Unit Exam

Today, we took the unit test for stoichiometry. I think that I did better than I anticipated, but it was definitely easy to make mistakes. Especially since there was two times that 2 or 3 questions went with one reaction/equation, so if the first question was messed up, then so were the rest. I felt like I had an easier time on the test than the quiz, but I'm just really anxious to get my score back.

One thing I hate to admit, but I struggled on remembering polyatomics... Specifically chlorate. I ended up getting it, but it definitely took me some time to remember. Also, I think the hardest thing for me with this unit was simply the way that the questions were worded. I know how to do stoichiometry pretty well, but when different types of information is given in a question with different formats, I get confused.

All in all, I enjoyed this unit. Unlike the rest, it was a basic background that simply needed to be applied in different ways, whereas other units had a lot of different concepts to apply.

Here is a video that reviews stoich:
http://www.chemteam.info/Equations/SingleReplacement.html

And this is a source that also reviews, but provides a broad array of information with review problems as well: http://www.chemteam.info/Stoichiometry/Stoichiometry.html

Day 2 and 3 of Copper (II) Chloride Lab

We have completed the lab. On day 2, we simply took the nail out of the copper (II) chloride solution and used hydrochloric acid and distilled water to wash the copper, and then left it to dry over the weekend. On day 3, we weighed the nail and the jar with the solid copper. For mine and Bri's lab, we found out that we produced a 3+ ion of iron.

Below are pictures of day 2:


And day 3:



Below is a link that explains single replacement reactions:
http://www.chemteam.info/Equations/SingleReplacement.html

Percent Yield

Percent yield is probably the easiest part of stoichiometry. After calculating the theoretical yield (what should be produced) and knowing the actual yield (what was actually produced), you simply plug these two numbers into a formula to find out the percent of the theoretical yield that was yielded from the experiment. This comes after all the hard stuff, which is the actual stoich that is being calculated.



This are two videos that go through this concept:
http://study.com/academy/lesson/how-to-calculate-percent-yield-definition-formula-example.html
https://www.youtube.com/watch?v=LicEaaXhlEY

Copper (II) Chloride Lab

Today in class, we did the first day of the Copper (II) Chloride Lab. This simply consisted of preparing the nail in the solution to be decomposed. We measured the jar and copper (II) chloride, and we then combined this with water in the jar. After mixing it so the crystals dissolved, the appearance was a bold blue liquid. We placed the nail in the solution, and now we simply wait for the copper (II) chloride to react with it.

Here are some pictures of the lab:


Also, below is a source that synthesizes chemical reactions and stoichiometry:
https://www.khanacademy.org/science/chemistry/chemical-reactions-stoichiome

Oxidation Rules

1. pure elements (stand alone elements) have an oxidation number of zero
2. for monoatomic ions (metal elements), the oxidation number is equal to its charge
3. fluorine alway has an oxidation number of -1 when in compounds
4. Cl, Br, and I always have an oxidation number of -1 in compounds, except when combined with oxygen or fluorine
5. the oxidation number of H is +1 and of O is -2 in most compounds.
• exceptions for H: in compounds with metals, H is -1
• exceptions for O: in peroxides, the charge is -1
6. 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 to the charge of the ion

Here are a couple references that help explain:

http://www.dummies.com/how-to/content/rules-for-assigning-oxidation-numbers-to-elements.html

http://www.wikihow.com/Find-Oxidation-Numbers

element	usual oxidation state	exceptions
Group 1 metals	always +1
Group 2 metals	always +2
Oxygen	usually -2	except in peroxides and F2O (see below)
Hydrogen	usually +1	except in metal hydrides where it is -1 (see below)
Fluorine	always -1
Chlorine	usually -1	except in compounds with O or F (see below)

Metals Lab

Today, we did a lab testing the reactivity of some metals with different solutions, such as water and HCl. It was interesting to see reactions of metals first-hand and how different things reacted. For example, some bubbled and fizzed, some smoked, and some simply changed colors. All in all, we had to mak our own reactivity series depending on the results, and this helped me better understand this concept by making my own and just witnessing it myself. Below is a picture of some of the reactions!

Here is an example of a reactivity series. As shown, the elements towards the top are the mots reactive with most things, and vice versa.

Also, here is a link that explains reactivity series: http://www.bbc.co.uk/education/guides/zqjsgk7/revision

Redox Reactions

Redox Single Replacement:

• element + compound > element + compound
• driving force = transfer of electrons
• the metals change places
• "like attacks like" = metals attack metals, nonmetals attack nonmetals

Synthesis Redox:

• 2 or more reactants form one product 
• A + B > AB

Decomposition Redox:

• 1 reactant produces 2 or more products
• AB > A + B

Combustion Redox:

• when a hydrocarbon reacts with oxygen (O2), the product are ALWAYS H2O and CO2
• oxygen is always a reactant

Here are two videos on redox reactions:

https://www.youtube.com/watch?v=lQ6FBA1HM3s&feature=youtu.be&list=PL8dPuuaLjXtPHzzYuWy6fYEaX9mQQ8oGr

https://www.khanacademy.org/science/chemistry/oxidation-reduction/redox-oxidation-reduction/v/oxidizing-and-reducing-agents-1

Solubility Rules

Solubility rules have been hard for me to memorize. I still struggle with remembering some of the exceptions, but this video helped me a lot:
https://www.youtube.com/watch?v=AsCLuLS-yZY

There are a lot of little things to remember that will cause you trouble if you don't catch them. So here is an in-depth explanation:
http://www.chem.sc.edu/faculty/morgan/resources/solubility/

First Lesson

Chemical reactions sometimes get confused with physical changes. Some sensory details to know if something is a chemical reaction are...

• color change
• solid forms
• bubbles form
• heat/flame is produced or heat is absorbed
• ΔH is the sign to show temperature change, also called "enthalpy"

Below is the anatomy of a chemical reaction:

***don't forget about HOFBrINCl's!!!!

Here is a helpful video as well:

https://www.youtube.com/watch?v=AKiAjW7xHOc

Diatomic Elements

A small trick that many forget during this unit is diatomic elements. There are 7 of these that when they stand alone, their mass from the periodic table must be doubled. When they are a part of a compound, their mass from the table stays the same, though. This was one of the questions I missed on the quiz that I need to pay attention to on the unit test tomorrow.

Here is a link that explains it. In class, we learned the trick "HOFBrINCl" to remember the seven elements. This link says to think of "Have No Fear Of Ice Cold Beer", a less appropriate, but a more funny way to remember that may stick in brains better :)
http://chemistry.about.com/od/elementfacts/f/What-Are-The-Seven-Diatomic-Elements.htm

Empirical Formulas

Another part of this unit is empirical formulas. They differ from molecular compounds in that they are the lowest number ratio of elements in a compound that cannot be reduced. Molecular formulas would look something like C10H22 whereas empirical would look like C5H11. They can be the same if the molecular is reduced, though.



http://www.chemteam.info/Mole/EmpiricalFormula.html

Mole Conversion

Throughout this unit, we have become used to using this method of converting because it is the way to find all of the calculations for this topic. A lot of times, it is pretty straight forward, but other times it gets confusing. For example, there were a few questions on the weekly quiz that caused me trouble because they weren't as straight forward as the road map entails. I'm going to look over these types tonight to review for the test tomorrow which will probably have a lot.

Here is a link to the road map!

http://www.orschemistry.com/orspvchem1112/ChemHonors_files/moleroadmap.pdf

Formula of a Chloride Lab

Yesterday, we did the second lab for this unit, which is the formula of a chloride lab. We combined zinc and chlorine to form a zinc chloride compound. This happened by heating the zinc and chloride, evaporating the excess HCl in the liquid.


 
 

Formula of a Hydrate Lab

Today, we did the formula of a hydrate lab. I thought it was very interesting to get to take out the water from the CuSO4 ourselves with the Bunsen burner. I also thought it helped put the math part into better perspective because we got to experience it and come up with the data ourselves, so it helped me understand more.
Here are a couple pictures of mine and Bri's lab :)



Also, here are a couple references:
http://www.occc.edu/kmbailey/chem1115tutorials/Stoichiometry_Molar_Mass.htm
https://www.youtube.com/watch?v=xPdqEX_WMjo

Chemical Composition Pre-Test

We just took the pre test for this unit, which is chemical composition. Personally, although no one really knows what they're doing on pre tests, I think this was the hardest one. It seems like there is going to be a lot to remember and keep track of with a lot of intricate math that could get really confusing. It could be just me, but I think this unit is going to be tough.

Here's a couple videos that may help in the future!
https://m.youtube.com/watch?v=QcC4OsSxWYU
https://m.youtube.com/watch?v=Pft2CASl0M0

Also, here are two examples of chemical composition that are relevant to our lives:

Last Meal Project

Our project for this unit is called the Last Meal Project. Essentially, we are supposed to chose the appetizer, main course, and dessert that we would like to have for our last meal. I chose buffalo chicken dip, chicken and potatoes casserole, and cheesecake brownies. On my page for this project, you can see all of my conversions to metric units!

Here is the link that I found most helpful for converting: http://www.jsward.com/cooking/conversion.shtml

Also, here is an example of what my conversions looked like: 

Dimensional Analysis

Yesterday, we learned about dimensional analysis, and this was basically a review of what I have learned in math classes. Dimensional analysis is basically a way to convert one quantity to another quantity with a different unit of measurement. Some fun facts are that significant figures are infinite when the number is an exact quantity (1 in = 2.54 cm). The way to end up with the correct desired unit and have the starting unit cancelled out is to put the starting unit measurement in the denominator so it cancels and put desired unit in numerator so the ending calculation contains this. It may take a series of multiplication steps, but the same rule will be followed.

Here is a couple links to help with dimensional analysis:
http://www.chem.tamu.edu/class/fyp/mathrev/mr-da.html
http://www.alysion.org/dimensional/fun.htm

Significant Figures & Conversions

Today we learned about lots of things, including all about significant figures and the units of measurement in the metric system. I think it's pretty straight forward, but a lot of it is contradicting to things like rounding rules that we've been used to.

Below is a video that I found very helpful when I was kind of confused:
https://www.youtube.com/watch?v=6oj4y0d44nQ

Also, here are a couple pictures of the notes from today!

Pre-Test Thoughts

Today, we took our pre test over the measurement unit. I have mixed feelings about it because although I thought it made no sense today, I think that once we learn this material, it might come pretty easily. It isn't a hard concept because it is pretty straight forward, but it will definitely take some learning to become comfortable with things such as converting.
Below is a picture and a link that may be helpful in the future for this unit!



http://www.metric-conversions.org/metric-conversion-table.htm

Aspirin Lab

Today, we finished our second day of the lab and are now going to leave the crystals to dry over fall break. It was really cool to come in this morning and see the transition from just liquid to actual crystals.

We utilized measurement by using a scale to weigh parts of our experiment such as the starting material, the watch glass, and the filter paper. We will be recording the dried material once we come back.

Here is a reference to the experiment itself! http://www.chem.latech.edu/~deddy/chem104/104Aspirin.htm

And, below are pictures of our measurements and the aspirin so far:

 

Post Star Project

Today is the due date for our star project, and I'm really proud of mine. I finished several days early, and I think it has good content as well as organization and appearance. At first, I struggled with finding some of the chemicals in the stars, and since I started early, no one had shared helpful links yet so I was kinda left on my own. I eventually figured it out though, but it would have definitely been helpful to have those links ahead of time. All in all, I found it super interesting to actually look at our stars in depth. Not only did I not know much if anything about stars, I had no idea a majority of them even existed. So it was really cool to be able to see what is actually out there!

Here are a couple of links I used for my project:
http://www.universetoday.com/45775/famous-stars/
http://stars.chromeexperiments.com/

Forensic Archaeology Lab

In class today, we began the archaeology lab to research half life. All we got to do today was cut out the 567 squares that represented atoms of the radioactive remains taken from the skeleton that was found by deer hunters. In a quiet town in South Carolina, they stumbled across the skeletal remains and are teaming with archaeologists to found out the mystery. All in all, we are researching the rate at which the body decayed to see the approximate time she was killed. Here is a picture of the 567 squares we cut out!

Beanium Lab

In class today, we conducted a lab with a made up atom called Beanium. We had 4 different isotopes (red, black, white, pinto). The number of atoms in each isotope, total mass of the isotopes, average mass of the isotope, and the percent abundance were all found.

Here is our data table:

Isotope	# of atoms of this isotope present	Total mass of all the atoms of this isotope	Avg. mass of this isotope	% abundance of this isotope
White beanium	79	23.33 amu	.295 amu	40.9%
Black beanium	60	11.88 amu	.198 amu	31.3%
Red beanium	39	13.85 amu	.355 amu	20.2%
Pinto beanium	15	5.17 amu	.345 amu	7.78%

And here is a picture of Kendall doing the lab and sorting out the different "isotopes" :)
Here is a helpful link if you're lost on how to calculate all this: http://www.chemteam.info/Mole/AvgAtomicWt-Reverse.html

Info on the Subatomic Particles

The three subatomic particles in an atom are protons, neutrons, and electrons.

Relative masses:

• proton = 1 amu
• neutron = 1 amu
• electron = 1/1840 amu

Protons give an element its identity and mass

Electrons give an element its reactivity

Neutrons give an element its isotope

A helpful website that breaks this down further is http://chemwiki.ucdavis.edu/Physical_Chemistry/Atomic_Theory/The_Atom/Sub-Atomic_Particles 

Law of Constant Composition

The Law of Constant Composition merely states that all compounds of the same species are always made of the same things and therefore yield the same percent composition/proportion by mass. This basically means that in any single compound containing the same elements, the percentage of composition for each element is the exact same in all of these compounds.

A video that illustrates this fact is found here: http://www.youtube.com/watch?v=2nAYSy8N_x0.

Current Atomic Model

The current model of an atom has been long researched and has taken several contributing scientists and their research. These scientists include Thompson, his student Rutherford, and Dalton's theory of course.

JJ Thompson discovered that something had a negative charge in atoms contained in positively charged matter which were later found to be the electrons. His model is often described as "the cookie model" because what he envisioned resembled a cookie.


Rutherford was Thompson's student who continued his research of atomic structure. He further proved the presence of a positive charge in the center of an atom, which are the protons that are contained in the center structure called the nucleus.


These two major findings contributed to the current atomic model, which is called the cloud model.


A helpful website to understand the current atomic model and its complete evolution is at http://www.projectsharetexas.org/sites/default/files/resources/documents/EvolutionOfAtomicMode.l.pdf

Dalton's Atomic Theory

The first thing we learned in this unit is Dalton's Atomic Theory. He was the first scientist to look into atoms, and he did not know anything of the structure (electrons, protons, nucleus, etc). Although this is true, he constructed 5 theories about atoms that mostly still hold true today--besides one.

1. all elements are composed of atoms
2. atoms of a given element are identical (this is the one that was later found to be false)
3. atoms of different elements are different
4. compounds contain atoms of different elements
5. atoms are indivisible and aren't created or destroyed in chemical reactions (partially true)

A website that elaborates on Dalton's theory is http://dl.clackamas.edu/ch104-04/dalton's.htm.

Entry #2 Nomenclature- Naming Acids

Another method of naming in Nomenclature is naming acids. There are a few obstacles to remember, and again, this diagram helps visually sort that out.

*NO O = HYDRO*
*-ITE = -OUS*
*-ATE = -IC*

Entry #1 Nomenclature- Naming Type 1, 2, & 3

Below is a diagram that I found useful from our textbook to organize the ways of naming binary compounds. This is helpful for all of the visual learners that like flowcharts and diagrams to organize things in their head!

Introduction Page

Hi, I'm Avery! I'm a junior and this is my Pre AP Chemistry blog! I'm a part of several clubs in school including NHS, Student Council, FBLA, DECA, HOSA, Chem Club, and FCA. I also play soccer, for my club and for school. In the future, I would like to go into the medical field and possibly specialize in either neurology, cardiology, or trauma. I also love to spend time with friends and family :)