Chem Spring 2008

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Hi all,

Hoping to start a Chem study group for Spring 2008. I do not begin class until January 15th but figured I would see about getting a group together as soon as possible.

Im taking two chemistry's so my next test is tonight for the other class this on is much harder.

Two chemistry classes at the same time! Ack! Which ones?

I am waiting on my results from my o-chem exam and am on pins and needles. I hope the instructor will post the grades online as he did with the quiz so that we don't have to wait too much longer. I don't think I bombed, but I don't think I scored an A, either. Sigh.

Chemistry is my Achilles heel.

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I hate my teacher...just hate him...i've tried to deal but he is unworkable. Weds we had our 1st test. In the middle of it the fire alarm went off so we had to leave. He told us all to go home because we'd just be outside talking about what was on the test so he'd have to figure out what he was going to do. So I get an email last nite that he came up with some system for grading what was done and I got an F.

Oh, you poor tihing! How awful! Chem is tough enough without a teacher who makes ridiculous decisions like that! There is no way he can say what your final grade would have been on that test if you had been able to finish it. To give you an F based on what you had done so far is just unfair. I agree with Hotflashn's advice about going to the division head and presenting your case. You should be able to just drop the class without a "W" because of these unusual circumstances. If that doesn't work, and if it were me, I would get out of the class and take the W. The teacher sounds like a jerk, and there may be no way to salvage the rest of the semester at this point. I am so sorry you are stressed about this matter and all the other "stuff" going on in your life! :icon_hug: There's a hug for ya!

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I think that instructor is rediculous for penalizing your class grade due to a FIRE DRILL!!! I would definitely talk to the head of the department about that. Like that was really under your control.

Thanks to the person who posted all of those chem websites. I have bookmarked all of them and have used a few also.

Well, I have my second Basic Chem exam this coming Thursday. I am getting together with my lab partner this afternoon at the library to study. We are studying things like the atomic number, atomic mass, covalent and ionic bonding and on Tuesday will be covering the VESPR theory. This is where I am starting to get confused. Anyone have any good advice and/or resources on the VESPR theory and Formulas of Binary ionic compounds? The subscript switching is very confusing to me for some reason.:uhoh3:

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I think that instructor is rediculous for penalizing your class grade due to a FIRE DRILL!!! I would definitely talk to the head of the department about that. Like that was really under your control.

Thanks to the person who posted all of those chem websites. I have bookmarked all of them and have used a few also.

Well, I have my second Basic Chem exam this coming Thursday. I am getting together with my lab partner this afternoon at the library to study. We are studying things like the atomic number, atomic mass, covalent and ionic bonding and on Tuesday will be covering the VESPR theory. This is where I am starting to get confused. Anyone have any good advice and/or resources on the VESPR theory and Formulas of Binary ionic compounds? The subscript switching is very confusing to me for some reason.:uhoh3:

This is what we are working on also. While you're at the library look up the Cliffs Study Solver for Chemistry, I purchased it and it seems to help a lot on the things that I don't understand in class or that I don't understand in the class book. I'm going to make an appt for Mon to see a counsler prior to my class to see if I have any other options than to deal with this teacher till May.

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We are studying things like the atomic number, atomic mass, covalent and ionic bonding and on Tuesday will be covering the VESPR theory. This is where I am starting to get confused. Anyone have any good advice and/or resources on the VESPR theory and Formulas of Binary ionic compounds? The subscript switching is very confusing to me for some reason.:uhoh3:
You have to do VESPR theory in Chem I? You poor thing! Usually you run into that in organic chem. Anyway, here's a "fun" animation about VESPR theory:

http://chemmovies.unl.edu/ChemAnime/VS0EPRD/VS0EPRD.html

As for subscript switching in ionic compounds, it's easier if you think about creating a compound that is ELECTRICALLY NEUTRAL, so that all the charges on the elements add up to ZERO. Let's say you want to combine Barium with Chlorine. You know that Barium has a +2 charge on it (it's in Group 2 of the periodic table), and you know that Chlorine has a -1 charge on it, as do the other elements in Group 17. So before you figure out the compound you have BaCl, which is Ba2+ and Cl- (remember we don't write the number 1 in a charge). If you left it at that, the net charge on the compound would be +1, because +2 + (-1) = +1. As my Chem prof said last semester, Congratulations! You just blew up the world!:lol2:

The only way to make that compound neutral is to have TWO chlorines for a total charge of -2 on chlorine. So the formula has to be BaCl2 (2 is a subscript, but I can't make it look right on this screen). 1 Barium bonds with 2 Chlorines. That way, the compound is electrically neutral: +2 from the 1 Ba and -2 from the 2 Cl gives you a net charge of 0.

Once you do enough of these, you recognize immediately that Al3+ and O2- have to "switch subscripts" in order to make the compound electrically neutral: Al2O3. But once you understand the theory behind it, it's easier to know *why* it appears you're just switching subscripts.

If you're wondering how to remember which elements have which charges, you can just "know" some of them, like Group 1 (1+) and Group 2 (2+) and so on. But it's also easy to look at which Noble Gas the element "wants to be like". If you look at the element Barium on the periodic table (see http://webelements.com), it has 56 electrons (because it has 56 protons). Looking over at Group 18, you'll see that Xenon has 54 electrons. So you know right away that the most stable ion of Barium will be the ion in which it LOSES 2 electrons and takes on a +2 charge, because then Barium will be isolectronic with the nice, stable, happy Xenon. If you haven't learned all about the term isoelectronic and concepts underlying it (e.g. electron configuration), don't worry! You'll get there.

You can see my earlier post for some websites where you can practice creating and naming ionic compounds:

https://allnurses.com/forums/2671772-post116.html

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This is what we are working on also. While you're at the library look up the Cliffs Study Solver for Chemistry, I purchased it and it seems to help a lot on the things that I don't understand in class or that I don't understand in the class book. I'm going to make an appt for Mon to see a counsler prior to my class to see if I have any other options than to deal with this teacher till May.

Thanks. I purchased the Cliff Study Solver also. I hope things go well with the counseling appt. ;)

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You have to do VESPR theory in Chem I? You poor thing! Usually you run into that in organic chem. Anyway, here's a "fun" animation about VESPR theory:

http://chemmovies.unl.edu/ChemAnime/VS0EPRD/VS0EPRD.html

As for subscript switching in ionic compounds, it's easier if you think about creating a compound that is ELECTRICALLY NEUTRAL, so that all the charges on the elements add up to ZERO. Let's say you want to combine Barium with Chlorine. You know that Barium has a +2 charge on it (it's in Group 2 of the periodic table), and you know that Chlorine has a -1 charge on it, as do the other elements in Group 17. So before you figure out the compound you have BaCl, which is Ba2+ and Cl- (remember we don't write the number 1 in a charge). If you left it at that, the net charge on the compound would be +1, because +2 + (-1) = +1. As my Chem prof said last semester, Congratulations! You just blew up the world!:lol2:

The only way to make that compound neutral is to have TWO chlorines for a total charge of -2 on chlorine. So the formula has to be BaCl2 (2 is a subscript, but I can't make it look right on this screen). 1 Barium bonds with 2 Chlorines. That way, the compound is electrically neutral: +2 from the 1 Ba and -2 from the 2 Cl gives you a net charge of 0.

Once you do enough of these, you recognize immediately that Al3+ and O2- have to "switch subscripts" in order to make the compound electrically neutral: Al2O3. But once you understand the theory behind it, it's easier to know *why* it appears you're just switching subscripts.

If you're wondering how to remember which elements have which charges, you can just "know" some of them, like Group 1 (1+) and Group 2 (2+) and so on. But it's also easy to look at which Noble Gas the element "wants to be like". If you look at the element Barium on the periodic table (see http://webelements.com), it has 56 electrons (because it has 56 protons). Looking over at Group 18, you'll see that Xenon has 54 electrons. So you know right away that the most stable ion of Barium will be the ion in which it LOSES 2 electrons and takes on a +2 charge, because then Barium will be isolectronic with the nice, stable, happy Xenon. If you haven't learned all about the term isoelectronic and concepts underlying it (e.g. electron configuration), don't worry! You'll get there.

You can see my earlier post for some websites where you can practice creating and naming ionic compounds:

https://allnurses.com/forums/2671772-post116.html

Thanks for the information. It is beginning to make more sense. I think I need to practice them more also. Repetition, repetition, repetition..

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well when i went in on mon pretty much everyone had an f on the test so no one was happen. there's a girl in my class that's an honors student and she got a b and wasn't happy with that. wish i had those standards! anyway we voted to retake the test on weds. took it and i got a b! i was soo relieved! i didn't want to drop the class but if i did poorly i was going to. so i'm going to try and stick it out. i rescheduled my meeting with a counsler till tues because we had a big snow storm and i didn't want to go out not knowing what my test score was. i need to find out some other class requirements and discuss this teacher. thanks for all your support! :bugeyes:

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anyway we voted to retake the test on weds. took it and i got a b! i was soo relieved! i didn't want to drop the class but if i did poorly i was going to. so i'm going to try and stick it out.:bugeyes:

whew, what a relief. i am glad you got the option to retest. the other arrangement was so unfair! hopefully thing will be relaxed. hang in there.

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Thank you all for posting these help links. I am taking a PRE-Chemistry course right now (since I never had Chem in high school, back oh, 25 years ago!) You all are wonderful, I'm in awe! Thank you, thank you, thank you! I especially love chemfiesta.com! Wow!

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Specializes in Telemetry and Psych.
well when i went in on mon pretty much everyone had an f on the test so no one was happen. there's a girl in my class that's an honors student and she got a b and wasn't happy with that. wish i had those standards! anyway we voted to retake the test on weds. took it and i got a b! i was soo relieved! i didn't want to drop the class but if i did poorly i was going to. so i'm going to try and stick it out. i rescheduled my meeting with a counsler till tues because we had a big snow storm and i didn't want to go out not knowing what my test score was. i need to find out some other class requirements and discuss this teacher. thanks for all your support! :bugeyes:

congrats on your b!! yeah for you!! i'm really glad that you were able to retake the test. it would have been awful of your instructor to have you all keep the initial scores. makes you wonder if the instructors realize that it's a reflection on them as well as the students........

i have my second exam in chem monday night...nervous as heck to take it because i had been sick for 2 weeks with pneumonia...wish me luck all!!

thank you all for posting these help links. i am taking a pre-chemistry course right now (since i never had chem in high school, back oh, 25 years ago!) you all are wonderful, i'm in awe! thank you, thank you, thank you! i especially love chemfiesta.com! wow!

i too am very thankful for all that have posted sites and notes on here. they have been helpful for me! thank you to all!!!

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Specializes in Telemetry and Psych.

Bumping this back to the first page.

Hoping to find out tomorrow how I did on my second exam on Wednesday night. Will let you all know if the instructor gives us our results.

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