Chem 1111 - Robertson

Moderator: Ron Robertson

Re: Chem 1111 - Robertson

Postby Ron Robertson » Wed Apr 08, 2015 10:39 am

Finally finished the Molar Mass of Butane lab reports !

The distribution of grades was 7 A, 5 B, 8 C, 7 D, and 2 F. Three people still registered for the course did not submit reports and have received zero marks. Many of the reports were pretty good. As you progress in the sciences you will be writing many of these and your instructors will have slightly different expectations. You will have to adjust to what each of us wants in the different sections. I don't remember anyone consulting with me before the turn-in deadline. I think that would have helped with several of you.

General comments

Introduction - This is the hardest section for most to write. A good outline for this lab would be to talk about butane and its uses first, then move on to how butane gas can be collected, and then to finding the molar mass using the ideal gas law equation and Dalton's law of partial pressures. End with the purpose.

Procedure - Several people did not write in past tense of passive voice. This is the style I requested. Most people wrote this section fairly well but some left out necessary details.

Results/Data - There were small sf and unit problems in the data table itself. Most of the deductions came from the sample calculations section. A few people totally missed the point of the lab and used the true value of the molar mass of butane to get the moles of butane. This was a major error of course. The organization of the sample calculations really makes a difference in understanding the report. I have copied some of the better reports so you can stop by and see how some others organized this section.

Conclusions/Discussion - This is another tough section but I have tried to make it easier by requesting 3 major paragraphs with 3 different ideas. Paragraph one should answer the purpose and this should be backed up with data. Paragraph two should discuss errors - design and the variation of the trials (precision). Numerous people used the terms precision and accuracy incorrectly in talking about your errors. Many did not talk about the variation of the molar mass numbers from trial to trial at all. I really believe that one of the major design errors (unless you made a mistake of course) is the reading of the volume. It is tough to get very many sf when you are trying to lower you head close to the water to get a decent reading of the graduated cylinder. Paragraph three should discuss the significance or application of the experiment itself or the number you obtained for the molar mass.

References - You should always reference the lab handout itself. That is where you got the procedure. Also make sure you look at the web reference I gave you for different referencing styles. The date of access should be shown. Page numbers are needed for a book reference. Most importantly - all references must be cited in the paper.

There is a wide variation in the writing ability of students in the class. I have tried to point out weaknesses in my comments. Some are a little "wordy" while others definitely need to add more "meat". Some have a nice sense of flow of the material while the writing of others is very choppy. This is where letting someone else read the paper really helps.

Finally, I have looked at the originality scores on turnitin.com as well as your submission dates. Three people received a 2 pt deduction for a late submission to turnitin.com. (This is separate from the paper submission late turnin) One person received a 2 point deduction for a high (poor) originality score. I would expect scores in the 20 - 30 % range on this lab since I told you to use the same data table as in the lab report and the procedure section should be pretty similar. I have looked specifically at the intro and discussion sections to see if large blocks have been copied. The program is really amazing. Many of your papers here at APSU will be submitted online like this. It does help to hold students' accountable for the use of material from various sources.

Your paper reports are in the box and ready for pick-up. Please come by and we can discuss your lab report. Thanks for your hard work on this!
Ron Robertson
 
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Re: Chem 1111 - Robertson

Postby Ron Robertson » Fri Apr 10, 2015 12:44 pm

The Beer's Law lab sheets are graded and ready for pick-up. Grades were good.

Post lab question #3 was the only problem. The color of a solution is determined by the wavelength of light which is not absorbed by the solution. Many of you answered a different question - "How does the intensity of the color in a solution relate to the number of solute molecules?" The answer to this is that the intensity of the color is determined by how much solute there is in solution. This is Beer's Law.
Ron Robertson
 
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Re: Chem 1111 - Robertson

Postby Ron Robertson » Mon Apr 13, 2015 9:44 am

The Heat of Neutralization quizzes are graded and in the box for pickup. A key is on the board. Come on by and let's talk about what you missed.
Ron Robertson
 
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Re: Chem 1111 - Robertson

Postby Ron Robertson » Mon Apr 13, 2015 10:01 am

Probably the last extra credit opportunity is this Friday at the university Research forum in the ballroom at the MUC. Extra credit can be earned by evaluating 5 projects similar to the MTSEF assignment. The posters should be up from 1 - 4:30 pm. You will evaluate 5 different projects for a max of 10 pts. The evaluation sheet can be found at http://apbrwww5.apsu.edu/robertsonr/nova/xtracredit.pdf. See the announcement flyers around the chem department for more details. There are oral presentations as well as the posters.
Ron Robertson
 
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Re: Chem 1111 - Robertson

Postby Ron Robertson » Tue Apr 14, 2015 9:41 am

The "Copper" lab is interesting today but long and I will try to get us into the lab quickly. It does make setting a due date very difficult. It is possible that some of you will not get completed with the lab and may have to store your solution, waiting until next week to weigh your copper. You must get through step 18 in the lab today though. I really believe most of you will finish.

What I am going to do is to ask that you submit the data sheet p. 5 of 7 and post lab question #1-3 (on p. 6 of 7) by 5 pm Wednesday. If you are not finished, leave that section blank on the data sheet as well as question #3 on the post lab. I will return your data sheets partially graded and you will complete them next week and return them to me by the end of lab. If you get completely through today then please complete all the questions and you will receive a finished grade.

Our experiment next week (the last one of the semester) has changed. Instead of the non-experimental "Molecular Modeling" we are going back and doing the missed "Empirical Formula of a Compound" lab. This lab will not be a full report however.
Ron Robertson
 
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Re: Chem 1111 - Robertson

Postby Ron Robertson » Thu Apr 16, 2015 3:24 pm

I have your labs graded and they are in the box for pick-up.

The lab report was very simple and there were lots of excellent grades. The major weakness was the question about how the experiment showed the conservation of mass. I felt you should have included the major ideas that are found in the statement below -

"The law of conservation of matter states that matter is neither created or destroyed in a chemical change. Since the elemental copper used is merely changed into other substances by a series of chemical changes and is regenerated at the end, the mass of copper initially used should equal the mass of copper recovered at the end."
Ron Robertson
 
Posts: 413
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Re: Chem 1111 - Robertson

Postby Ron Robertson » Mon Apr 20, 2015 10:08 am

I am waiting for a couple of folks to come by and take their quiz from last week that they missed. I have notified them and they have until 1:30 pm. I will put your quizzes out at 2 pm for pick-up. A key will be on the board.
Ron Robertson
 
Posts: 413
Joined: Fri Mar 12, 2010 10:49 am

Re: Chem 1111 - Robertson

Postby Ron Robertson » Tue Apr 21, 2015 9:23 am

Our last lab today - an oldie but goodie for sure!

Long ago in a classroom far away you studied about empirical formulas and how we can use the mole concept and the elemental breakdown of a compound to determine the simplest ratio of the atoms in a molecule (or formula unit) of that compound. In this lab we make a compound and have the ability to know what the masses of each element are and that also gives us the ability to find the empirical formula. Now that you are experts in the use of the "mole" and "stoichiometry" you can also flex some higher order reasoning skills on my revised post lab. Enjoy!

Due on Wednesday at 5 pm

Data sheet page 3 of 7
A revised calculations page that also replaces page 4 of 7
A revised post lab page
Ron Robertson
 
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Re: Chem 1111 - Robertson

Postby Ron Robertson » Wed Apr 22, 2015 9:39 am

The Copper Cycle quiz is graded and ready for pick-up. A key is posted. Come by and let's learn how to determine ox # and whether a reaction is redox or not. This is a good review for this material on your Chem I final. This will be covered in even more depth in Chem II. You gotta learn those ox # and be able to use them to determine ox states in polyatomic ions as well as compounds . . . .and free elements have zero ox #.

Top lab of the semester - Molar Mass of Butane (9), Copper Cycle (8), Aspirin (7)
Least - Penny lab (9), Measurement (5)
Ron Robertson
 
Posts: 413
Joined: Fri Mar 12, 2010 10:49 am

Re: Chem 1111 - Robertson

Postby Ron Robertson » Mon Apr 27, 2015 11:26 am

The remaining Cu Cycle labs and the Empirical Formula labs are graded and in the pick-up box. I believe this completes all regular lab material for the semester. I will be working on your extra credit the next few days and you will hear from me again when I have your grades completed.
Ron Robertson
 
Posts: 413
Joined: Fri Mar 12, 2010 10:49 am

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