Tuesday, November 23, 2010

Lecture #26, Monday, November 22nd

We started the nuclear chemistry unit as it is a continuation of the alternate energy unit. France uses nuclear power for nearly 80% of their electricity, the highest in the world.

We discussed how Einstein's energy equation can be related to the amount of energy obtained in a nuclear reaction (Section 21.6) then discussed the common radioactive decay associated with nuclear reactions.

Read Sections 21.1 and 21.2 to gain a deeper understanding of the material we covered in lecture.

The Nuclear Chemistry howework will be as follows:
Chapter 21 Pages 925-926:
1-6, 11-16, 19-24, 27-30, and 33-42

Lecture #25, Friday, November 26th

Today we finished our discussion on solar cells by discussing some of the theory behind dye-sensitized solar cells or Gratzel Cells, named after their inventor, Michael Gratzel.

We then went over some helpful hints for how to construct the Gratzel cell you will be creating in lab this week.

Wednesday, November 17, 2010

Excellent Leadership Opportunity

The new Strengths-Based Coaching Program is a 10-week program that will help students connect and reflect on your complete Ohio State experience…courses, involvement, personal goals, and professional aspirations. Applications are due November 30 for the winter quarter session, and will be due late February for the spring quarter session. Please consider applying, and feel free to share with your organizations and friends who may also be interested.

Apply for the new Strengths-Based Coaching Program

Applications are available now for the new Strengths-Based Coaching Program through the Center for Student Leadership and Service at the Ohio Union. This program will serve as a vehicle for students to make meaning out of their complete Ohio State experience – personal, academic, social, and professional. Focusing on development at both an individual and group level will allow students to consider their leadership on their own terms within the context of a supportive community. Participants will utilize the StrengthsFinder assessment as part of this program. Although the program is geared towards students in their second and third years, any student is encouraged to apply!

The program will run for 10 weeks during winter quarter, and approximately 30 students will be accepted. Those students who are accepted will attend weekly meetings on Thursdays at 4:30pm from January 6-March 10, 2010.

Applications are available now at http://ohiounion.osu.edu/get_involved/csls/coaching and are due by November 30. Contact Jen Pelletier at Pelletier.17@osu.edu for more information.

Lecture #24, Wednesday, November 17th

Today's lecture was based on content from Dr. Daniel Nocera from MIT. The Nocera group studies the energy conversion in biology and chemistry. Efforts have focused on understanding the reactions of multielectron, proton-coupled transformations of energy poor substrates. From this platform, the group has successfully used solar light to split water into hydrogen and oxygen. Recently, they have realized artificial photosynthesis by the solar splitting of water under benign conditions. In doing so, the Nocera group can now provide solar energy/storage and clean water to the poor and those of the non-legacy world.

I highlighted the key points of one of his lecture and if you were interested in the material, check out his talk about "Personalized Energy." You will notice some of the slides are identical to what I used today.

Inspiration Quote:
"Success seems to be connected with action. Successful people keep moving. They make mistakes but don't quit." -Conrad Hilton

Songs Played Before Class:
Taylor Swift - Mine
Dave Matthews Band - Where Are You Going
Joe Nichols - Gimmie That Girl

Monday, November 15, 2010

Exam #2 Content

*Electrochemistry
*Thermochemistry

Read chapters 19 and 20 of the textbook and work on all the MC homework, the homework sets on Carmen, and all the old exams posted on Carmen.

The equation sheet given with the exam will be exactly the same as the first exam with the addition of the standard cell potential table.

Lecture #24, Monday, November 15th

Today we continued with photovoltaic devices and described how electrons flow through a photovoltaic consisting of silicon doped with boron and phosphorous. P-type and N-type semi-conductors were covered and how they come together to form a PN junction was also discussed (See Figure 12.12 on page 491). We also looked into how the substitution of boron and phosphorous facilitate the flow of electrons in a silicon based material and showed that only 15% of the sun's visible photons are absorbed in a silicon doped photovoltaic device.

Alternate Energy sources and fuel are also discussed on pages 195-198 of the text (note the correct of the page #'s mentioned in lecture) and the first part of this discussion is based on solar energy. Here is a link to a great web-site describing solar cells. We also highlighted the pros and cons of solar cells and indicated what the energy obtained from them depends on.

Inspirational Quote of the Day:
Take a moment to write down the following personal characteristics: confidence, poise, imagination, initiative, tolerance, humility, love, cheerfulness, faith, enthusiasm, courage, honesty, serenity.

Circle all of the characteristics you possess. I hope you circled them all because they are all within us.

Song Played Before Class:
Finger Eleven - Paralyzer

Sunday, November 14, 2010

Quiz #7

As mentioned in class, "Quiz" #7 is a Mastering Chemistry homework assignment and is currently available. Please be sure to set aside a decent portion of time to complete this assignment as it is not a short one and you are allowed 3 attempts to complete it.

Friday, November 12, 2010

Lecture #23, Friday, November 12th

The main objective in today's lecture was to compare and contrast the differences we observe between a molecule and a solid. In molecules we have isolated units giving rise to discreet energy levels we observe in a molecular orbital diagram. In a solid the infinite number of atoms present leads to bands of molecule orbitals, which are wider in energy than the molecular orbitals in molecules.

Many of the physical properties of solids are dictated by the energy gap of the highest energy band containing electrons, which is referred to as the valence band, and the lowest energy band that does not contain electrons, or the conduction band.

The magnitude of the difference in energy between these two bands is referred to the band gap. Band gaps are typically reported in units of electron Volts (eV), so be sure to know how to convert from eV to Joules and vice versa.

At the end of class I briefly discussed photovoltaic devices and what chemists can do to manipulate the band gap and design better materials with more desirable properties. We will pick up with that discussion on Monday. If you want to get a better glimpse of photovoltaic devices and solar cells, here is a neat link.

Inspirational Quote of the Day:
"The time to prepare isn’t after you have been given the opportunity. It’s long before that opportunity arises. Once the opportunity arises, it’s too late to prepare."

Song Played Before Class:
Rascal Flatts - Here's To You

Thursday, November 11, 2010

Lecture #22, Wednesday, November 10th

Today we started the last unit of the quarter, which will cover alternate energy. This topic has gained considerable interest in both the scientific and political communities and is a nice topic to end on as we can combine several topics throughout all of general chemistry to better understand the principles behind alternate energy.

The first look at alternate energy comes in chapter 12 of the text titled modern materials. Many of the technologically relevant materials our society craves come from materials. While it is nice to study the ideal gas laws and properties of solutions, it is materials research that will allow us to argue whether the iPhone 4 is better than the HTC Evo.

Next week in lab you will begin constructing your own solar cell. The idea for this laboratory experiment came from the following youtube video, which you will need to watch in order to complete your pre-lab assignment. Solar Cells are contained in Chapter 12 of the text and we will include it in our alternate energy unit.

Before we dive into the content in Chapter 12, it is relevant to review the material from the transition metal chapter regarding molecular orbital diagrams. The properties of materials are highly dependent upon the energy difference between the energy levels of the molecular obitals containing electrons and the molecular orbitals that are empty.

In molecules this is called the HOMO-LUMO gap and in materials we refer to this energy difference as the band gap. To manipulate these orbital energies changing the transition metal center or the ligand.

We also reviewed the molecular orbital diagram of a hypothetical octahedral complex with titanium at its center containing six oxygen ligands. Next lecture we will see how these orbital energies change as we go from a discrete molecule to an extended solid.

Songs Played Before Class:
Jay Z feat. Rihanna and Kanye West: Run This Town
Michael Jackson-The Way You Make Me Feel

Monday, November 8, 2010

Lectures #20-21: Friday, November 5th & Monday, November 8th

Section 20.9 of the text is titled Electrolysis and we discussed how to relate the electrical charge and quantity of electrolysis. These calculations map up with what was performed on the 2nd day of the Electrochemistry lab.

Section 20.8 was the next part of the lecture discussion covering batteries and fuel cells. You will be responsible for all the lecture material including: Lead-Acid Batteries, Alkaline Batteries, Nickel-Cadmium, Nickel-Metal-Hydride, Lithium-Ion Batteries, and Hydrogen Fuel Cells. Be sure to look over your notes and read Section 20.8

The last section in the electrochemistry unit is Corrosion. Up to this point we discussed various ways to make a spontaneous process even more spontaneous. With corrosion we essentially want to take a process that is spontaneous and try to stop it from happening. Such is the case in the corrosion of iron or the rusting of iron. By utilizing what we know about electrochemical reactions, we can predict which species can prevent the formation of rust.

The 2nd exam will cover content from the Thermochemistry and Electrochemistry units. The content in these two units is vital for many disciplines and many majors require you to take Chem 123 for this content. Be sure to through the homework problems and practice problems in Mastering Chemistry in order to not only obtain the correct answers to these problems, but to know the reasons why we arrive at the correct answers. Right now is the time to start studying for the upcoming exam (actually, you should have already started). I ran across this video clip from the movie "Any Given Sunday," where Al Pacino plays Tony D'Amato, a head football coach of the Miami Sharks. He gives the following motivational speech to his team before their final game. In this speech he discusses the margin of error between winning and losing:

“You find out that life is this game of inches! So’s football. Because the margin for error in either game, football or life, is so small … so small, guys. One half-step too late or too early and you don’t quite make it. One half-second too slow or too fast and you don’t quite catch it ‘cause it’s half a fingertip away. The inches we need are everywhere around us, they’re in every break of the game, every minute, every second.
… On this team we fight for that inch! We tear ourselves and everyone else around us to pieces for that inch! We claw with our fingernails for that inch ‘cause that’s what makes the ******* difference between winning and losing – between living and dying.”

This is the battle that most students face in general chemistry. The topics we discuss in Chem 121 and Chem 122 start adding up inch by inch to come together to tell a fascinating story. In order to understand the material in this class you need to be able to fight for that inch. A line from the speech says "I can't make you do it." I can't make you open your book or complete your homework assignments, but that is what is going to separate the students who succeed in this course from the ones who do not. Those who are willing to fight and claw for that inch. This is true for this course and will be true when you graduate and find yourself in the workforce.

It's hard to imagine that we are actually in week #8 of the quarter. As everything begins to wind down, I've looked for an idea for a project that will tie many of the concepts learned in general chemistry together. I finally came up with the Solar Cell project as it ties in with Chapter 12 of the text and the transition metal and electrochemistry units in the text. Chapter 12 is titled "Modern Materials" and it touches on many new technologies that are shaping the way we function in our everyday lives. This content will lead us to understand the principles behind the solar cells you will construct in the lab.

Inspiration Quotes:
“A gem cannot be polished without friction, nor man perfected without trials.”
-Chinese Proverb

“Concern for man and his fate must form the chief interest of all technical endeavors… Never forget that in the midst of your diagrams and equations.”
-Albert Einstein

Songs Played Before Class:
Jay-Z - History
Kenny Chesney - We Went Out Last Night
Cali Swag District-Teach Me How To Dougie
Montgomery Gentry - Something To Be Proud Of

Wednesday, November 3, 2010

Quiz #6 Material

Quiz #6 will cover sections 20.1-20.6 and 20.9 from the textbook. To better prepare you for the quiz you should complete the Electrochemistry homework set that is posted up on Carmen.

The quiz will take place Mon./Tues. during the first 20 minutes of lab.

Excellent Tutorial Web-Site

I found an excellent tutorial site the other day, which can be found here and it should send you to the link on entropy. It is a great guide and gives useful summaries on topics you may have forgotten from earlier chapters. If you ever find any on-line material useful please let me know as I can take a look at it and if it is useful I can share it with the rest of the class.

Time to get this blog updated!

Wow, there has been a great deal of material covered since the last blog. So let me catch you up on the Thermochemsitry material.

After a brief introduction of thermodynamics, I discussed what thermodynamics can and can't tell us about a reaction mechanism, and then introduced entropy. We discussed the second law of thermodynamics and I gave some guidelines for the entropy of the universe. We can also associate numerical values with entropy and the third law of thermodynamics allows us to do so by defining the entropy of a pure crystal at 0 K. I also performed an example very similar to what we saw in chapter 5, where we had to calculate the standard entropy of a reaction, which is the exact same method used to calculate the standard enthalpy of a reaction.

In the last 5 minutes I put the Gibbs Free Energy equation on the board because you will need it in lab this week.

The last section of the Thermochemistry lecture's focused mainly on Gibbs Free Energy, which is sections 19.5, 19.6, and 19.7 of the textbook. I would read all three of these sections of the text, and after reading those sections, you should have no problem in completing all of the Thermodynamics homework set.

I began the next class by discussing some issues we had in the lab in calculating Ksp. One main idea that I want to emphasize to everyone in this class is to "Think like a chemist." Don't simply go through the motions and calculate numbers in the lab. These numbers have meaning and I want you to see the underlying meaning behind them. Chemistry can be so frustrating because students rarely appreciate where the numbers and formulas come from. I want you to see how everything relates together. The solubility chapter overlaps so much with the Thermochem chapter and has many applications in the transition metal unit.

The numerical results of the Thermodynamics lab were discussed. I gave a powerpoint presentation, which is posted on Carmen. Remember that chemistry is an experimental science and all the theories and equations were developed from experimental data. Today we discussed why the value we obtained for the entropy change for a process in which a slightly soluble salt dissolved was negative. We also analyzed why the same reaction had a negative enthalpy change.

We finished the Thermochem unit by discussing the "Chelate Effect," which takes experimental values obtained in the synthesis of transition metal complexes and relates them to the overall entropy of a particular reaction. This effect is seen in cases where polydentate ligands replace monodentate ligands in transition metal complexes. The "A Closer Look" box on pages 1021-1022 describes this theory into more detail.

The next unit we will discuss is electrochemistry. Electrochemists study and try to manipulate the flow of electrons. This is seen in almost every practical material involving electricity. The main principle I want everyone to keep in the back of their minds is: How can a chemist manipulate the flow of electrons. Once we understand this concept we can then go on to bigger and better problems such as assembling a battery or electrochemical cell to power anything from an electronic device to an automobile.

The electrochemistry lectures focussed on the principles related to the lab and Chapter 20 of the textbook. Thus far, we have covered the content from Sections 20.1 - 20.6 in the textbook. I will finish up this unit soon with section 20.9, which is titled electrolysis and this is the content of the second electrochemistry lab period.

For the time being we will skip over section 20.7, which is batteries and fuel cells, but in our energy unit we will come back to it. The next unit will focus on energy and many of the electrochemical principles will resurface.