Quiz Reflection

Today I finally took the weekly quiz from last week. It was not that difficult nor that time consuming as there were not too many calculation problems. The quiz consisted mostly of concept and graph reading questions. This was one of the few quizzes/tests in which I actually had time to spare upon completing it.

http://www.gmlcpa.com/its-a-wrap-tax-season-2014/

Although the calculation portion of the quiz was pretty straightforward and not complicated, I suspect that the calculation problems on the test tomorrow will be a bit more detailed and complex. This means more practice for me :)

Some helpful links for studying:

http://www.nclark.net/MolarityPractice.pdf

https://www.youtube.com/watch?v=SXf9rDnVFao

https://chemistry11mrstandring.wikispaces.com/Stoichiometry+Calculations+Involving+Molar+Concentration

https://www.youtube.com/watch?v=KVZ_KS45rVg

http://chemcollective.org/activities/tutorials/stoich/solution_stoi

http://www.brainstretch.net/introChem/molesToMolarity/molarity/molarity.htm

Murder Lab Investigation, Day Two

Day Two consisted of weighing the dry filter paper that contained the solid from the reaction. The solid was a pea green powder.

After weighing the filter paper, we subtracted this mass from the mass of just the filter paper to figure out the mass of the solid. Then, we calculated the molarity of this substance and found out that it was roughly 0.07 M. To figure out the identity of the unknown substance, we knew that it must have been silver nitrate because when silver nitrate combines with sodium carbonate, it should make a solid, which is exactly what happened in lab. The 0.07 molarity matched Mr. Green's description, as he was found with traces of silver nitrate with a molarity between 0.05 and 0.15 M.

Murder Lab Investigation, Day One

The murder investigation lab seemed to be a very interesting lab. I love the idea of solving a a mystery while incorporating chemistry into it. It gives a taste of what forensic investigators do in reality. Today's task was combining an unknown solution with sodium carbonate in a beaker. Both reactants were clear, but when combined, the product was a milky white substance.

Then, we poured this substance into a funnel with filter paper inside an empty Erlenmeyer flask to collect any solid. While letting the liquid drip down into the flask, I noticed there was a sand-like substance forming inside the liquid, showing that the reaction definitely produced a solid. Thus, it can be inferred that the unknown substance is silver nitrate, due to the fact that it should produce a solid when reacted with sodium carbonate based on solubility rules.

Molarity

Unfortunately, these past few days in chemistry have been a bit of a whirlwind as I was absent from class Thursday and Friday for a field trip, which by the way I had a great time on! However, it was frustrating to be in utter confusion regarding what we learned in class. Today, I received some notes from my peers and learned molarity on my own and within a small group. It is not that complicated, and many molarity problems can be solved using commen sense, rather than using stoich. I still need to learn about dilutions and look over the aqueous solutions packet from last week.