Classifying Reactions Lab Report
In her advanced chemistry class, Ruby K. ('20) explored the categorization of chemical reactions.
Data Analysis:
In part 1, a combustion reaction occurred between solid magnesium and oxygen gas. I know it’s a combustion reaction because when the burning Mg strip was taken out of the flame, it glowed and radiated light. At the end, there was a white powder left over, which are the characteristics of a classic ionic compound, and we found the product to be MgO.
In part 2, a double replacement reaction occurred copper (II) chloride and sodium phosphate. I know it was a double replacement reaction because the two reactants were ionic compounds, both of which were aqueous solutions. At the end, the mixture became a solid and a liquid part, which we found we copper phosphate and sodium chloride, respectively.
In part 3, a single replacement reaction occurred between aqueous hydrochloric acid and solid magnesium. I know it’s a single replacement reaction because Mg is more reactive than H, which means that it could replace the H in the hydrochloric acid. The products of this reaction are solid magnesium chloride and hydrogen gas. The hydrogen gas makes sense because when we put a wood splint into the test tube, it made a “pop” sound.
In part 4, a double replacement and decomposition reaction took place between solid calcium carbonate and aqueous hydrochloric acid. The products of this reaction were water vapor, carbon dioxide gas, and solid calcium carbonate. In the reaction, there were bubbles rising to the top in the test tube, which must have been gases, and it was foggy in the test tube, which suggests that there was water vapor in it.
In part 5, a single replacement reaction occurred between aqueous copper (II) chloride and solid zinc. I know it was single replacement because Zn is more reactive than Cu, which means that it can replace the Cu in copper (II) chloride. The products were aqueous zinc chloride and solid copper, which makes sense because the reaction began and ended with an ionic compound and an element.
In part 6, a decomposition reaction occurred when the reactant solid ammonium carbonate was heated. Because there were no other reactants, and it didn’t show any signs of being a combustion reaction, I came to the conclusion that this was a decomposition reaction. The products of this reaction were carbon dioxide gas, water vapor, and ammonia gas. It was foggy in the test tube, which tells me that there was water vapor, and the burning wood splint went out when it was put in the test tube, which implies that there was carbon dioxide gas in the tube. There was also a strange smell at the end, which was the ammonia.
In part 7, an acid-base double replacement reaction occurred between aqueous sodium hydroxide and aqueous hydrochloric acid. This reaction started with one ionic compound and one acid, and ended with one ionic compound and one covalently bonded compound. The final products of this reaction were aqueous sodium chloride and liquid water. This makes sense because in a double replacement reaction there are two reactants, and two products, one of which is always water in an acid-base double replacement reaction.
In part 8, a combustion reaction occurred between aqueous ethyl alcohol and oxygen gas. I can tell it is a combustion reaction because the reactant ethyl alcohol is an organic compound, and one of the products that I could see was water. These are both good indicators that this is a combustion reaction, because in organic combustion reactions, the two products are always water gas and carbon dioxide gas. The only reactant I could see was the water vapor, so I can conclude that the other product of this reaction was carbon dioxide gas.
Error Analysis:
Some of the instructions for the reactions stated that you have to wait until the end of class to see the full results of the reaction. This could be a source of error for several reasons. One is that the wording “until the end of class” isn’t very explicit in how long to wait. Another is that is we did one of these experiments toward the end of class, we might not have seen the full results of the lab, which could have altered the chemical equations we created. One way to fix this problem is to specify a time to wait to finish the experiment, so you know when it’s done, and also how long the whole part will take.
Another possible source of error is that in almost every part of the experiment, the instructions asked you to put a “drop” of a solution into a test tube. A drop isn’t a very specific measurement, and even when we were doing the experiment, my partner and I commented that not all of the drops were the same size. The instructions also said to use a strip of magnesium ribbon in one experiment, which were not all evenly sized. Along with these two measurement issues, one of the instructions is also to use a “small spatula tip amount” of a substance, which isn’t very specific. These measurements that lack precision could have caused the reaction to occur differently if there was too much or too little of the substance. The problem is that I would never know if my chemical equations were wrong or right because although they are chemically sound, they are mostly based off of my own observations. One way to fix this problem is to measure the volume or mass of the reactants before putting them with the other reactants.
Another possible source of error in this experiment is that there could be more instructions about how to put the wood splint into the test tube. In my experience, sometimes the wood splint went out, and we weren’t sure if it was supposed to, or it seemed like it went out before it was even in the test tube. I would suggest making the instructions say that you should put the wood splint in twice, to make sure that the results you found were accurate and correct. If we hadn’t put another burning splint into the test tube, we might have hypothesized that there was a gas in an experiment, when there really wasn’t.
In part 1, a combustion reaction occurred between solid magnesium and oxygen gas. I know it’s a combustion reaction because when the burning Mg strip was taken out of the flame, it glowed and radiated light. At the end, there was a white powder left over, which are the characteristics of a classic ionic compound, and we found the product to be MgO.
In part 2, a double replacement reaction occurred copper (II) chloride and sodium phosphate. I know it was a double replacement reaction because the two reactants were ionic compounds, both of which were aqueous solutions. At the end, the mixture became a solid and a liquid part, which we found we copper phosphate and sodium chloride, respectively.
In part 3, a single replacement reaction occurred between aqueous hydrochloric acid and solid magnesium. I know it’s a single replacement reaction because Mg is more reactive than H, which means that it could replace the H in the hydrochloric acid. The products of this reaction are solid magnesium chloride and hydrogen gas. The hydrogen gas makes sense because when we put a wood splint into the test tube, it made a “pop” sound.
In part 4, a double replacement and decomposition reaction took place between solid calcium carbonate and aqueous hydrochloric acid. The products of this reaction were water vapor, carbon dioxide gas, and solid calcium carbonate. In the reaction, there were bubbles rising to the top in the test tube, which must have been gases, and it was foggy in the test tube, which suggests that there was water vapor in it.
In part 5, a single replacement reaction occurred between aqueous copper (II) chloride and solid zinc. I know it was single replacement because Zn is more reactive than Cu, which means that it can replace the Cu in copper (II) chloride. The products were aqueous zinc chloride and solid copper, which makes sense because the reaction began and ended with an ionic compound and an element.
In part 6, a decomposition reaction occurred when the reactant solid ammonium carbonate was heated. Because there were no other reactants, and it didn’t show any signs of being a combustion reaction, I came to the conclusion that this was a decomposition reaction. The products of this reaction were carbon dioxide gas, water vapor, and ammonia gas. It was foggy in the test tube, which tells me that there was water vapor, and the burning wood splint went out when it was put in the test tube, which implies that there was carbon dioxide gas in the tube. There was also a strange smell at the end, which was the ammonia.
In part 7, an acid-base double replacement reaction occurred between aqueous sodium hydroxide and aqueous hydrochloric acid. This reaction started with one ionic compound and one acid, and ended with one ionic compound and one covalently bonded compound. The final products of this reaction were aqueous sodium chloride and liquid water. This makes sense because in a double replacement reaction there are two reactants, and two products, one of which is always water in an acid-base double replacement reaction.
In part 8, a combustion reaction occurred between aqueous ethyl alcohol and oxygen gas. I can tell it is a combustion reaction because the reactant ethyl alcohol is an organic compound, and one of the products that I could see was water. These are both good indicators that this is a combustion reaction, because in organic combustion reactions, the two products are always water gas and carbon dioxide gas. The only reactant I could see was the water vapor, so I can conclude that the other product of this reaction was carbon dioxide gas.
Error Analysis:
Some of the instructions for the reactions stated that you have to wait until the end of class to see the full results of the reaction. This could be a source of error for several reasons. One is that the wording “until the end of class” isn’t very explicit in how long to wait. Another is that is we did one of these experiments toward the end of class, we might not have seen the full results of the lab, which could have altered the chemical equations we created. One way to fix this problem is to specify a time to wait to finish the experiment, so you know when it’s done, and also how long the whole part will take.
Another possible source of error is that in almost every part of the experiment, the instructions asked you to put a “drop” of a solution into a test tube. A drop isn’t a very specific measurement, and even when we were doing the experiment, my partner and I commented that not all of the drops were the same size. The instructions also said to use a strip of magnesium ribbon in one experiment, which were not all evenly sized. Along with these two measurement issues, one of the instructions is also to use a “small spatula tip amount” of a substance, which isn’t very specific. These measurements that lack precision could have caused the reaction to occur differently if there was too much or too little of the substance. The problem is that I would never know if my chemical equations were wrong or right because although they are chemically sound, they are mostly based off of my own observations. One way to fix this problem is to measure the volume or mass of the reactants before putting them with the other reactants.
Another possible source of error in this experiment is that there could be more instructions about how to put the wood splint into the test tube. In my experience, sometimes the wood splint went out, and we weren’t sure if it was supposed to, or it seemed like it went out before it was even in the test tube. I would suggest making the instructions say that you should put the wood splint in twice, to make sure that the results you found were accurate and correct. If we hadn’t put another burning splint into the test tube, we might have hypothesized that there was a gas in an experiment, when there really wasn’t.
