yo calling all chemistry people....help with this problem which i am sure is easy and

[IronReload04]

I am sure you guys have seen this before.



Calcium crystallizes into a face centered cubic unit cell. you know the volume of this unit cell. you have this large block of calcium in which you know its volume as well. How many atoms are in this large block of calcium.


my first move was to just take the large block volume, divide by unit cell volume, and multiply by 4 because 4 cells are in a face centered unit cube. That is dead wrong.



As I have been typing this, I have been pondering about using the masses instead of volume to do this. I already have the density of the calcium unit cell figured out which would obviously be the density of the calcium block as well, and perhaps you can just divide the masses as i had tried dividing volumes (4).

well, i will only have 2 tries after this idea. so i would be thankful for help

[IronReload04]

awesome, just think i figured it out and am gonna try it....love how writing things out like that helps.

[IronReload04]

nope....used density to figure out mass of block...than divided by mass of unit cell and i am incorrect...

2 tries left.



edit- ****

[RuhlFreak55]

umm i believe you have to use avogadros number

[GusInc]

basically divide the volume of the block by the volume of 1 atom of clacium then multiply by avogadros number

block volume
____________ X Avogadros # = atoms
atom volume

[BuffedGuy]

Well, E = MC^2, so then just divide by 3.14, then raise it all to the log of the inverse of the reciprocal, get some avocados, and multiply all of that by zero.

[IronReload04]

basically divide the volume of the block by the volume of 1 atom of clacium then multiply by avogadros number

block volume
____________ X Avogadros # = atoms
atom volume

yeah.....


THe way i figured it out it was.

use the density from the calcium unit cell. use that density and the volume of the block to figure out mass. than mass converted to moles times ava G.



But I really do thank you for your input. Because it is always good to know multiple ways of doing things because you never know exactly what is going to be given in a problem.

thanks to all

[rich1234]

Well, E = MC^2, so then just divide by 3.14, then raise it all to the log of the inverse of the reciprocal, get some avocados, and multiply all of that by zero.

i lol'd in real life

[thegodfather]

Thank you for posting this, causing me to have flashbacks of my chemistry induced Post Traumatic Stress Disorder....I'm gonna go pop a few zoloft now.....dickhead...

[Matt]

Good lord i shouldnt be in this thread... Its hurting my head..

[IronReload04]

Thank you for posting this, causing me to have flashbacks of my chemistry induced Post Traumatic Stress Disorder....I'm gonna go pop a few zoloft now.....dickhead...

lol dude. I hear ya. This is the freshman chem series that you take if you are pre-med or pre professional anything.



I got buried my freshman year. this class actually made me quit and I swear i had never felt so defeated in my life. my book was all torn apart from being thrown at the wall repeatedly. but i went back to it after quitting and I am just going back retaking classes I did shitty in now. I am acing em this time around. BUt i am not going to lie. I am an upper classman and these classes take a tremendous amount of preperation, they are tedious and challenging, but A's are possible with the right kind of time and commitment put in.

[thegodfather]

lol dude. I hear ya. This is the freshman chem series that you take if you are pre-med or pre professional anything.



I got buried my freshman year. this class actually made me quit and I swear i had never felt so defeated in my life. my book was all torn apart from being thrown at the wall repeatedly. but i went back to it after quitting and I am just going back retaking classes I did shitty in now. I am acing em this time around. BUt i am not going to lie. I am an upper classman and these classes take a tremendous amount of preperation, they are tedious and challenging, but A's are possible with the right kind of time and commitment put in.

Im applying to medical school, I feel your pain...

[IronReload04]

Im applying to medical school, I feel your pain...

for sure. medical field is where its at.

[thegodfather]

for sure. medical field is where its at.

To be honest, the medical field might be where its at, but being a physician is certainly not. If I could go back to freshmen year and do everything over again I would have majored in nursing and then went the CRNA route. It's excellent pay $150,000-$200,000, with a quarter of the liability, half the debt, half the amount of schooling, and no 4-7 year residency where you are paid like a migrant worker and basically a slave.

Those are the cold hard facts. There are so many obstacles to becoming a physician, that if you want a good quality of life with a much smaller personal investment there are better options. Of course it is too late now since Im graduating 14 weeks from now, and I know I'll be happy with what Im doing. I just know that there existed a better option to having a good life and securing a 6 figure income.

[Kale]

My brain hurts !!

[scibble]

each cell unit volume is comprised of four atoms (due to the overlapping atoms between adjacent unit cells), so take the volume of the large block, divide that by the volume of the unit cell, and you get the total number of unit cells. multiply that by four to get the total number of atoms.

there is a discrepancy in reality since the four-atom-per cell number is really only for the internal cells completely surrounded by other cells, but i believe that since as the block under consideration gets larger, the surface area (error with respect to the above assumption) grows by power of 2, whereas the volume (and thus number of internal cells) grows by power of 3, so with a large block the error is probably small enough to become insignificant.

[Flagg]

My brain actually hurts from cramming a stupid amount of Earth and Ocean system science stuff over a short period of time. I don't care about zooplanktons or cocolithophores or how many thousands of years the poles switch, anymore.

[thegodfather]

My brain actually hurts from cramming a stupid amount of Earth and Ocean system science stuff over a short period of time. I don't care about zooplanktons or cocolithophores or how many thousands of years the poles switch, anymore.

Exactly the reason it is pointless to major in one of the sciences if you want to goto medical school. You save yourself a lot of time and energy learning useless shit you will never use, and have a much more enjoyable college experience by taking a cake major and just fulfilling the pre-reqs. Of course, if you want to do any kind of research in the future then it makes sense to take a science major, but otherwise its a big friggin waste of ones time...

[BuffedGuy]

To be honest, the medical field might be where its at, but being a physician is certainly not. If I could go back to freshmen year and do everything over again I would have majored in nursing and then went the CRNA route. It's excellent pay $150,000-$200,000, with a quarter of the liability, half the debt, half the amount of schooling, and no 4-7 year residency where you are paid like a migrant worker and basically a slave.

It takes at least eight years to become a CRNA: four years of nursing school, two years experience as an RN, and then two years masters in nurse anesthesia. Starting salary is about $110,000/yr. With 10-20 years of experience, average salary is $130,000/yr. After 20+ years, it is $140,000. (source; http://www.payscale.com/research/US/..._(CRNA)/Salary )

I think that you might make a comparison between CRNA's and primary care physicians. But with medicine, it really depends on what field you pursue. The anesthesiologist that a CRNA works under, for example, earns on average $350,000. Do the right fellowship and that number goes up. But yeah, the more years you put in for residency/fellowship, the higher it goes; a trade-off.

I'm not saying you're wrong. I am just saying it is a debatable issue.

[IronReload04]

To be honest, the medical field might be where its at, but being a physician is certainly not. If I could go back to freshmen year and do everything over again I would have majored in nursing and then went the CRNA route. It's excellent pay $150,000-$200,000, with a quarter of the liability, half the debt, half the amount of schooling, and no 4-7 year residency where you are paid like a migrant worker and basically a slave.

Those are the cold hard facts. There are so many obstacles to becoming a physician, that if you want a good quality of life with a much smaller personal investment there are better options. Of course it is too late now since Im graduating 14 weeks from now, and I know I'll be happy with what Im doing. I just know that there existed a better option to having a good life and securing a 6 figure income.

yeah....good stuff there. THat is actually something I have seriously been considering. nursing for a couple years and going back to grad school for something more. i got some options for hte time being

[IronReload04]

each cell unit volume is comprised of four atoms (due to the overlapping atoms between adjacent unit cells), so take the volume of the large block, divide that by the volume of the unit cell, and you get the total number of unit cells. multiply that by four to get the total number of atoms.

there is a discrepancy in reality since the four-atom-per cell number is really only for the internal cells completely surrounded by other cells, but i believe that since as the block under consideration gets larger, the surface area (error with respect to the above assumption) grows by power of 2, whereas the volume (and thus number of internal cells) grows by power of 3, so with a large block the error is probably small enough to become insignificant.

That was actually my first move and I promise you it did not work.

"take the volume of the large block, divide that by the volume of the unit cell, and you get the total number of unit cells. multiply that by four to get the total number of atoms."



What I did was use the given radius of the unit cell. Figured out the density of calcium with that. Take the density of calcium and the given volume of the large block to solve for mass of the large block. convert that mass to moles and multiply by avagadro.

so

density of calcium= m/v

mass/molar mass calcium * avagadro


thats the way my friend.




edit....because if you think about it, their are 4 atoms in a unit cell, but that is indeed not the whole story. theirs like 8 corner atoms to consider than the 6 faces etc etc. thats probably why that doesnt work.

[scibble]

i'm curious. please let me know what the two results are,

that is, what's the right answer, and what's the result using the "dead wrong" method?

just curious how far off they are

[IronReload04]

your way, which was my very first try gave me an answer of 2.31e24 atoms. this was incorrect.


my way- with mass to moles times avaG. was 1.49 e25 atoms and is correct.

edit
if you think about it, yeah, their is technically 4 atoms in a unit cell. but in a unit cell, their is 8 corner atoms and than 6 face atoms. so 8/8 (1) + 6/2 (3) but really more like 14 atoms "sort of" I am guessing that has alot to do with why your way and my first way did not work. Belieive me man, it had me baffled and is why i made this thread in the first place. but i was sitting in anouther class several hours after making this thread and the answer just hit me out of know where its so logical.

[MuscleScience]

To be honest, the medical field might be where its at, but being a physician is certainly not. If I could go back to freshmen year and do everything over again I would have majored in nursing and then went the CRNA route. It's excellent pay $150,000-$200,000, with a quarter of the liability, half the debt, half the amount of schooling, and no 4-7 year residency where you are paid like a migrant worker and basically a slave.

Those are the cold hard facts. There are so many obstacles to becoming a physician, that if you want a good quality of life with a much smaller personal investment there are better options. Of course it is too late now since Im graduating 14 weeks from now, and I know I'll be happy with what Im doing. I just know that there existed a better option to having a good life and securing a 6 figure income.

Every MD I talked to told me it wasnt worth it, So I didnt do it.

[scibble]

congrats on finding the right answer

rock on man

[IronReload04]

congrats on finding the right answer

rock on man

lol thanks man....just out of nowhere, i am learning about biology and it hit me to do something as simple as d=m/v moles avaG

[BuffedGuy]

Every MD I talked to told me it wasnt worth it, So I didnt do it.

Yeah, but a lot of them would do it all over again, if really given the chance. Having said that, dentistry is probably a better route. My dentist cousin in his twenties is driving around in a corvette. I would seriously have considered dentistry if I had to do it all over again, although I don't know for sure which I would've picked. Would need to soul search for that.

[scibble]

dentistry is where it's at, i agree. great income, much less liability, less insurance hassles, et cetera

[Bojangles69]

Well, E = MC^2, so then just divide by 3.14, then raise it all to the log of the inverse of the reciprocal, get some avocados, and multiply all of that by zero.

That really is fvcking funny lol

[thegodfather]

Every MD I talked to told me it wasnt worth it, So I didnt do it.

Yea, I'm friends with several and they have said the same thing, but I'm still doing it. The important thing to remember about nursing is that the schooling costs much less than a medical education. In addition during the 2 years working in critical care, a nurse with overtime can earn around $80,000/year, allowin the person to pay down any student loan debt that they have before going back for their 2 year masters program for CRNA.

A student who majors in anything aside from nursing to go onto medical school cannot get a job paying anywhere near that. They will have 4 years of undergrad debt, on top of 4 years of medical school debt. They will go onto a residency program where they will make between $12-$14 dollars an hour, and they will have to deferr their loans while doing so, meaning that their interest on the loans will be compounding each month. The very shortest residency+fellowship programs is 4 years. If we are talking about Anesthesiology it is a 2 year residency followed by a 2 year fellowship.

Additionally, if you get your RN from a school without getting your bachelors (you can do this in 3 years time), you can then earn your bachelors online in 9 months, and you are able to work during that time.

Lets look at the testing process...

From undergrad, a future med student needs to take the MCAT, possibly one of the hardest tests a person will take. After the long and expensive interview process they get an acceptance. Once in med school they will need to take the USMLE Step 1, which will be the determining metric in what choices they will have as far as residency. Before graduating they will take USMLE Step 2, and Step 3. None of those tests are cake walks. They do their residency and fellowships, and then they are ELIGIBLE to sit for the boards in that specific specialty.

From undergrad, a person pursuing nursing will take the NET test, a non-specific test that just measures a person ability in various areas but not science related. They will rely on their GPA and a less strenuous interview process. From there the only big test they will take will be the state boards (NCLEX). After that they can get hired and start making $60,000/yr working 3 - 12 hour shifts per week and with almost no liability for malpractice. 2 years working in critical care as a nurse paying down student loans, then onto a 2 year masters course for CRNA, at the max another $40,000 in debt..Thats less than it costs for ONE YEAR of medical school. The student graduates CRNA and even if they start at $110,000 a year, they do no residency, and they are financially well ahead of the game, and they work 40-60 hours per week.

If you compare the relative number of hours that high paying specialties pull in to how many hours they are actually working at the hospital or on call at home, they make much less than the numbers seem to indicate. I'm not arguing that doctors dont live well, they certainly do, but they are not nearly as well off as many think. If you are in ANY surgical specialty you will most likely never in your career work less than 80 hours per week, thats a fact.

[DSM4Life]

Not sure but i know how to make a volcano erupt .....

[auslifta]

Not sure but i know how to make a volcano erupt .....

lmao

[MuscleScience]

Yea, I'm friends with several and they have said the same thing, but I'm still doing it. The important thing to remember about nursing is that the schooling costs much less than a medical education. In addition during the 2 years working in critical care, a nurse with overtime can earn around $80,000/year, allowin the person to pay down any student loan debt that they have before going back for their 2 year masters program for CRNA.

A student who majors in anything aside from nursing to go onto medical school cannot get a job paying anywhere near that. They will have 4 years of undergrad debt, on top of 4 years of medical school debt. They will go onto a residency program where they will make between $12-$14 dollars an hour, and they will have to deferr their loans while doing so, meaning that their interest on the loans will be compounding each month. The very shortest residency+fellowship programs is 4 years. If we are talking about Anesthesiology it is a 2 year residency followed by a 2 year fellowship.

Additionally, if you get your RN from a school without getting your bachelors (you can do this in 3 years time), you can then earn your bachelors online in 9 months, and you are able to work during that time.

Lets look at the testing process...

From undergrad, a future med student needs to take the MCAT, possibly one of the hardest tests a person will take. After the long and expensive interview process they get an acceptance. Once in med school they will need to take the USMLE Step 1, which will be the determining metric in what choices they will have as far as residency. Before graduating they will take USMLE Step 2, and Step 3. None of those tests are cake walks. They do their residency and fellowships, and then they are ELIGIBLE to sit for the boards in that specific specialty.

From undergrad, a person pursuing nursing will take the NET test, a non-specific test that just measures a person ability in various areas but not science related. They will rely on their GPA and a less strenuous interview process. From there the only big test they will take will be the state boards (NCLEX). After that they can get hired and start making $60,000/yr working 3 - 12 hour shifts per week and with almost no liability for malpractice. 2 years working in critical care as a nurse paying down student loans, then onto a 2 year masters course for CRNA, at the max another $40,000 in debt..Thats less than it costs for ONE YEAR of medical school. The student graduates CRNA and even if they start at $110,000 a year, they do no residency, and they are financially well ahead of the game, and they work 40-60 hours per week.

If you compare the relative number of hours that high paying specialties pull in to how many hours they are actually working at the hospital or on call at home, they make much less than the numbers seem to indicate. I'm not arguing that doctors dont live well, they certainly do, but they are not nearly as well off as many think. If you are in ANY surgical specialty you will most likely never in your career work less than 80 hours per week, thats a fact.

One of my good buddies back home is a CRNA, it was hard to get in and pretty hard schooling but he makes bank and really enjoys what he does. He worked as a critical care nurse before that and made ok money. Now he makes great money and works great hours. I wish I would have done that route my self.

[IronReload04]

Godfather.......Musclescience


I am going to talk to my guidance counselor asap about nurse crna. its sounds ****ing bad ass

[scibble]

Lets look at the testing process...

From undergrad, a future med student needs to take the MCAT, possibly one of the hardest tests a person will take. After the long and expensive interview process they get an acceptance. Once in med school they will need to take the USMLE Step 1, which will be the determining metric in what choices they will have as far as residency. Before graduating they will take USMLE Step 2, and Step 3. None of those tests are cake walks. They do their residency and fellowships, and then they are ELIGIBLE to sit for the boards in that specific specialty.

If you compare the relative number of hours that high paying specialties pull in to how many hours they are actually working at the hospital or on call at home, they make much less than the numbers seem to indicate. I'm not arguing that doctors dont live well, they certainly do, but they are not nearly as well off as many think. If you are in ANY surgical specialty you will most likely never in your career work less than 80 hours per week, thats a fact.

i disagree about the importance of the USMLE. Granted I did well on all the tests from MCAT through IM board exam, but i dont think it limits you in residency. Most important is your clinical rotations and recommendations you get from there, and your grades overall. Obviously, you dont want to suck balls on the USMLE exams.

i made 30 to 35 K per year as a resident. i spent three years in residency. and hell no i didn't put my debt payments on hold. i paid toward my med school debt all the way through, you just have to live modestly

this is not to say i disagree with you overall. in general you are correct about nursing vs. med school. i'm just nit picking on a few points.

[T_Own]

scibble, 30k a year is only $15 an hour, assuming only a 40hr week. if you work more than that, the pay goes down to what thegodfather said (12-14/hr) but still comes out to 30k a year. and thats living modestly on its own, let alone paying off loans with that too.

i thought about doing the doctor thing, but malpractice insurance is ridiculous, some of the dr's i know in PA would be paying like 250k a year just for the insurance... so take that out of what you make and you can only be doing so well. and even with the insurance, if you screw up you're gonna get hit hard legally so they were never really content it seemed. its still seems like it would be a great job but it comes with a lot of strings attached (i guess like all the high paying jobs...)

also, i know a good amount of nursing students at school who agree with thegodfather, but then again, these aren't the type of kids you would see as doctors so i think they KNOW its the easy way out and so they still don't take it seriously enough (one of my good friends failed his junior year nursing class)

but to that problem, the mass to moles way was the first thing i thought of, but then again that was pretty much the point of AP chem (most i've had so far) besides acids..

[scibble]

scibble, 30k a year is only $15 an hour, assuming only a 40hr week. if you work more than that, the pay goes down to what thegodfather said (12-14/hr) but still comes out to 30k a year. and thats living modestly on its own, let alone paying off loans with that too.

i thought about doing the doctor thing, but malpractice insurance is ridiculous, some of the dr's i know in PA would be paying like 250k a year just for the insurance... so take that out of what you make and you can only be doing so well. and even with the insurance, if you screw up you're gonna get hit hard legally so they were never really content it seemed. its still seems like it would be a great job but it comes with a lot of strings attached (i guess like all the high paying jobs...)

also, i know a good amount of nursing students at school who agree with thegodfather, but then again, these aren't the type of kids you would see as doctors so i think they KNOW its the easy way out and so they still don't take it seriously enough (one of my good friends failed his junior year nursing class)

but to that problem, the mass to moles way was the first thing i thought of, but then again that was pretty much the point of AP chem (most i've had so far) besides acids..

first, you'll notice as i mentioned that i was arguing only specific points and said that i agreed with everything else. (2) thanks for the math lesson (3) i pay 5K insurance per year. (4) during residency you dont pay for your malpractice premium, that's covered by your program and if you work for a group or hospital that's covered as a benefit. (5) you are giving a skewed example of 250 K. Yes there are specialties in some states where someone has to pay that. but it's not the average for all specialties and varies greatly from state to state. Again, i make six figures and pay only 5000 dollars a year in premiums. The most my specialty would ever have to pay with a clean record is 9500.

My 30K per year btw was over ten years ago. and it's a simple fact. i was able to live in an apartment and continue making loan payments.

[T_Own]

the only part that was aimed at you was the first paragraph... so you can tone it down a little bit.

[scibble]

hahaah i was waitin. just statin the facts ma'am

[BuffedGuy]

Again, i make six figures

The goal should be seven, not six. No doctor makes less than six figures.

As for me, I don't care that much about how much money, as long as I can work 2-3 days a week only.

By the way, I think the reported incomes for doctors are heavily under-reported. My friend just finished his internal medicine residency and he makes $15,000 per month in bonuses alone. (He is a hospitalist.) And he is a lazy butt who gets off at like 4 pm almost every day.