Today we continued looking at redox reaction and oxidation numbers, and we talked about hints to classify rxn types. We moved into Chapter 5 and looked at the "simple" gas laws (Avogadro's, Boyle's, Charles') and the Ideal Gas Law in both linear and comparative forms. On Wednesday we will continue working with gas laws and other things related to gases.
There is a new Mastering Chemistry assignment posted. When I checked this morning, I believe only 10-12 people had even attempted the MC assignment that is due tonight. If you leave these assignments until the last minute, it's very difficult for me to help if problems pop up.
2008/09/29
2008/09/26
Solutions, stoichiometry and reaction types
Today we went through a solutions/stoichiometry problem and talked about gas-forming and redox reactions. We will spend a few more minutes on redox reactions on Monday before moving on to Chapter 5.
There's a new MC assignment posted. That means that right now there are 3 active MC assignments, one due tonight, one due Monday, and one due Tuesday. I'll remind you all once again, don't wait until the last minute to look at Mastering Chemistry assignments. Also, as we did in class today, I am happy to work through extra examples similar to the MC problems you might be struggling with, just let me know. The easiest way to do this is to send me an email, but you can also print off the problem you're stuck on and show me in class.
Have a good weekend.
There's a new MC assignment posted. That means that right now there are 3 active MC assignments, one due tonight, one due Monday, and one due Tuesday. I'll remind you all once again, don't wait until the last minute to look at Mastering Chemistry assignments. Also, as we did in class today, I am happy to work through extra examples similar to the MC problems you might be struggling with, just let me know. The easiest way to do this is to send me an email, but you can also print off the problem you're stuck on and show me in class.
Have a good weekend.
2008/09/24
Acid-Base reactions
Today we continued talking about types of reactions and why reactions happened. We started talking about "molecule-forming reactions", starting with acid-base reactions.
There's a new MC assignment posted, don't leave these until the last minute. The last time I check there were only 10-15 people who had started the MC assignment that's due on Friday.
There's a new MC assignment posted, don't leave these until the last minute. The last time I check there were only 10-15 people who had started the MC assignment that's due on Friday.
2008/09/22
Chem 150 Calendar
I've set up a Google Calendar for class, it's in the list of "Useful links" to the left. I'll do my best to keep it up to date with MC assignments, etc. If you have anything you feel should be included on the Chem 150 calendar, please let me know. I've already put the SI sessions on, although some of those may be moved/cancelled around exam times.
Solutions and precipitation reactions
We touched on a few topics today:
1. Reviewed solutions and molarity
2. Dilution calculations, if you can remember how to use C1V1=C2V2, you will rock dilutions
3. We began to discuss why reactions occur. The first reaction type we looked at is precipitation metathesis reactions. If two (or more) aqueous solutions of ionic solutes are combined and a precipitate can form, the reaction will occur to generate that precipitate. We need to look at solubility rules to predict whether or not a combination will form a precipitate. Solubility rules are summarized in your textbook, Table 4.1 on page 154.
4. We talked about the importance of net ionic reactions in understanding the chemistry that occurs in a reaction. Net ionic equations describe chemistry. One more time, if you just want to explore the chemistry of a reaction, the net ionic equation will give you the best picture. Full molecular/formula equations are important to understand what's being combined (macroscale), but net ionic equations describe the chemistry. For example, if I want to make some silver(I) carbonate solid, I can go into the stockroom and grab a bottle of silver(I) nitrate and a bottle of potassium carbonate, dissolve some of each in water, and combine the solutions to make a silver(I) carbonate precipitate as described by the following equation:
2 AgNO3(aq) + K2CO3(aq) --> Ag2CO3(s) + 2 KNO3(aq)
If I really want to describe the chemistry of this reaction, the potassium and nitrate ions aren't really doing anything. The only reason they're there is because I need to balance the charge of the silver(I) and carbonate ions in the solid reagents I get from the shelf. To describe the chemistry, I can (and probably should) use the net ionic equation:
2 Ag+(aq) + CO32-(aq) --> Ag2CO3(s)
Don't forget the old MC assignment (due tonight) and the new MC assignment (due Friday).
1. Reviewed solutions and molarity
2. Dilution calculations, if you can remember how to use C1V1=C2V2, you will rock dilutions
3. We began to discuss why reactions occur. The first reaction type we looked at is precipitation metathesis reactions. If two (or more) aqueous solutions of ionic solutes are combined and a precipitate can form, the reaction will occur to generate that precipitate. We need to look at solubility rules to predict whether or not a combination will form a precipitate. Solubility rules are summarized in your textbook, Table 4.1 on page 154.
4. We talked about the importance of net ionic reactions in understanding the chemistry that occurs in a reaction. Net ionic equations describe chemistry. One more time, if you just want to explore the chemistry of a reaction, the net ionic equation will give you the best picture. Full molecular/formula equations are important to understand what's being combined (macroscale), but net ionic equations describe the chemistry. For example, if I want to make some silver(I) carbonate solid, I can go into the stockroom and grab a bottle of silver(I) nitrate and a bottle of potassium carbonate, dissolve some of each in water, and combine the solutions to make a silver(I) carbonate precipitate as described by the following equation:
2 AgNO3(aq) + K2CO3(aq) --> Ag2CO3(s) + 2 KNO3(aq)
If I really want to describe the chemistry of this reaction, the potassium and nitrate ions aren't really doing anything. The only reason they're there is because I need to balance the charge of the silver(I) and carbonate ions in the solid reagents I get from the shelf. To describe the chemistry, I can (and probably should) use the net ionic equation:
2 Ag+(aq) + CO32-(aq) --> Ag2CO3(s)
Don't forget the old MC assignment (due tonight) and the new MC assignment (due Friday).
2008/09/19
Stoichiometry Friday
I'm posting this before class today because I am leaving town immediately following class. We will continue talking about stoichiometry, including limiting reagents and theoretical yields. I know this is going to sound familiar, but stoichiometry is all about practice, so start working on these things early and often.
There is a new MC assignment posted, due Monday.
Although Chem 150L is a separate course, I'll also take this opportunity to post a couple notes/reminders about lab.
1. Next week is the safety exam, be sure to review your notes and the PowerPoints of the safety lectures.
2. A few people still didn't have proper notebooks or goggles, make sure you have all of the required materials for lab. Also, writing in a lab notebook in pencil is not appropriate, regardless of the type of notebook you are using. Lab notebooks (for any class, not just chemistry) are intended to be a record of your activities in lab and are used to document any discoveries you make. These records should be kept in a manner more permanent than pencil.
3. With the nice weather this week, a number of people were wearing inappropriate footwear this week. You should only wear closed-toed shoes/boots to lab, no sandals, flip-flops, etc.
If you're looking for things to do (besides practicing stoichiometry problems) this weekend, there are a couple things I'm aware of:
1. The MSUM Volleyball team is at home Friday (7pm, vs. Bemidji) and Saturday (4pm, vs. UM-Duluth) at Nemzek.
2. The MSUM Soccer team is at home Saturday (11am, vs. Winona) and Sunday (1pm, vs. Upper Iowa), the soccer field is across the street north of the football field.
3. West Fest is happening this weekend in West Fargo, it's a community fair type event with a parade, car show, and other activities. For more info:
http://www.westfargochamber.com/Events/WestFest/tabid/66/Default.aspx
If anyone has other events or activities, post a comment. Have a good weekend.
There is a new MC assignment posted, due Monday.
Although Chem 150L is a separate course, I'll also take this opportunity to post a couple notes/reminders about lab.
1. Next week is the safety exam, be sure to review your notes and the PowerPoints of the safety lectures.
2. A few people still didn't have proper notebooks or goggles, make sure you have all of the required materials for lab. Also, writing in a lab notebook in pencil is not appropriate, regardless of the type of notebook you are using. Lab notebooks (for any class, not just chemistry) are intended to be a record of your activities in lab and are used to document any discoveries you make. These records should be kept in a manner more permanent than pencil.
3. With the nice weather this week, a number of people were wearing inappropriate footwear this week. You should only wear closed-toed shoes/boots to lab, no sandals, flip-flops, etc.
If you're looking for things to do (besides practicing stoichiometry problems) this weekend, there are a couple things I'm aware of:
1. The MSUM Volleyball team is at home Friday (7pm, vs. Bemidji) and Saturday (4pm, vs. UM-Duluth) at Nemzek.
2. The MSUM Soccer team is at home Saturday (11am, vs. Winona) and Sunday (1pm, vs. Upper Iowa), the soccer field is across the street north of the football field.
3. West Fest is happening this weekend in West Fargo, it's a community fair type event with a parade, car show, and other activities. For more info:
http://www.westfargochamber.com/Events/WestFest/tabid/66/Default.aspx
If anyone has other events or activities, post a comment. Have a good weekend.
2008/09/17
Test returned and started stoichiometry
Exams were returned in class today. If you did not take the exam but intend to continue in class please let me know, I will be forwarding names of those who are not continuing in class to the registrar next week. If you were not in class today to pick up your exam, I will have your exam with me on Friday in class. The average on the exam was 110/150.
We began talking about Chapter 4. Stoichiometry is all about balancing chemical equations, converting grams to moles and moles to grams. If you're struggling with balancing chemical formulas or these gram-mole/mole-gram conversions, you need to practice, practice, practice. We'll continue on Friday.
We began talking about Chapter 4. Stoichiometry is all about balancing chemical equations, converting grams to moles and moles to grams. If you're struggling with balancing chemical formulas or these gram-mole/mole-gram conversions, you need to practice, practice, practice. We'll continue on Friday.
2008/09/12
SI times and locations
I just noticed that Sara posted SI times and locations in a comment below, I'll repeat them:
Tuesday, LO 84, 1:30
Wednesday, BR 269, 5:30
Thursday, BR 268, 12:30
I hope that many of you are taking advantage of SI, regardless of your level of previous chemistry experience, it will help.
Tuesday, LO 84, 1:30
Wednesday, BR 269, 5:30
Thursday, BR 268, 12:30
I hope that many of you are taking advantage of SI, regardless of your level of previous chemistry experience, it will help.
Review day...
Today I answered questions in preparation for the exam on Monday. Be sure to look at the old exams on my web page to get an idea of the exam format and length. The front page of the exam has a periodic table and a number of physcial constants, take a look at what's available. If you have any questions, let me know, I will answer questions to this blog over the weekend.
A few policy/procedure notes/reminders for the exam on Monday:
1. No programmable calculators.
2. No cell phone calculators.
3. There must be at least 1 empty seat between you and your neighbor.
4. Turn off your cell phone. If your phone rings during the exam, you fail the course.
5. You are responsible for the polyatomic ions listed in Table 3.5, p.95 of the Tro textbook.
6. I do not expect you to memorize the whole periodic table, but I expect you to be able to use it. If you look at old exams, you will see that when I refer to an element I will often note the atomic number. This is to make it easier for you to find the element on the periodic table. For example, I don't expect you to know that rutherfordium has the symbol "Rf", but if I tell you that the atomic number of rutherfordium is 104, you should be able to find it very quickly on the periodic table and then be able to use the symbol, atomic mass, etc.
Good luck with your studying, let me know if there are questions.
A few policy/procedure notes/reminders for the exam on Monday:
1. No programmable calculators.
2. No cell phone calculators.
3. There must be at least 1 empty seat between you and your neighbor.
4. Turn off your cell phone. If your phone rings during the exam, you fail the course.
5. You are responsible for the polyatomic ions listed in Table 3.5, p.95 of the Tro textbook.
6. I do not expect you to memorize the whole periodic table, but I expect you to be able to use it. If you look at old exams, you will see that when I refer to an element I will often note the atomic number. This is to make it easier for you to find the element on the periodic table. For example, I don't expect you to know that rutherfordium has the symbol "Rf", but if I tell you that the atomic number of rutherfordium is 104, you should be able to find it very quickly on the periodic table and then be able to use the symbol, atomic mass, etc.
Good luck with your studying, let me know if there are questions.
2008/09/10
Organic compounds and balancing equations
Today in class we started talking about balancing chemical equations and we had a brief introduction to organic compounds. I'm not so concerned that you memorize all of the organic compounds we talked about today, but I wanted to go over some of the naming so that it's familiar when we use these substances in future examples.
In class on Friday we will be reviewing for the exam as long as necessary. If you have questions or topics for review, try to let me know ahead of time so I can prepare, or just come to class with questions. We will "review" as long as there is material to review, if we run out of review topics and problems we will start Chapter 4.
Sara will be leading an extra SI session to review for the exam at 11:30 on Friday.
In class on Friday we will be reviewing for the exam as long as necessary. If you have questions or topics for review, try to let me know ahead of time so I can prepare, or just come to class with questions. We will "review" as long as there is material to review, if we run out of review topics and problems we will start Chapter 4.
Sara will be leading an extra SI session to review for the exam at 11:30 on Friday.
2008/09/08
Mass % composition and formulas from %'s
Today we looked at percent composition and a couple ways to use percent composition to determine empirical and molecular formulas. In one of the problems I worked through on the board, I made a slight mistake, so I'll try to clear that up here. We worked through a problem where we came up with an empirical formula of CH_2_. The molar mass of this substance was stated to be 84 g/mol. So the question here is, what is the molecular formula of this substance? The mass of the empirical formula is 14 g/mol (OK, 14.027 g/mol, but that's close enough to 14 g/mol that we can round...). Since the molecular formula must be a multiple of the empirical formula, then we know that 14*(some whole number)=84. Solving, 84/14 = 6, so the molecular formula must be 6x the empirical formula, or C_6_H_12_.
Check out the Natural Sciences Research Night this evening at 5:30 in SL104. A number of faculty in the natural sciences will present brief descriptions of their research, so if you're interested in doing research this is a great opportunity to learn about what's going on.
Check out the Natural Sciences Research Night this evening at 5:30 in SL104. A number of faculty in the natural sciences will present brief descriptions of their research, so if you're interested in doing research this is a great opportunity to learn about what's going on.
2008/09/05
Moles, compound formulas, etc.
Today in class we talked about different types of compounds (ionic, molecular/covalent) and how to write electronically-balanced formulas for ionic compounds and balanced formulas for molecular/covalent compounds. Read/review the sections in your textbook on nomenclature. You will be responsible for all of the polyatomic ions listed in Table 3.5, page 95 of your text.
We also worked on a problem set in class. I've posted the problem set (as well as an answer key) on my web site (www.mnstate.edu/bodwin) on the Chem 150 page. Some of the questions on the problems set were intended to be challenging, so if you struggled with some of the questions that's a good thing, it will help you (and me) figure out where we all need to work a little more.
There are 2 new MC assignments posted, I was going to post one today and the other on Monday, but we've already touched on all the topics so I put them both up to give you more time to work on them. Do not wait until the last minute to do these assignments! We have already talked about everything except the last 2 questions in the second assignment, so you should be able to get a good start on these as soon as you have time to use a computer.
Have a good weekend and let me know if there are any problems/questions.
We also worked on a problem set in class. I've posted the problem set (as well as an answer key) on my web site (www.mnstate.edu/bodwin) on the Chem 150 page. Some of the questions on the problems set were intended to be challenging, so if you struggled with some of the questions that's a good thing, it will help you (and me) figure out where we all need to work a little more.
There are 2 new MC assignments posted, I was going to post one today and the other on Monday, but we've already touched on all the topics so I put them both up to give you more time to work on them. Do not wait until the last minute to do these assignments! We have already talked about everything except the last 2 questions in the second assignment, so you should be able to get a good start on these as soon as you have time to use a computer.
Have a good weekend and let me know if there are any problems/questions.
2008/09/03
Wednesday.....
Today in class we discussed the development of the Periodic Table, calculated the isotopic abundance of a mixture of nitrogen-14 and nitrogen-15, and developed the concept of the mole as a counting unit. If you're following along in the textbook, we've pretty much finished Chapter 2. Now, you're probably saying to yourself, "Hey, it's the 4th day of class and we've already burned through 2 chapters?!?!?!?!?!?" Yes, the first two chapters fly by VERY quickly, this is largely because Chapters 1 & 2 are a bit of a potpourri of little bits and pieces. If you've taken chemistry courses before, this should be review. If you've never had a chemistry class, this may seem to be a bit much. Regardless of your background, it's all about practice, practice, practice. We will be slowing down a bit as we move into Chapter 3 and beyond.
A few people have asked me about getting some help with the math involved in this course. This summer, I was made aware of a website that claims to address this very topic:
www.ChemReview.Net
I've looked over some of these tutorials, and they look like they should be helpful, so you might want to check it out. This website is a little more chemistry-specific, I'll do a little more digging to try and find a more general algebra tutorial. You can also come to me any time for help, either in person or via email.
Another resource is SI. Unfortunately, I forgot to jot down the location of tonight's SI session, so if someone could post that as a comment to this post it would be appreciated.
Also, tonight is the first Chem Club meeting of the year, 7pm in SL104. Come to the meeting to find out about what Chem Club is doing this year, what Chem Club can do for you, and what you can do for Chem Club. I've heard that there will be at least 1 interesting chemical demonstration at the meeting tonight.
Hmm, sounds like a good chemistry-related night. SI at 5:30, Chem Club meeting at 7.
A few people have asked me about getting some help with the math involved in this course. This summer, I was made aware of a website that claims to address this very topic:
www.ChemReview.Net
I've looked over some of these tutorials, and they look like they should be helpful, so you might want to check it out. This website is a little more chemistry-specific, I'll do a little more digging to try and find a more general algebra tutorial. You can also come to me any time for help, either in person or via email.
Another resource is SI. Unfortunately, I forgot to jot down the location of tonight's SI session, so if someone could post that as a comment to this post it would be appreciated.
Also, tonight is the first Chem Club meeting of the year, 7pm in SL104. Come to the meeting to find out about what Chem Club is doing this year, what Chem Club can do for you, and what you can do for Chem Club. I've heard that there will be at least 1 interesting chemical demonstration at the meeting tonight.
Hmm, sounds like a good chemistry-related night. SI at 5:30, Chem Club meeting at 7.
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