NAME DATE PERIOD DOUBLE REPLACEMENT REACTION

COVERAGE PERIOD [SEE INSTRUCTIONS] S UMMARY OF
0 21415 PERIODO OCHENTA Y SEIS DE
0 32737 PERIODO CIENTO CATORCE DE SESIONES

0 43752 PERIODO OCHENTA Y CINCO DE
0 43752 PERIODO OCHENTA Y CINCO DE
19 PERIODO CIENTO TRES DE SESIONES ORDINARIAS

Name _________________________________________________________ Date _______________ Period _________

Double Replacement Reaction

Problem: How does a double-replacement reaction occur?

Background: Some of the most impressive chemical reactions are double-replacement reactions, also called ion-exchange reactions. In a double-replacement reaction, a clear solution of an ionic compound is added to a clear solution of another ionic compound. The positive ions of one compound react with the negative ions of the other compound to form a precipitate, a gas, or water. When a precipitate forms, the result can be very dramatic. The precipitate is an insoluble solid substance that my produce a sudden bright color in the remaining clear solution.

In this investigation you will observe a double-replacement reaction, perform a double-replacement reaction and interpret the results.

Demonstrations/Hypothesis: The teacher will prepare two clear solutions of hydrochloric acid and ammonium hydroxide. Both of these solutions evaporate very rapidly into the air. Hypothesize as to what you think will happen as these two ionic solutions come in close contact with each other in the air. Complete the following equation showing the products expected from this demonstration. Record your observations in Data Table 1.

HCl + NH₄OH  _________________ + ____________________

Materials:

Safety goggles 1 test tube & rack

2 100 mL beakers Sodium Iodide (Na⁺¹ I ^-1)

250 mL beaker Distilled Water

3 clean droppers Lead Nitrate (Pb⁺² NO₃^-2)

Procedure:

Place 1 dropper full of distilled water into the test tube.
Carefully measure out ½ dropper full of lead nitrate and drop into the test tube.
Hold the test tube out of the test tube rack.
Carefully measure out ½ dropper full of sodium iodide and drop into the same test tube.
Record your observations in the data table. Be very specific as to what you see.
Let the solution stand in the rack for 10 minutes. Record your observations. Be specific.
Do not spill contents of test tube down the drain! Your teacher will dispose it.

Observations:

Solution	Appearance	Final Results	Observations about reaction rate
Hydrochloric Acid
Ammonium Hydroxide
Lead Nitrate
Sodium Iodide

Analysis/Conclusions:

What ions were present in the lead nitrate solution? (Symbol and charge for each ion) ___________________________________________________________________________________________
What ions were present in the sodium iodide solution? (Symbol and charge for each ion)

___________________________________________________________________________________________

Write a balanced equation for the reaction that took place between the two substances

__________________________________________________________________________________________

How can you account for the change in appearance of the resulting mixture after the 10 minute waiting period? What happened?

___________________________________________________________________________________________

Compare and contrast the reactions between hydrochloric acid/ammonium hydroxide and sodium iodide/lead nitrate. Discuss the reactants, products and reaction rates.

______________________________________________________________________________________________

2 PERIODO CIENTO TREINTA Y CUATRO DE
2 PERIODO NOVENTA Y CUATRO DE SESIONES
2 PERIODO NOVENTA Y TRES DE SESIONES

Tags: double replacement, period, reaction, double, replacement