NAME: _________________________________ CHEMISTRY I CHAPTER 6 TYPES OF CHEMICAL REACTIONS LABORATORY Most reactions can be classified into one of four major categories: 1.

Synthesis: these are reactions in which atoms and molecules join together to produce larger molecules. An example is the combustion of sulfur to form sulfur dioxide: S(s) +

2.

O2(g)

------


Decomposition: these reactions are just the opposite of addition reactions. An example is the decomposition of carbonic acid: H2CO3(aq) -----


3.

H2O(g) + CO2(g)

Single Replacement (Displacement): these reactions involve a change of partners. An example of a displacement reaction is the liberation of bromine from calcium bromide by the action of chlorine: CaBr2(aq)

4.

SO2(g)

+ Cl2(g)

----


CaCl2(aq)

+

Br2(g)

Double Replacement (Displacement): these reactions involve a joint exchange of partners, as in the precipitation of silver chloride when solutions of silver nitrate and sodium chloride are mixed: AgNO3(aq) +

NaCl(aq)

----


AgCl(aq)

+ NaNO3(aq)

In this experiment you will study six different chemical reactions. You will identify some of the products and then classify each reaction as one of the four types. PROCEDURE: (record all observations in the data section). Use the larger test tubes in all parts. PART I:. 1. Place an aluminum soda can tab in a test tube and cover it with a solution of copper (II) chloride. a. Leave the tab in the test tube for about 30 minutes (move on to another part of the procedure). b. After 30 minutes, remove the soda tab from the test tube and examine it. c. Make your observations in the data section. d. Answer the questions listed in the data section for Part I of the procedure.

PART II: 1. Place sodium sulfate solution in a test tube to a height of about 3 cm. 2. Add about 3 mL of the barium chloride solution to the test tube. 3. Make observations immediately in the data section. 4. Make observations 20-30 minutes later also. 5. Answer the questions listed in the data section for Part II of the procedure. PART III: 1. Using crucible tongs, hold a 5 cm piece of copper wire in a burner flame for about 2 minutes after turning red. 2. Remove the copper from the flame and examine it – DON’T TOUCH IT --- IT’S HOT!! 3. Return the cooled wire to your teacher. 4. Make observations in the data section. 5. Answer the questions listed in the data section for Part III of the procedure. PART IV: 1. Using a triangle file, file away small notches in the edge of a penny. 2. Place the penny in the smallest beaker from your lab drawer. 3. Add enough dilute HCl to cover the penny in the beaker. 4. Label the beaker with tape and your name. 5. Place the beaker in the fume hood and leave it overnight. 6. Day 2: Look at the penny in the HCl in the beaker. 7. Make observations in the data section. 8. Answer the questions listed in the data section for Part IV of the procedure. PART V: 1. Pour hydrogen peroxide into a test tube to a height of about 3 cm. 2. Add a few crystals of manganese dioxide. 3. Manganese dioxide does not actually participate in this reaction, do not include it in the equation. a. The only reactant is hydrogen peroxide. 4. Make observations in the data section about what happened when you added the manganese dioxide. 5. Insert a glowing splint into the mouth of the test tube. a. Make observations in the data section. 6. Answer the questions listed in the data section for Part V of the procedure. PART VI: 1. Place about 5-6 crystals of copper (II) sulfate pentahydrate in a clean, dry test tube and heat until no further change is observed. a. Make observations and answer questions in the data section. 2. Once the test tube is cool, add 3 drops of water. a. Make observations in the data section.

DATA: PART I: 1. Do you observe any change in the appearance of the soda tab? _______________ 2.

If so, what is the change? ___________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________

3.

Do you observe any change in the appearance of the copper (II) chloride solution? _____

4.

If so, what is the change? ___________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________

PART II: 1. What do you observe right away? ____________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ 2.

What do you observe after 20-30 minutes?_____________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________

3.

If one of the products is sodium chloride (which is soluble in water), what is the other product? __________________________________

PART III: 1. What do you observe? _____________________________________________________ _______________________________________________________________________ _______________________________________________________________________ 2. With what did the copper combine? ______________________________________ PART IV: 1 What do you observe? _____________________________________________________ _______________________________________________________________________ _______________________________________________________________________ PART V: 1. What do you observe? _____________________________________________________ _______________________________________________________________________ _______________________________________________________________________

2.

What do you observe when you insert the glowing splint into the mouth of the test tube? _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________

3.

Water is one product of this reaction, what is the other product? ____________________ _______________________________________________________________________

4.

The manganese dioxide used in this experiment is a catalyst. a. What is a catalyst? __________________________________________________ _________________________________________________________________ _________________________________________________________________ b.

Is this catalyst a reactant in the reaction? ________________________________

PART VI: 1. What do you observe in the upper part of the test tube? ___________________________ _______________________________________________________________________ _______________________________________________________________________ 2.

What do you observe in the bottom part of the test tube? _________________________ _______________________________________________________________________ _______________________________________________________________________

3.

What is the substance remaining in the test tube after the heating? _________________ _______________________________________________________________________

4.

What do you observe after adding the 3 drops of water? __________________________ _______________________________________________________________________ _______________________________________________________________________

CONCLUSION: 1. Write the word equations that describe the chemical reactions taking place in parts 1 through 6: a.

Part I: __________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________

b.

Part II:__________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________

c.

Part III: _________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________

d.

Part IV:_________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________

e.

Part V:__________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________

f.

Part VI:_________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________

2.

Identify which type of chemical reaction is illustrated in each part of this experiment:

a.

Part I: __________________________________________________________________

b.

Part II: _________________________________________________________________

c.

Part III: _________________________________________________________________

d.

Part IV: ________________________________________________________________

e.

Part V:__________________________________________________________________

f.

Part VI: _________________________________________________________________

3.

Write the balanced chemical equation for each reaction taking place in parts 1 through 6.

a.

Part I:

b.

Part II:

c.

Part III:

d.

Part IV:

e.

Part V:

f.

Part VI: