Names



Name _______________________________________________________ date _____ period _____

TYPES OF CHEMICAL REACTIONS

I. Purpose: To observe chemical reactions and identify reactants and products of those reactions. To

classify the reactions and write balanced equations.

II. Materials: zinc, mossy magnesium ribbon

sodium hydrogen carbonate 3 M HCl

0.1 M Pb(NO3)2 0.1 M KI

1.0 M HCl 1.0 M NaOH

phenolphthalein 3% H2O2

copper metal 3 small test tubes

burner watch glass

crucible tongs 6 test tubes

test tube holder wooden test tube rack

3 wood splints small graduated cylinder

III. Procedure:

A. Synthesis Reaction - Magnesium ribbon

1. a. Place a watch glass on your tabletop near your Bunsen burner. Using crucible tongs, hold a sample of magnesium ribbon in the burner flame until the magnesium ignites. You must hold the Mg in the hottest part of the flame – the tip of the inner blue cone. DO NOT LOOK DIRECTLY AT THE FLAME. HOLD THE BURNING MAGNESIUM AWAY FROM YOU AND DIRECTLY OVER THE WATCH GLASS. When the ribbon stops burning, put the remains in the watch glass.

b. Examine the remains of the burning magnesium. This product is magnesium oxide. Write your qualitative observations in the Data Table. The remains can be placed into the trash can.

B. Decomposition Reaction - NaHCO3 (You will be performing two separate decomposition reactions.)

2. a. Get a test tube from your instructor, do not use one from your plastic bin. Place approximately 1 inch of sodium hydrogen carbonate (NaHCO3) (aka sodium bicarbonate or baking soda) into the designated test tube. Note the appearance of the NaHCO3 sample in the Data Table.

b. Using a test tube holder, heat the NaHCO3 strongly for about 3 minutes. Remember that the open end of the test tube must be pointed away from everyone in the lab while heating. This will decompose the compound and produce sodium carbonate, carbon dioxide, and water. Light a wood splint with the flame from the burner and then extinguish the burner flame. Place the burning splint into the mouth of the test tube without dropping it into the test tube. If carbon dioxide gas is present, it will put the flame out. Note any changes in the appearance of the residue in the test tube. Since carbon dioxide is a predicted product of this reaction, the flame should go out.

c. Complete the data table for this part of the experiment. The remains can be put into the trash can.

3. a. Place approximately 20 drops of hydrogen peroxide (H2O2) in a test tube. Heat very gently on a low flame. This will decompose the H2O2 to produce water and oxygen gas (diatomic). Oxygen gas causes a glowing splint to continue burning. If you observe a gas forming, test for its identity by inserting a glowing wood splint into the mouth of the test tube. Light the splint and then blow out the flame, leaving a glow. This is a “glowing splint.” If the splint continues to glow, oxygen gas is present. Do not put the splint into the solution.

b. Complete the data table for this part of the experiment. The remaining liquid can be rinsed into the sink.

C. Single Replacement Reactions- Zn, Cu , Mg (You will perform 3 reactions to compare.)

4. a. Get three small test tubes and place them in your wooden test tube rack. Place a small piece of zinc, copper and magnesium in each of the different test tubes. Add 10 drops of 3M hydrochloric acid (HCl) to each of the three test tubes containing a metal. Observe and compare the rate of the formation of bubbles. Write your comparative results in the Data Table. Place each reaction’s waste in the designated waste container and rinse your test tubes thoroughly to use in the next step.

b. Place another small piece of magnesium into one of the regular test tubes and redo the reaction as described above for the purpose of testing for the formation of hydrogen gas. This reaction should be done in your wooden test tube rack. Using a test tube holder, hold an empty test tube over the top of the tube containing the Mg and the 3M HCl for approximately 20 seconds to act as a lid. Remove the top tube and quickly insert a burning wood splint into the mouth of the tube. A “pop” indicates the presence of hydrogen gas. If you do not hear a “pop,” there was not any hydrogen gas given off by the reaction.

D. Double Replacement (You will perform two separate double replacement reactions.)

5. Place about 1-2 drops of lead (II) nitrate solution in a test tube. Add 1-2 drops of potassium iodide solution to the test tube. Observe and record the results in the data table. After observation, the waste may be disposed of down the drain.

6. a. Place about 10 drops of 1.0 M hydrochloric acid in a clean test tube. Add 2 drops of phenolphthalein. Remember the cautions concerning the use of acids. Note the appearance of the solutions in the test tube.

b. Add about 12 drops of 1.0 M sodium hydroxide solution to the same test tube. Sodium hydroxide is a strong base. Be as careful when using bases as when using acids.) Note any changes in the appearance of the solutions in the test tube. Record your observations in the data table. After observation, the waste may be disposed of down the drain.

IV. Data and Results: Write all qualitative observations in the Data Table below.

| Reaction |Qualitative Observations |

|1. Synthesis | |

|Mg + O2 | |

|2. Decomposition | |

|NaHCO3 | |

|3. Decomposition | |

|H2O2 | |

|4. Single Replacement | |

|Zn + HCl | |

|5. Single Replacement | |

|Cu + HCl | |

|6. Single Replacement | |

|Mg + HCl | |

|7. Double Replacement | |

|Pb(NO3)2 + KI | |

|8. Double Replacement | |

|HCl + NaOH | |

V. Equations: Predict what you think was formed in each of the reactions below (these were the reactions for this lab). If there was no reaction, write “No Reaction.”

1. Synthesis

Mg + O2 (

2. Decomposition

NaHCO3 (

3. Decomposition

H2O2 (

4. Single Replacement

Zn + HCl (

5. Single Replacement

Cu + HCl (

6. Single Replacement

Mg + HCl (

7. Double Replacement

Pb(NO3)2 + KI (

8. Double Replacement

HCl + NaOH (

IV. Questions:

1. Complete the table: General Form for the Reactions:

|Type of Reaction | Reactants | Products |

|Synthesis: | Element + Element | Compound |

|Decomposition: | | |

|Single Replacement: | | |

|Double Replacement: | | |

2. The ability of a single displacement reaction to react is dependent upon the ability of the metal to displace the cation in the aqueous ionic compound. The more reactive the cation is, the more vigorous the reaction that results. Look at your comparative observations (Data Table) and your balanced chemical reactions (above) for the three single displacement reactions that were performed. These three reactions involved four cations. In the table below, rank these four cations. Then, explain how you were able to conclude this ranking.

|Ranking |Name of cation |

|1 highest | |

|2 | |

|3 | |

|4 lowest | |

3. Which of the tests you performed detected the presence of 3 different gases (H2, O2, and CO2 tests)?

4. Write the complete balanced equation that would result from the described reaction. Include states of matter for each chemical formula, s,l,g. Indicate type of reaction in the blank (DD = double replacement, SD = single replacement, S = synthesis, D = decomposition).

______ a. sulfur plus oxygen yields sulfur dioxide.

______ b. magnesium chloride plus sulfuric acid yields magnesium sulfate plus hydrogen chloride.

______ c. calcium carbonate yields calcium oxide plus carbon dioxide.

______ d. nitrogen plus hydrogen yields ammonia.

______ e. sodium plus water yields sodium hydroxide plus hydrogen gas.

______ f. lead (II) oxide yields lead plus oxygen.

______ g. copper plus silver nitrate yields silver plus copper (II) nitrate.

______ h. potassium chlorate yields potassium chloride plus oxygen.

______ i. calcium chloride plus silver nitrate yields silver chloride plus calcium nitrate.

______ j. oxygen plus hydrogen yields water.

______ k. sodium bromide plus chlorine yields sodium chloride plus bromine.

______ l. zinc acetate plus sodium phosphate yields sodium acetate and zinc phosphate.

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