This document describes a lab experiment on precipitation reactions. Students will observe precipitation reactions by mixing aqueous solutions of cations and anions in test tubes. They will identify which two cations form the most precipitates. The materials needed are listed. The procedure involves placing solutions in test tubes and observing any color changes or precipitate formation. Examples of double displacement reactions that form precipitates are provided, such as the reaction of Pb(NO3)2 and NaCl forming an insoluble PbCl2 precipitate. Safety precautions are emphasized.

1. CHEMISTRYBryan Terán & Andrea Alonso

2. Precipitationin DoubleDisplacementReactionsIn this lab activitywe have to observe precipitation reactions by mixing aqueous solutions of cations and anions. We have to Indicate which 2 cations form the most precipitates.

3. Materialsfor the practisePb(NO3)2KINaOHNa2CO3AgNO3KNO3CaCl2NaClFeCl3CuSO4Test tubesTest tubes rack

4. Procedure1- Place 21 clean test tubes in a test tube rack2- Add 6 drops of the solution indicated at the worksheet to 7 clean test tubes3- Add 6 drops of AgNO3, Pb(NO3)2and CaCl2solution to everytest tube

5. EXEMPLES4- Observe and record information and color of precipitates formedFor example … Pb ( NO 3)2 reaction with NaCl to form PbCl2 and Na(NO3)

6. But one of the new compounds are not soluble and precipitates are formedThe Cl- ions aren’t soluble with Pb++.Pb(NO3)2 + NaCl PbCl2 + NaNO3white

7. More exemples…This reaction between AgNO3 and KI, forms AgI and KNO3.The Ion I- isn’t soluble with Ag and forms precipitates.

8. At the end…After mixing all the compounds and balance the reactions……5- We must tidy and clean all the materials 

9. REMEMBER! We must not make any reaction without the supervision of our teacher FELISA PINILLA.

10. VERY IMPORTANT!!And even more important,-not to ingest any material…