.
Procedure: After a well plate is obtained label the wells accordingly then using a micropipet
place 5 drops of silver nitrate into wells A1-4. In wells B1—4 place 5 drops of iron nitrate
solution and in wells C1-4 place 5 drops of copper (II) nitrate solution. Then add 5 drops of
sodium phosphate solution into wells A B and C 1 then record what you saw. In wells A B and C
2 add 5 drops of sodium sulfate solutions then record those observations. Then in wells A B and
C 3 place 5 drops of sodium hydroxide solution and again record observations. In the wells A B C
C3 and C 4 place 5 drops sodium chloride solution and record what you see. Finally using a
dropper pull the waste out the solutions in the A wells and dispose of them in a container
provided by the teacher.
Results:
Ionic
Solutions
A
Ag+
NO₃-
B
Feᶟ⁺
NO₃ ‾
C
Cu^2+
NO₃ -
1
Na+₃PO₄
2
Na+
SO₄2-
3
Na+
OH-
4
Na+
Cl-
Yes, formed a
Yellow
precipitate
Yes, formed a
white
precipitate
Yes, formed a
Cloudy /
Milky
precipitate
None
Yes, formed a
Brown
precipitate
Yes, formed a
orange
precipitate
None
Yes, formed a
Cloudy-Milky
precipitate
None
None
None
None
Balanced Equations
A1: Na3PO4(aq) + 3AgNO3(aq) 3NaNO3(aq) +Ag3PO4(s)
A2: No Reaction
A3: AgNO3(aq) + NaOH(aq) AgOH(s) + NaNO3(aq)
A4: AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq)
B1: Fe(NO3)3(aq) + Na3PO4(aq) FePO4(s) + 3NaNO3(aq)
B2: No Reaction
B3: Fe(NO3)3(aq) + 3NaOH(aq) FeOH3(s) + 3NaNO3(aq)
B4: No Reaction
C1: AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq)
C2: No Reaction
C3: No Reaction
C4: No Reaction
Conclusion: In this lab different ionic solutions were combined the see which combinations
formed precipitates. These precipitate showed that a double replacement reaction was taking
place. We mixed Sliver Nitrate with Sodium Phosphate, sodium sulfate, sodium hydroxide, and
lastly we mixed the silver nitrate with sodium chloride. Then the steps were repeated but
instead of using the silver nitrate, iron (III) nitrate was used in one and in the other Copper (II)
nitrate was used. The results were as expected. The results that were produced were accurate
and somewhat precise. The purpose of this experiment was accomplished. They were
accomplished because the participants in this experiment now have a better understanding of
double replacement reactions. They also have a better understanding of how to write and
balance these types of chemical reactions.
Discussion: Some of the possible sources of error in the group might be that there was a
precipitate formed but all the group saw was a color changed and didn’t think that was really a
precipitate. This would have been a problem because a lot of the precipitate that were formed
was really shown by drastic color changes. For C-3 I got the wrong result due to a contaminated
experiment due water or an unknown in the micropipette because it was not cleaned well
enough. For the most part the group had accurate and precise results. The main trouble point
that caused the most error was the Sodium chloride; reason being is that the precipitate
formed was very difficult to tell it just turned a bit cloudy. This could have been because not
enough solution was mixed, it might have been contaminated, or it might have just supposed to
be that way.
Over all the group’s results came out so that there was a precipitate when there was
supposed a double replacement reaction happening and nothing happened when there was no
precipitate showing that there wasn’t a double replacement reaction going on.