Purpose
How do we determine the reaction type and write a balanced equation for chemical reactions?

Background Discussion
There are many kinds of chemical reactions and several ways of classifying them. One popular and useful method is to classify reactions into five major types. These are:
(1) synthesis, (2) decomposition, (3) single replacement, (4) double replacement, and (5) combustion. Most reactions can be put into one of these categories.

In a synthesis reaction, two or more substances (elements or compounds) combine to form a more complex substance. A decomposition reaction is exactly the opposite of a synthesis reaction. In a decomposition reaction, a compound breaks down into two or more simpler substances (elements or simpler compounds.)

In a single replacement reaction, one element in a compound is replaced by a more active element. In a double replacement reaction, the positive ions of two different ionic compounds can be thought of as “replacing each other.” Most replacement reactions (both single and double) take place in aqueous solutions containing free ions. In a double replacement reaction, one of the products must be removed from the solution as a precipitate, water, or an insoluble gas. A precipitate is a solid that is produced as a result of a chemical reaction in solution. As the precipitate separates from the solution, the solution appears cloudy.

In a combustion reaction a substance combines with oxygen, releasing a large amount of energy in the form of light and heat. If an organic compound (one that contains carbon) is a reactant, then the products of the combustion reaction are always carbon dioxide gas and water vapor.

Form a Hypothesis

If a chemical reaction has occurred, then __________________________________________

_____________________________________________________ may occur to indicate that a

reaction has taken place. Variables: Independent variable: The chemicals in which we are using.

Dependent variable: color change, pro physical properties

Equipment
Bunsen burner test tube rack tongs wood splint graduated cylinder matches string test tubes (2 small, 1 medium)

Materials iron nail magnesium ribbon, 5 cmcopper(II) carbonate 1M sodium carbonate 1 M copper(II) sulfate 1M barium nitrate
Procedure
Be sure to record observations before and after reactions take place.

A. Iron, copper(II) sulfate 1. Add about 3 mL of 1M copper(II) sulfate solution to a clean, dry, small test tube. Tie a string around the nail. 2. Dip the nail in the solution. After 10 minutes, pull the nail out. Place on a paper towel to dry.

Hint: In the product that contains iron, the iron has a charge of 2+

B. Magnesium, oxygen 1. Cut a piece of magnesium ribbon approximately 5 cm long. 2. Place an evaporating dish handy to the base of the burner. Light the burner. 3. Using tongs, hold the magnesium in the burner flame until the magnesium starts to burn. DO NOT LOOK DIRECTLY AT THE FLAME. Hold the burning magnesium away from you and directly over the evaporating dish. 4. When the ribbon stops burning, put what is left of the sample in the evaporating dish.

C. Barium nitrate, sodium carbonate 1. In a dry, clean, small test tube, place 10 drops of barium nitrate solution. 2. Add 5 to 7 drops of sodium carbonate.

Hint: The product containing carbonate is a precipitate.

D. Copper(II) carbonate 1. Use a weighing dish to measure about 2 grams of solid copper(II) carbonate. Transfer the copper(II) carbonate to a clean, dry, large test tube. 2. Gently shake test tube so the copper(II) carbonate is along the side, not packed in the bottom of the test tube. Using a test tube holder, heat the copper(II) carbonate strongly in a burner flame for 1 to 2 minutes, or until the sample completely changes color. Hold the test tube at a 45o angle but not pointing at someone. 3. Insert a burning wood splint in the test tube to test for the presence of carbon dioxide gas. (Carbon dioxide gas will put the flame out.)

Hint: Products are solid copper (II) oxide and carbon dioxide gas.

E. Calcium Oxide
Using a scoopula, obtain a small sample of Calcium Oxide and place into 2 test tubes. Record its physical properties 1. To one of the testtubes add 15 mL of water. 2. Add 15 mL of water to a 3rd test tube. Record its physical properties 3. Use pH paper to test the pH of each sample in each test tube (1. Calcium Oxide, 2 Calcium Oxide + water, and 3. Water) 4. Observe what happens to the pH of the water when it is reacted with calcium oxide.

F : Copper wire 1. Take a small piece of copper wire and hold it at one end using the crucible tongs.. Record its physical properties. 2. Place the opposite end of the wire into the hottest part of the flame in the Bunsen burner (the blue part) for 30 s.
Remove the wire and examine it. After the wire is cooled, scrape the surface with the edge of a scoopula

Cleanup
All solids should go in the trash can. All solutions in sink. The test tube containing the black powder should be rinsed out and then use the soapy water and test tube brush provided to completely clean test tube.

Data Table

Observations | Before reaction | After reaction | iron, copper(II) sulfate | Silver colored, and solid | Red colored, and rusted | magnesium ribbon | Silver colored, and solid | White colored and soft solid | barium nitrate, sodium carbonate | Murky liquid | Milky white colored, with precipitate | copper(II) carbonate | White colored, powder solid | White colored top, black colored bottom | calcium oxide | White colored, powder solid | Turned light green in normal water, turned dark blue in calcium oxide solution (PH 10) | copper wire | Bronze colored, solid wire | Black, Flame turned green |

Analysis and Conclusions

Analysis of data/Conclusion

For our first test, we were to investigate whether a copper sulfate solution, would affect a metallic nail, which would be placed within the solution. We did this by basking it for ten minutes. Firstly, we ensured that all of our materials were ready for use so that we could minimize our error. We also made sure that our stopwatch was ready for use, as our experiment depended on it. After the ten minutes were concluded, we found that the part of the nail that was revealed to the solution had turned red and rusty.

Our next test was for magnesium ribbon. The substance was silver and solid. We were to do the experiment by placing magnesium ribbon over a Bunsen burners flame using tongs. Before commencing the experiment we ensured that our materials were both in order as well as clean. After subjecting the magnesium ribbon to the flame, we found that it let off a large amount of heat and light energy. We could tell because, once the ribbon was subjected to the flame, it burst into a bright white light. This tells us that the reaction consisted of both heat and light. This is known as a combustion reaction.

After this, we tested a barium nitrate solution. The solution was liquid, but seemed very murky as well. We cleaned our materials and started the experiment. The fist step was to add sodium carbonate to the test tube. After this reaction occurred, we found the solution to change in color. The color was not a curdy white, instead of murky. We also found that the solution as given a precipitate, of white color.

The next test consisted of copper carbonate. However, instead of using copper carbonate, we used calcium carbonate, as we did not have copper. We were to put the compound powder within a test tube and then keep it over the flame of a Bunsen burner using tongs, for around two minutes. We ensured that our materials were both in order and cleansed before commencing the experiment. After two minutes of holding the test tube over the Bunsen burner, we found that there was a large color change. The top of the test tube had become black, and the bottom remained white. After placing the wooden splint in the test tube, we found that the carbon dioxide did in fact put out the flame. From this we can deduce that this was a syntheses reaction, as the two reactants created carbon dioxide.

The next experiment was for calcium oxide. We were to use a test tube of water as well as a test tube of copper oxide solution, to conduct the experiment. We had to place a PH paper in the various test tubes and tell the difference in color, as well as PH level. We found that within the test tube with calcium oxide solution, the solution had turned a dark blue, which we had identified to be approximately PH10. The water had turned green. This means that it was PH7, and was stable.

The final experiment was for copper wire. We were to use a thin copper wire, and place it over a flame, emitted from a Bunsen burner. We found that the flame had turned from a blue to green, which

Part | Balanced equation | Type | A | | | B | | | C | | | D | | | E | | |
Draw Conclusions 1. Name five types of chemical reactions. * Syntheses Reaction * Decomposition Reaction * Single replacement Reaction * Double Replacement Reaction * Combustion reaction 2. What is a reactant in a chemical reaction?
A reactant is the compound, which undergoes change during a reaction, and creates the product of the reaction. 3. What is a product in a chemical reaction?
The product of a chemical reaction is the substance, which is created, after the reactant had undergone change. 4. Name four ways you can tell a chemical reaction has taken place. * Heat/light energy output * Precipitation * Change in color * Change in form 5. What does the symbol mean in a chemical equation?
This symbol differs the reactants from the product. 6. Why must chemical equations be balanced?
Chemical equations must be balanced, so that each element in the reaction can be satisfied. If they are not, then they will not react. However if they are than the will and will be balanced.

Conclusion:

During this experiment, we were mainly trying to find out what kind of reactions occurs, among various compounds, and solutions. The experiments were quite simple, however, they told us a lot about what kinds of reactions take place in a variety of situations. The first test showed us how various solutions can affect different metals. The experiment for magnesium displayed a combustion reaction as it gave off a large amount of heat and light energy. The next experiment showed us what kind of reactions happen in solution situations, as the subject was liquid. The color had changed, and there was a precipitate. All of these experiments showed us a large amount of ways in which reactions can occur.
I learned much about various reactions, as well as equation balancing during these experiments. Firstly I learned about the five main types of reaction with an in-depth practical approach, which I personally feel, allowed me to understand the reactions better than I ever had before. I feel that the experiments also helped me in balancing equations. This is because, prior to the experiment, we had simply balanced equations that we’d found in a work sheet, or in our textbook, but this felt like a practical in the moment approach, which in my opinion, made it a lot more fun.

These reactions most certainly take place in our day-to-day activities. Firstly, when we use the stove too cook food we generally place oil in the pans where we cook, this causes a combustion reaction, and hence, the food can be cooked. Or, when you are baking a cake. Baking soda is added to the cake mix, which adds acidic substances to the recipe. Reactions especially occur in illnesses or in disease. For example, kidney stones are formed using a synthesis reaction. Synthesis reactions also occur in the rusting of iron, just as we saw in our experiment. Air coolers or warmers, also combust natural recourses to make the environment either cooler or warmer. This is known as a combustion reaction