Unit Test

    Today we took our unit test over stoichiometry. It was only 12 questions which is good, but also kind of scary because it is easier to fail. I feel like I knew what I was doing throughout the test and that I did not get any answers that were completely unreasonable. Hopefully grades go in school. On the bright side, we are now officially done with our last unit of the semester.

Helpful Links!

Below are some links that will hopefully make this unit a little easier. Especially since our unit test is tomorrow.

Magic Number Stoichiometry

Practice Quiz

Dimensional Analysis Review

Balancing Equations Review

Bozeman Science Stoichiometry

Bozeman Science Limiting Reactants and Percent Yield

Copper (II) Chloride and Iron Lab

Over the past several days, we have completed a lab involving copper (II) chloride and iron. We placed an aqueous solution of copper (II) chloride in a baby food jar with an iron nail. In the end, we created iron (III) chloride. Below are pictures as the lab progressed and as we drained our jar of everything but our copper formed.

Day One 

Day Two

Day Three

Weekly Quiz

Today we had our weekly quiz over our new unit, stoichiometry. From the two class lectures we had, the unit did not seem that difficult. I followed along with the examples that were worked in class and did extra practice. I felt confident with all of the material and while I was working out the problems on the quiz, I maintained that confidence. I did all of my calculations and thought my answer looked right. Then, I looked at the answer choices. None of them were the answer I had gotten with my calculations. This did not happen with just problem, but seven of them. I carefully retyped in my calculations into my calculator hoping to catch my mistakes, but I came out with the same answers. I redid all of my numbers in the calculations and still had no luck in figuring out my mistakes. Hoping for the best.

Solubility Rules

Below is a chart to help you determine the solubility of certain compounds. These rules only apply for double replacement/ precipitate reactions. Below the chart are some helpful links.


Practice Quiz
Mnemonic Tricks Video
Solubility Rules Explanation Video

Unit test

     Today we took our test for our chemical reactions unit. I feel like I did not do too badly on this test. I am certain that this unit test went better than the last unit test (chemical composition). This time around I feel like I knew more material on the test and had plenty of time to finish it. I only felt unsure about a handful of questions, but felt comfortable with the material overall. I tried to read every question carefully, but I still feel like I may have forgotten a small deatail and messed up a lot of questions. Hopefully that feeling does not turn out to be true.

Activity Series of Metals Lab

In this lab, we combined 4 metals (Pb, Cu, Ca, Mg, Sn, and Zn) with 4 different solutions (H20, HCl, CuSO4, and AgNO3) to observe the reactions taking place. Below are a few pictures of our products of the reactions.

What is an Activity Series?

Oxidation Numbers

The rules for determining oxidation numbers are:

• Each atom in a pure element has an oxidation number of zero.
• For monatomic (metal cations) ions, the oxidation number is equal to the charge on the ion.
• Fluorine always has an oxidation number of -1 in compounds with all other elements.
• Cl, Br, and I always have an oxidation number of -1 in compounds, except when combined with oxygen or fluorine.
• The oxidation number of H is +1 except in compounds with metals (hydrides) when H is -1
• The oxidation number of O is -2 except in peroxides when O is -1
• The algebraic sum of the oxidation number for the atoms in a neutral compound must be zero. In a polyatomic ion, the sum must be equal the ion charge.

Remember:

• Oxidation numbers can be fractions
• Oxidation numbers and charges are not the same thing, nor are they written the same
• +2 is oxidation 
• 2+ is charge

Oxidation Number Practice Quiz
More information

Chemistry Lab

Last week we did a lab that involved mixing different chemicals together and observing any reactions taking place. Overall, it was a simple lab, but it was cool to see the different reactions happening. After our data was collected, we found the molecular and complete ionic formulas of each of the successful reactions. Below are pictures of all of the reactions. As you can see, some combinations of chemicals had no change, some caused a slight color change, and some caused a drastic color change.

Molecular vs Empirical Formulas

During this unit, we learned to differentiate between molecular and empirical formulas. We learned that empirical formulas are the lowest whole number ratio of elements in a compound while molecular formulas are the whole number multiple of the empirical formula. Remember the empirical and molecular formulas of a compound can be the same. Here are some websites that go more in depth.

Molecular vs. Empirical Formulas

How to find Molecular Formula

How to Find Empirical Formula

Practice Quiz

Finally Made it into Lab!

So today, my partner and I both passed the pre-lab quiz for the first time all year. This means we got to complete our first lab! As for our class overall, there were four total lab partnerships that passed. That is quadruple our original record. The lab was about figuring how to find the formula of a chloride. We did this by measuring the mass of the empty beaker, the beaker with the piece of zinc, and the beaker with the zinc chloride compound. The first picture shows the piece of zinc in the HCl in the early stages of heating, so the zinc has not dissolved much yet. The second picture shows the end product after heating the zinc and HCl. The third picture shows my calculations to how I determined the formula of the chloride.

Well That Was Rough...

Yesterday we took our first quiz for this unit, and it was rough. During the quiz, I could tell that I was forgetting to look for a lot of things, such as the diatomics, so I was not expecting to get a good score.  Quiz grades were entered in the gradebook this morning and I was not surprised. On the brightside, it was only 17 questions, so it did not completely cause my grade to plummet, but that means that with few questions, each missed question dramatically affected the quiz score. Hopefully the unit test next week will go better, I just need to review. Below are some helpful links.

The Seven Diatomics

Different Diatomic Acronyms

Solving Problems Using Moles

Yesterday in class we learned how to solve problems using moles as a unit of measurement. Basically, this lesson was an exapansion on dimensional analysis, a skill which we learned last unit. The picture below serves as a guidance to find the right answer when converting between grams, moles, representative particles, and/or the volume of gasses.

Pretest

Today we took the prestest for our new unit. While taking the test, I barely knew any of the material. Usually during pretests, I can gather a vague idea of what is going on, but this time I could not figure out almost anything. My score of a 31% reflects these thoughts of unfamiliarity with this unit's content. It looks like the unit is a lot of calculating numbers, which is fairly easy, so I hope this unit is not that hard.

Last Meal Project

While completing my Last Meal Project, I referred to the charts below to help me. After converting the imperial unit to the metric measurement, I used dimensional analysis as explained a few posts back.

Last Meal Project Party

On Friday, we finished our week off with everyone bringing in one of their recipes from the Last Meal Project we had completed. It was nice to have an hour to relax and eat the food everyone brought in to share. The only downside was the majority of people brought in desserts, so you could not taste everything without getting sick. I think I only got to eat maybe a third of the projects brought in. Out of the ones I had the opportunity to try, they were very good, and I assume the rest were tasty too. I feel like the dishes that stood out the most were the ones that were not desserts. For example, I tried some pasta salad, sushi, and a couple different dips that I enjoyed very much. I am not saying that any of the desserts did not stand out, however. One of the desserts brought in were doughnuts that looked like monsters. They even had the plastic fangs in the middle! Also, the Reese's cupcakes with a peanut butter cup in the center and the Ande's Mint cupcakes were among my favorite desserts. It was nice to see all of the effort my fellow classmates put into their projects. The picture below shows two of the cupcake dishes brought in.

Test Grade Anticipation

On Thursday we took our unit test and I feel like I did somewhat well. A lot of the test was over the last section we learned, so it was still fresh in my mind. It was mostly just calculating numbers which I find easy. The most difficult part was remembering to round the answer to the correct number of significant figures, but the test was multiple choice, so I feel like I caught any mistakes I made while calculating. I was hoping the grade would be in now, but they are unfortunately not. This weekend was a busy weekend, so I expect them to be in this week because it should not be as hectic. I feel like I got a decent grade, but I guess we will have to wait and see.

Dimensional Analysis

Yesterday we learned about dimensional analysis. Dimensional analysis is used to convert one quantity into a different quantity. Below is an example:


 The quantity given was 10 m/s and they wanted to know what that quantity would be if it were converted into km/hr. Notice that the same units are placed diagonally from each other, so they cancel out each other when multiplied.

Using cubed and square unit is a similar process, just a little more complicated. For example, we are going to convert 56 in^3 to cm^3.

56 in^3 x (2.54cm/1in)^3 = 920 cm^3

Quiz Disappointments

Over the weekend, I reviewed the material in order to prepare for the quiz Monday. I was feeling pretty good and I feel like I had a decent understanding of what significant figures are, which was the hardest part of the unit so far for me. During the quiz, I felt like I knew what I was doing and felt like I would get an okay grade. When I checked the grade book, unfortunately, the grade was lower than I expected. At least it was a quiz and not the unit test, which is tomorrow, so the 5 points I missed should not tank my grade in the long run.

Significant Figures

The hardest lesson so far in this unit is significant figures. The definition of a significant figure is "each of the digits of a number that are used to express it to the required degree of accuracy, starting from the first nonzero digit". During the notes, I became very confused because there was a lot of information coming at once, so I did not have much time to process and understand it, but after looking at some different websites, I feel like I understand a little better. Below are some links that I feel like helped me understand what significant figures are and how to determine the number of significant figures in a number a little better.

• Websites:
• Significant Figure Rules
• Significant Figure Rules and How to do Math with Significant Figures
• Videos:
• Multiplying and Dividing with Significant Figures
• Adding and Subtracting Significant Figures

Quiz Yourself Here!

National Mole Day!

This past Friday was National Mole Day, so we had a party during class to celebrate. Since we all had a lot of room for creativity in our theme for our mole, they were all very different from each other. It was interesting to see how other people did completely different things even though we had the same instructions for our project. The connection with chemistry is that although a mole is an animal, it is also a type of measurement used in chemistry. It is expressed as 6.0221415 x 10^23. 

The history of Mole Day is explained here: Mole Day History

Unit Quiz

We took a unit quiz today. I feel like I did well and knew the material that I was being tested over, but I guess I will not know for sure until the grades are in which will hopefully be soon. I only had semi-major issues with one question, so I skipped it and came back to it. When looking at it for a while the second time around, I noticed something I had not before and easily came to the correct answer. I feel like I was successful with both the questions from this unit and the review questions from last unit.  

Beanium Lab

Yesterday, we did an activity to further our understanding on isotopes. Isotopes are atoms that belong to the same element, but the number of neutrons varies causing the atomic mass to vary between the different isotopes. This was demonstrated using different colored beans to represent the isotopes of the fictional element “beanium”. We sorted all of the beans by color and found the average mass of each individual bean for that specific color. Not surprisingly, each color had a different average mass, much like the isotopes of an element. We used these numbers and percent of abundance to find the average atomic mass of beanium. The picture shows all of our beans sorted by color. 

Atomic Theory Notes

In class, we learned about Dalton's Atomic Theory and JJ Thomson's, Rutherford's, and the current atomic model. Following are a summary of the notes for each of these model's:

• Dalton's Atomic Theory
• Elements are made of tiny particles called atoms.
• All atoms of a given element are identical.
• The atoms of a given element are different from those of any other element.
• Atoms of one element can combine with atoms of other elements to form compounds. A given compound always has the same relative numbers and types of atoms.
• Atoms are indivisible in chemical processes. That is, atoms are not created or destroyed in chemical reactions. A chemical reaction simply changes the way the atoms are grouped together.
• JJ Thomson

• Used a cathode ray tube to show that atoms of any element could be made to give off what we now know as electrons
• He concluded that every atom has these tiny, negative charged particles
• He also knew that atoms have a neutral charge, so there must be an equal amount of positively charged particles  
• Also known as "plum pudding model" or "chocolate chip cookie model"
• No nucleus

• Rutherford

• Shot high velocity alpha particles at an atom expecting there to be very little to deflect the particles
• Some particles bounced back
• Concluded that the only way they could have bounced back was if most of the atom's mass was concentrated in a nucleus
• Eventually discovered that the nucleus contained protons
  
• Current model
• Also known as the "cloud model"
• Electrons move around nucleus in a cloud
• Electron location is pinpointed using proabability





Unit 2 Pretest

While taking the pretest for this unit, I saw some things that I have vaguely remembered from past units in school, but that information was still fairly blurry in my memory. The rest of the information that was on the pretest I have never seen before. I look forward to learning a lot of new things this unit while reinstated the things I have already learned.

Atomic Inference Activity

Yesterday we did an inferencing activity that tied in with our lesson of atomic models. In our activity we picked up a covered plate that contained a marble. In the plate, there was a pattern of raised lines that the marble could not pass over. By rolling the marble around and listening to where it was rolling, we had to try and guess what the design inside was. This ties in with our lesson in that one model we learned about, the Rutherford model, was created through inferences. He shot high velocity alpha particles at an atom expecting that there would be very little to deflect the particles. Most particles acted like he expected, but some bounced back. He concluded that the only way the particles could bounce back is that if most of the mass in an atom is concentrated in a nucleus. In both our activity and Rutherford's experiment, we had to use observations of behavior to determine what was located inside something.

Nomenclature Post #2

I can apply the information I learned during the Frontier Chemistry project to the real world in that I may find myself with an ailment in the woods and have to use my knowledge of medicinal plants in order to treat myself. Much like our essay over the unit, my life my depend on my ability to properly identify plants and know their medicinal uses. These plants are actually used to treat maladies, it is not just some abstract concept only relevant to this project.

Nomenclature Post #1

What I found most difficult about this task was having to find the plants out in the wild. I found this difficult because I was not really sure what I was looking for at the time, so I felt like I was just taking pictures of random plants and hoping for the best. Also, when it came time to identifying the plants from the pictures that I took, sometimes it was difficult to see the small details that could help identify the plant. Sometimes the way the light hit the plant made it look like a slightly different color than the picture I was trying to match it with, making me concerned that I was looking at 2 different plants.

Introduction Page

Hi, I'm Macy! I am a junior and a dancer at Saint Louis Ballet School.