Eliazar Foreste – Lab Report
CHM 2025 L
The Classification of Chemical Reactions
In this laboratory investigation, we were performing experiments and balancing reactions equations in order to classify chemical reactions. Chemically, classification is the act of classifying a reaction after a chemical reaction. The results of the experiment and analysis of the reactions equations will help us to identify whether a reaction will be a combination, decomposition, combustion, double and single replacement. For instance, the reaction that has only one product species will be identified as a combination and one reactant species a decomposition. The reaction that produces a flame will be considered a combustion reaction. We will be classified a reaction double replacement precipitation if one product is an ionic solid, and both reactants are ionic solutions. A double replacement neutralization will be determined if the reactants are an acid and a base that yield to water and a salt. A reaction will be considered a single replacement reaction if a solid reactant metal disappears and a different solid metal appears or a solid metal reactant disappears and gas bubbles will appear.
Materials and Methods
Reaction 1: We collected two test tubes and placed them on a test tube rack. In one test tube, we dissolved small amounts of calcium chloride into the water. We placed a small amount of water in the other test tube and dissolved sodium carbonate into it. After dissolving it, we combined the two solutions. We observed the reaction and recorded the chemical reaction. Reaction 2: We placed two graduated cylinders on the desk and filled both with 25 mL of hydrogen peroxide containing a small amount of dish soap. Then, we added different sizes of cut potato to each graduated cylinder. We watched the reaction, compared how fast the reaction occurred in each graduated cylinder, and disposed of the chemical materials in the sink and the cut potatoes in the trash. Reaction 3: We used two test tubes to dissolved separately two solids. We dissolved Copper (II) chloride into the water in one test tube and sodium phosphate in the other test tube. After dissolving the two solids, we then combined the two substances in a small beaker. We watched the reaction, marked down the chemical reaction and dumped the chemical substances into the proper container. Reaction 4: We performed this experiment under the fume hood by using a crucible tongs to hold a steel wool. We touched the steel wool on the battery in order to observe a reaction. After burning the iron, we recorded the reaction and discarded the steel wool into a beaker of water under the fume hood. Reaction 5: First, we took the temperature of the hydrochloric acid. Then, we added the hydrochloric acid to the magnesium metal. Since this reaction was so hot, we avoided touching the dish. After the reaction, we took the temperature of the hydrochloric acid again. We documented the chemical reaction and disposed the chemical materials into a metal waste container. Reaction 6: We dissolved small amounts of copper (II) sulfate into a small beaker. After dissolving it, we added it to a very small piece of zinc. We carefully observed the reaction, recorded the chemical reaction, and threw away the chemical waste into the appropriate waste container. Reaction 7: First, we dissolved a small amount of magnesium hydroxide into a beaker and added red cabbage indicator to it. After dissolving the substances, we then added small amounts of hydrochloric acid. We watched the reaction closely, wrote down the chemical reaction, and disposed of any waste materials in the designated waste container. Reaction 8: We poured a small amount of silver nitrate solution onto a piece of copper. We allowed it to react for at least 5 minutes. Then, we recorded the reaction and got rid of the silver waste. Reaction 9: We used one full-size scoop of solid calcium carbonate. We placed the calcium carbonate in a sealed baggie and added red cabbage indicator and vinegar to it. We observed the reaction, recorded the reaction, and discarded the waste in sink and trash. Reaction 10: First, we used a disposable pipet and placed 5 mL of ethanol into an evaporating dish. Next, we used a disposable pipet and placed drop by drop very small amounts of saturated calcium acetate. We added 6 drops of saturated calcium acetate instead of 5 drops because there was an error. We swirled the evaporating dish after each drop and allowed few seconds for a gel to form. We stopped the addition of the calcium acetate when we observed the gel formation. Then, we ignited the gel substance with a lighter in the fume hood. While the ethanol was burning, we sprinkled one scoop of boric acid on the burning substance for a colorful observation. We used a crucible tongs and carefully placed a watch glass over the evaporating dish to put out the flame. We documented the observation and after the evaporating dish was cooled down we threw away the waste materials.
Reaction 1: In the reaction between calcium chloride and sodium carbonate, we observed a white solid substance from the chemical reaction. Reaction 2: we noted a milky liquid and bubbles in both graduated cylinders. We saw fewer foams and slower reaction in the graduated cylinder with the small cut of potato and more foams and faster reaction in the graduated cylinder with the larger cut of potato. Reaction 3: We saw a blue solid and jelly liquid in the reaction. Reaction 4: For this reaction, the steel wool burned when we touched it with the negative and positive poles of the battery. Reaction 5: We noted the release of a gas or vapor. We also observed that the temperature of the hydrochloric acid was increased from 23 degree Celsius to 33 degree Celsius. Reaction 6: We noticed that the zinc changed from a silver color to a rusty black color. Reaction 7: We watched that the solutions turned from purple to red clear. Reaction 8: We noted that the copper changed to a silver color after the chemical reaction. Reaction 9: We discovered this reaction produced bubbles/gas and turned to a milky blue substance, which was different to the reactions that yielded to a salt and water. Reaction 10: We noted the formation of a gel after adding 5 drops of calcium acetate into the ethanol. While the ethanol was burning, we sprinkled a little boric acid and observed a green flame. We also noticed that the flame was turned off when we put a watch glass over the evaporating dish. The following are the ten balanced chemical equations for the reactions:
Reaction 1: CaCl2 (aq) + Na2CO3 (aq) ? CaCO3 (s) + 2 NaCl (aq)
Reaction 2: 2 H2O2 (aq) ? 2 H2O (l) + O2 (g)
Reaction 3: 3 CuCl2 (aq) + 2 Na3PO4 (aq) ? Cu3 (PO4)2 (s) + 6 NaCl (aq)
Reaction 4: 4 Fe (s) + 3 O2 (g) ? 2 FeO3 (s)
Reaction 5: Mg (s) + 2 HCl (aq) ? MgCl2 (aq) + H2 (g)
Reaction 6: Zn (s) + CuSO4 (aq) ? ZnSO4 (aq) + Cu (s)
Reaction 7: 2 HCl (aq) + Mg (OH) 2 (aq) ? MgCl2 (aq) + 2 H2O (l)
Reaction 8: Cu (s) + 2 AgNO3 (aq) ? Cu (NO3)2 (aq) + 2 Ag (s)
Reaction 9: CaCO3 (s) + 2 C2H4O2 (aq) ? Ca (C2H3O2)2 (aq) + H2O (l) + CO2 (g)
Reaction 10: C2H6O (l) + 3 O2 (g) ? 2 CO2 (g) + 3 H2O (l)
The results and the balanced reactions equations helped us to determine the type of reaction. The white solid substance we observed in reaction 1 was the precipitate CaCO3. Therefore, this reaction is a double replacement precipitation reaction. For reaction 2, hydrogen peroxide decomposed and produced water and oxygen gas. It is a decomposition reaction. Reaction 3 is also a double replacement precipitation reaction. The precipitate Cu3 (PO4)2 was formed in the reaction. For reaction 4, the burning of the steel wool indicated that the reaction is a combination reaction. The observation of the gas release and the change in temperature of HCl led us to classify reaction 5 as a single replacement reaction. We also found that reaction 6 is a single replacement reaction in which the copper displaced the zinc. A salt and water were formed by the reaction between hydrochloric acid and magnesium hydroxide. As a result, we identified this as a double replacement neutralization reaction. We classified reaction 8 as a single replacement reaction because we noticed that silver displaced copper and formed Cu (NO3)2 and the solid silver. A double replacement gas-forming reaction was observed for the reaction between calcium carbonate and acetic acid. For reaction 10, the formation of the gel and the burning of ethanol produced a flame when we sprinkled a little boric acid on it. This led us to identify this reaction as a combustion reaction. Finally, we were amazed to perform this wonderful lab experiment. We hope to perform more in the future.