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Precipitation Reactions

In this video we'll show you how to use the inorganic lab:

  1. To start this activity, click this link for Precipitation Reactions. The lab will load in a new tab. Click back to this tab to read further instructions and complete the questions below. You can follow along with the instructions below in the Procedures tab in the lab.

 

  1. React each of the cations (across the top row) with each of the anions (down the left column) according to the data table using the following procedures:

    a. Drag a test tube from the box and place it in the clamp in the ring stand (or double click it in the box to position it correctly). You can then click on the bottle of Ag+ ion solution on the shelf to add it to the test tube.

     

    b. Click on the Divide button (the test tube next to the hotplate on the front of the lab bench) four times to make four additional test tubes containing Ag+. With one test tube in the clamp and four others in the blue rack, click on the Na2CO3 bottle in the reagent area on the bench and observe what happens in the Live Data window. Record your observation in the table. If the solution remains clear, record NR for no reaction. Drag this test tube to the red disposal bucket on the right.

     

    c. Drag a second tube with Ag+ from the blue rack to the clamp. Add Na2S, record your observations and discard the tube. Continue with the third, fourth and fifth tube, but add NaOH, Na2SO4, and NaCl respectively. Record your observations and discard the tubes. When you are finished, click on the red disposal bucket to clear the lab.

     

    d. Repeat steps a-c for five test tubes of Pb2+ and Ca2+.  Record your observations in the data table. If no precipitate forms write NR for no reaction.

    You will find that a few of these formulas may not be what you'd expect from the solubility tables in your textbook. Some of the variations are due to the fact that these are low concentration prepared solutions that include water. Acidity, temperature and speed of reaction all affect the results you see. These are all actual images taken under identical conditions in our labs.

      Data Table

COLORS

AgNO3   (Ag+)

Pb(NO3)2   (Pb2+)

Ca(NO3)2   (Ca2+)

Na2CO3  ((CO3)2-)

A

F  

K  

Na2S  (S2-)

B

G  

L  

NaOH  (OH-)

C 

H  

M  

Na2SO4  ((SO4)2-)

D  

I  

N  

NaCl  (Cl-)

E 

J  

O  
  1. What happens in grid space d? What other reactions give similar results? Is it necessary to write an equation when no reaction occurs? Explain.  

 

  1. Write balanced equations for all precipitation reactions you observed. If no reaction was observed write "NR".

A.

B.

C.

D.

E.

F.

G.

H.

I.

J.

K.

L.

M.

N.

O.

 

  1. Write balanced net ionic equations for all precipitation reactions you observed. If no reaction was observed write "NR".

A.

B.

C.

D.

E.

F.

G.

H.

I.

J.

K.  

L.

M.  

N.

O.