I'm Procrastinating

[Michele 1]

I have a chemistry test on Tuesday. I should be studying, trying to figure out how to draw electon dot thingies, and memorizing compounds and ions. And I'm procrastinating. Don't mean to, but there's always something else I can do. Chemistry is soooooooo bothersome...I don't understand it very well, and I don't like it too much...combine those, and you get procrastination.

I'll probably decide to study before I decide to clean house...but it'll be a close call.

Sigh...I just can't get started.

Ciels-
Michele

~Do Angels keep the dreams we seek
While our hearts lie bleeding?~

[LisaH 0]

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I have a chemistry test on Tuesday. I should be studying, trying to figure out how to draw electon dot thingies, and memorizing compounds and ions. And I'm procrastinating. Don't mean to, but there's always something else I can do. Chemistry is soooooooo bothersome...I don't understand it very well, and I don't like it too much...combine those, and you get procrastination.

I'll probably decide to study before I decide to clean house...but it'll be a close call.

Sigh...I just can't get started.

Ciels-
Michele

The house can wait

Be yourself!
MooOOooOoo

[Squeak 17]

My house was spotless, before any University study occured

You are not now, nor will you ever be, good enough to not die in this sport (Sparky)
My Life ROCKS!
How's yours doing?

[Unstable 9]

Me too. I have to give a 20-something minute talk tomorrow and I'm reading the Poynters manuals and posting on DZ.com. HA!

=========Shaun ==========

[willard 0]

Ah yes, Lewis structures. I remember working those out. It just takes practice and repetition. Keep at it and you'll learn them. Do a few each morning and some more each evening. Better a few short sessions than one long session.

Get a good understanding of ions, cations, and their interactions. Much, if not most, of what lies ahead of you will require a good basic understanding of what's going on.

I've been through those courses and feel your pain. But this is not a good time to let yourself get lazy, though it is very easy to do so. Hit the books, get the basics down, and you will find that later on your job will be easier and you will be able to get your assignments done much quicker. In other words, a little extra effort now will save a lot of effort later.
(I'll betcha a case of beer that I hated chem more than you do )

[Michele 1]

Squeak, my house is never spotless. However, if I keep procrastinating, it just might get close! ROFL.

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I'll betcha a case of beer that I hated chem more than you do

Oh, dear...you'd lose.

Mr. Gifford. Squirelly eyed, waggly haired, thick cokebottle glasses wearing, tall skinny geek. Made fun of me in class during mole discovery. This was high school...I hated chemistry because of him. Failed it. Can't shake the whole "you're not as smart as you think, Michele" and "don't let her touch the chemicals; she'll blow up the place" comments...which, at 16, are pretty harsh comments to overcome.

No, you don't hate chemistry nearly as much as I do. my stomach turned when I read cations...

Sigh.

But you're right - this is foundational stuff, and I need to get it solid. I'm still procrastinating, but that's gotta stop.

Ciels-
Michele

~Do Angels keep the dreams we seek
While our hearts lie bleeding?~

[Icon134 0]

Chemists are merely Physists applying rules instead of science... or at least I told my academic advisor this the other day (who is btw a phyisical chemist... )

good luck on the test... if you need help let me know... I wasn't too bad at Lewis dot stuctures...

Livin' on the Edge... sleeping with my rigger's wife...

[Michele 1]

As long as I remember to make the central/skeleton atom full, then I'll be all right. I don't always remember that, though.

You could give me an easy, simple explanation of sigfigs, though...the ones I've been finding have got to be the most bizarre rules and explanations I've heard - far worse than what I remember my professor telling us. Either that, or I fell asleep and managed to miss something. Sigh.

Bleck.

Ciels-
Michele

~Do Angels keep the dreams we seek
While our hearts lie bleeding?~

[Icon134 0]

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You could give me an easy, simple explanation of sigfigs, though...the ones I've been finding have got to be the most bizarre rules and explanations I've heard - far worse than what I remember my professor telling us.

I've never heard the term sigfigs (I'm assuming that what you are refering to is Signficant Figures)

There appears to be an explaination here that isn't too bad...

http://dbhs.wvusd.k12.ca.us/webdocs/SigFigs/SigFigRules.html

The most difficult thing to deal with wrt significant figures are zeros.

First trailing zeros before the decimal when there isn't anything after the decimal (e.g. 3450) aren't significant thus the number above has three significant figures.

Second, if there are numbers both before and after the decimal any zeros on the end will be significant. (e.g. if the number above is changed to 3450.0 then the number of significan figures has changed from three to 5.)

Third, if there are no nonzero digits to the left of the the decimal then the zeros to the left of the 1st non zero term are NOT significant figures. e.g. if we divide the number above by 100,000 it becomes 0.034500 but the number of significant figures doesn't change there are still 5 significant figures.

I really hope this doesn't confuse you more...

Livin' on the Edge... sleeping with my rigger's wife...

[Michele 1]

Nope, that seems pretty clear cut to me. However...now the tricky part. When dealing with formulas that have different numbers in their sigfigs, how do you know which ones go in the freaking stupid answer?

And how come in 3450, the zero isn't significant? It changes the value significantly (har har...kay, now I'm just being stupid and tired). But that's got me kerflummoxed.

Icon, you're cool for helping me. And yes, sigfigs are significant figures, but you'd figured that out significantly earlier. Man, I need to sleep....

I will be studying tomorrow, I am certain. I have a study group at 6 with my lab partners (all brilliant; I'm the dead weight on this team...), so hopefully I will understand more of it tomorrow evening.

Ico n, I really appreciate this, more than you'd realize. I need to get a good grade here, and I feel like I'm stumbling already - and it's only 2 weeks in. Sigh...

Thanks for all the encouragement - here and in pms. This site is cool...homework help, camaraderie, and just good old fashioned friendships.

Ciels-
Michele

~Do Angels keep the dreams we seek
While our hearts lie bleeding?~

[Icon134 0]

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Nope, that seems pretty clear cut to me. However...now the tricky part. When dealing with formulas that have different numbers in their sigfigs, how do you know which ones go in the freaking stupid answer?

as I understand it the general rule of thumb (and this is where it can get complex) is that the answer shouldn't have any more significant figures then the significant figures of the consituants.

for example if I add 30.24 to 21.1 then the answer can only have three significant figures because even though 30.24 has four significant figures 21.1 only has three. (does that make sense)

The same goes for subtraction, multiplication, and division.

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And how come in 3450, the zero isn't significant? It changes the value significantly (har har...kay, now I'm just being stupid and tired). But that's got me kerflummoxed.

this might get a little confusing... so bear with me...

The concept of significant figures comes into play primarily due to the inacuracies of measurements. For example if you are measuring a block of wood using a ruler that has increments of say 10 milimeters (mm) (which is 1 centimeter (cm) but for the sake of argument/explaination I want to work in mm)

so you measure the block and it has a length of 3450 mm. (which has 3 siginficant figures because our unit of measure is 10 mm incriments.)

so now I go get a different ruler that instead has increments of mm and I measure the block of wood again. This time the length is measured to be 3450 mm now in this case the 3450 mm has four significant figures because the measurement device has units of milimeters. Now usually if the zeros before the decimal are going to be counted as significant figures then people will indicate that (if I remember correctly they'll usually put a bar or something above zeros that are significant... typically though a scientist is going to know if the zeros are significant or not depending on the measurement technique, equipment error, etc.

whew... that was kind of long winded...

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And yes, sigfigs are significant figures, but you'd figured that out significantly earlier.

google is my friend
again... I hope I haven't confused... and please if I'm wrong someone please correct me. (its been a while since I've been in undergraduate Chemistry... )

Livin' on the Edge... sleeping with my rigger's wife...

[Squeak 17]

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Nope, that seems pretty clear cut to me. However...now the tricky part. When dealing with formulas that have different numbers in their sigfigs, how do you know which ones go in the freaking stupid answer?

Ciels-
Michele

your answer can not have any more sigfigs than the smallest number of sigfigs in your question.

so if one part of your Q has 4 sigfig and another part only 2 you answer can only have 2

You are not now, nor will you ever be, good enough to not die in this sport (Sparky)
My Life ROCKS!
How's yours doing?

[Michele 1]

Thanks, Squeak and Ico n. I am starting to get that. Between the memorization of ions, and the electron dot/Lewis structures, I'm getting tangled in my brain. I've got my lab partner study group - they're saving my ass; usually it's the other way 'round... - in about an hour, and then we're all getting dinner. After that, it's back to the chapter tests in the study guide, and going over the problems again and again (naming compounds and structures is ever so much fun....NOT!), doing conversions until I cry (word problems suck!), and then perhaps some sleep...

Maybe by Tuesday I'll understand enough to pass...

I do appreciate the help, you all. Thanks...sorry I'm such a stupidhead.

Ciels-
Michele

~Do Angels keep the dreams we seek
While our hearts lie bleeding?~

[willard 0]

Sig figs can get confusing. I go by a few simple rules.
1. Zeros at the beginning of a number are never significant. They only show the position of a decimal point.
2. Zeros between non-zero digits are always significant.
3. Zeros at the end of a number and zeros after the decimal point are always significant.
4. When a number ends in zeros but has no decimal point, the zeros may or may not be significant.
Consult your instructor on this one.

Calculations.
Pretty easy, really. When multiplying or deviding the answer cannot contain more sig figs than the measurement with the fewest sig figs. example....(6.221)x(5.2)=32.3492, round off to 32
When adding or subtracting you cannot have more sig figs after the decimal than the measurement with the fewest sig figs after the decimal. 20.4+1.322+83=104.722, round off to 105

Just like the Lewis structures, sig figs become second nature from repitition. Keep practicing, they will come to you.

In these days of computers and calulators the importance of sig figs can become lost. When using a slide rule it was very important to be able to accurately count sig figs and round properly.

Keep up the good work!

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[Michele 1]

I've managed to get a decent handle on Lewis structures...not very fast at them, but generally correct. Now on to memorization of the things he wants us to memorize - polyatomic atoms.

Sigh...

Whatever gave me the idea I could do this class on a 5 week time schedule?? Good grief, my head must've been firmly planted up my......

Ciels-
Michele

~Do Angels keep the dreams we seek
While our hearts lie bleeding?~

[Icon134 0]

I'm sure you'll do fine.

Livin' on the Edge... sleeping with my rigger's wife...

[willard 0]

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I've managed to get a decent handle on Lewis structures...not very fast at them, but generally correct. Now on to memorization of the things he wants us to memorize - polyatomic atoms.

Sigh...

Whatever gave me the idea I could do this class on a 5 week time schedule?? Good grief, my head must've been firmly planted up my......

Ciels-
Michele

Correct beats fast any day. Can't be wrong fast enough to get full credit.

[Michele 1]

All right, I just did 20 Lewis Structures in about 20 minutes. Much faster than yesterday...and I'm wondering if I messed up. LOL...I practiced them alot yesterday, and according to my notes, I have them all correct...so I'm wondering if something didn't click overnight. Would be the first time that happened, you know?

Now, on to conversions and fusion/heat, polyatomic atoms and the stuff I've just got to memorize...

Thanks for all the encouragement guys...I really appreciate it. I get so stressed about this sort of stuff...I'm just not a good test taker at all.

Ciels-
Michele

~Do Angels keep the dreams we seek
While our hearts lie bleeding?~