Chem Blog #2

This past week, we learned a lot about reactions. We began by balancing basic equations and learned that we need to balance equations because of the Law of Conservation of Mass which states that mass is neither created nor destroyed. This idea then lead into the concept that there are five different types of reactions that we can determine by simply seeing the reactants of an equation. The five types include synthesis, decomposition, single replacement, double replacement, and combustion. Synthesis is where two reactants combine to make one product, decomposition is where one reactant splits to make two products, single replacement is when a negatively charged ion in a compound is replaced by another negatively charged ion or a positive replaces a positive, a double replacement reaction is where both the positive and the negative switch places, and a combustion (for this unit) is when a compound of carbon and hydrogen reacts with oxygen to make water and carbon dioxide.
 We then conducted an experiment in which we observed multiple reactions between substances. We wrote down the beginning equations and then after the reaction we tested the products with lipid papers to determine where on the pH spectrum they were and burning/glowing splints to test what the gas given off by the product was. If the lipid paper turned blue, we knew it was a base and if it turned red we knew it was an acid. This helped up determine the resulting compounds. If a glowing splint reignited, we knew the gas was oxygen, if a burning splint went out, we knew the gas of carbon dioxide, and if the burning splint made loud popping noises, we knew the gas was hydrogen. We then labeled which reaction occurred. We also, as a class, observed the reaction that takes place between copper and silver nitrate.

We then went more in depth with the single replacement reactions. We learned that certain elements are more reactive than others. Therefore, sometimes single replacement reactions cannot occur. We conducted a lab in which we placed different metals in aqueous solutions of different metals and observed when a reaction did or did not occur. By looking at our results, we were able to deduce that magnesium was very reactive in comparison to the other metals, and that copper was not very reactive in comparison.
I participated well in the learning process this week. I was gone for a few days, but my lab partner caught me up on many of the main ideas of the days that I missed so I don't have many questions. One question that I do have is- What other kinds of combustion reactions are there? I think I would rate my understanding of the ideas from class this week as a nine out of ten. I am pretty confident that I comprehend most of what had happened, but there can always be places where I'm not 100% sure I know everything. I think I still need to work on remembering the names of some of the chemical reaction types and exceptions to the single replacement reactions.