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Chemistry Help (calories)

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Sean...M
Posts: 2450 - Karma: 14
Okay so i have my final tomorrow so I'm studying at the moment and I'm totaly stuck on this question. I usually hate doing this but i've already searched google and hopefully one of you guys can help me out.

assessment/questiondb/GradedInclude_mc.jsp applicationframework/CommonHeader.jspi applicationframework/contextPath.jspi Since a calorie is defined as the amount of energy required to heat 1 g of water up by 1oC, a Calorie will raise
1 liter (1000 g) of water by 1o C. To what temperature can 2 liters of water at 25oC be
raised with the energy contained in a handful of raisins (25 Calories).

The answer is 37.5oC but I have no idea how to get it.


Dec 11 2008 5:16PM
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user098123
Posts: 6072 - Karma: 18
There are some calorie equations but I can't really remember them haha.

Anyways, you said 1 calorie will raise the temperature of 1 L of water by 1degC.

If you have a handful of raisins, you have 25 calories. That means that it would raise the temperature of water by 25degC for 1 L. However, you have 2 L, so the temperature increase is divided by 2, and it would increase the temperature of 2 L of water by 12.5degC.

The water started at 25degC, plus 12.5degC is 37.5degC and your answer.
Dec 11 2008 5:27PM
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Sean...M
Posts: 2450 - Karma: 14
anyone know how to find the energy required to break bonds?

C2H4F2 is the bond.
Answer is 2990 kJ/mole.

I think i know how to get the first bonds' energy. but not the second part.
Dec 11 2008 7:14PM
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user098123
Posts: 6072 - Karma: 18
There will be a table in the back of your book that will have different deltaH values for each bond. Determine which bonds are breaking, look up the values of those bonds and add them together.
Dec 11 2008 7:20PM
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user098123
Posts: 6072 - Karma: 18
Also I'm not sure what you mean by the "first bond" and "second bond" part...a molecule like C2H4F2 will have multiple bonds.
Dec 11 2008 7:21PM
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Sean...M
Posts: 2450 - Karma: 14
ah yeah your right. do you know how i would determine the energy available from the combustion of 25 g of hydrogen?
Dec 11 2008 7:24PM
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user098123
Posts: 6072 - Karma: 18
Hydrogen is a diatomic element, meaning it exists in the gas phase as H2.

You have 25g of H2, if you combust it you break the H-H bond.

Take your weight, divide by the molar mass of H2, which is 2.02 g/mole. This will give you your answer in moles. Then look in the back of your book and see how much energy it takes to break an H-H bond, that value will be in kCal/mole. So if you have moles, times kCal/mole, you will get an answer in kCal, which is how much heat will be given off by combusting 25g of H2.
Dec 11 2008 7:28PM
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user098123
Posts: 6072 - Karma: 18
Though now that I think about it your teacher may want it more specific, and you would have a reaction of:

2H2 + O2 --> 2H2O

And then you would have to determine the total deltaH of the reaction, bonds broken and bonds formed. Then determine how many moles of H2 you have and multiple that by the number you just calculated (which would be kCal/mole again) and that would give you your answer in kCal's.
Dec 11 2008 7:31PM
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kepler.
Posts: 8761 - Karma: 139
Glrunner...how your Karma isn't at 100000 baffles me. Every homework help thread I see on NS you're always there with the right answer. Plus real life karma!
Dec 11 2008 8:09PM
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user098123
Posts: 6072 - Karma: 18
Haha thanks man, I dunno. I don't really care about karma to be honest. Don't you have to post in different threads, and on pictures and on a blogs and shit to get it high? Somethin, I dunno how it works really haha so I don't bother with it.
Dec 11 2008 8:17PM
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Mr.Capone
Posts: 1227 - Karma: 109
n00b...haha j/k

Good luck wit it. I just finished my finals so I'm gettin drizzy at the moment or else I would pitch in. Chem is the shit by the way. Just wait till you get to organic. It's actually fun. Don't listen to the haters. O'chem is all about 3d visualization and problem solving. Just hope you get a good teacher.

Roiiiiight so that was off topic but whatev...good luck mang!

Oh and GLrunner props for teh uber geniusness...what's yo major?
Dec 11 2008 8:22PM
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user098123
Posts: 6072 - Karma: 18
...chemistry. Hahaha.

And ya, orgo is alot of fun. I work in an orgo lab on campus and it's a pretty good time, usually not even like work. Good times.
Dec 11 2008 8:27PM
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freezed
Posts: 12973 - Karma: 500
there are a lot of chemistry threads on NS recently

some major nerds up in here
Dec 11 2008 8:31PM
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Mr.Capone
Posts: 1227 - Karma: 109
What are tryin to do with it? My housemate is a chem major and homebrewer so he's majoring in chem so he can eventually own a brewery. Gonna go do some business/brewing major in england after undergrad. Anyway, chem is fun so yeahh... I'm a bio major goin pre-med so I have to take all the fun classes. I want nothing to do with P Chem and those other crazy quantum chem classes though. Does NOT look like fun. P Chem raped his ass this quarter haha...

Lab jobs are LEGIT by the way. Spent today shoving sutures into rat's brains to mimic stroke (lttle more complex than that haha) and then removing/analizing rat brains from surgeries we did last week. Best college jobs fo sho!
Dec 11 2008 8:35PM
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kepler.
Posts: 8761 - Karma: 139
Yeah something like that to get it high. I don't care too much either though. I just like giving real life karma.
Dec 11 2008 8:36PM
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user098123
Posts: 6072 - Karma: 18
I want to go to medschool too, but I think I am going to dual major and get a BS degree in Chemistry and Biochemistry. That means I ahve to take all the p.chem and shit like that but oh well, I have a decent gpa and it should look good on my med school application.

If I don't go to medschool I want to get my PhD in some biochemicaltech field and probably work for a pharmaceutical cause I've already spent 2 summers working for Pfizer so I already have a good in.
Dec 11 2008 8:37PM
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freezed
Posts: 12973 - Karma: 500
P chem isn't that bad...Quantum though...I'm studying for my quantum final right now, and it's raping my brain!
Dec 11 2008 8:39PM
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user098123
Posts: 6072 - Karma: 18
Here at Michigan State P.Chem and Quantum Chemistry are the same thing. Not sure what the difference is at other schools.
Dec 11 2008 8:42PM
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COskier
Posts: 1066 - Karma: 131
Easiest shit ever, what the fuck are you guys doing trying to find the energy in the bonds. It says there are 25 kcal in the raisins. 25 kcal will raise 1 liter by 25 degrees and two liters by 12.5 degrees. Your original temp was 25, so 25+12.5=37.5.
Dec 11 2008 8:49PM
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COskier
Posts: 1066 - Karma: 131
^Sorry about that, didn't read the whole thing and now I see its a different question ur talking about. My b.
Dec 11 2008 8:51PM
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Mr.Capone
Posts: 1227 - Karma: 109
There's a guy in our lab who used to work for a pharmaceutical (I think Pfizer actually). They have top of the line EVERYTHING. Apparently the stuff they were surplussing was only a few years old, and we're talking about equipment that is the hundreds of thousands of dollars. It seriously just sits there. I WISH I could go walk though their surplus and just get nice ass shit for our lab (and our budget is pretty damn high too). It's redic how much money they have to throw around. Eventually he quit because he felt like he was selling his soul to the devil (it's pretty dispicable how much they charge for life saving drugs claiming the costs are in R+D....complete bullshit)

Basically what I'm trying to say is it would be really fun to work at a place like that but at the same time I would feel really dirty.

Didn't see you worked for Pfizer....how is it?
Dec 11 2008 8:53PM
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user098123
Posts: 6072 - Karma: 18
Well, first of all ya they have a shitton of money. I could buy anything under $15000 for the lab I worked in without authorization. Another intern I know bought an $800,000 robot for his labs to help him run ELIZA assays. It was pretty awesome, and a great experience.

Getting a job there is pretty hard. Both my parents work for Pfizer so I sorta had an in, but I didn't use them to help me. It just allowed me to know how to apply and stuff like that. Most internships have about 400 applicants per position.

As for the price of R&D and drugs. It actually takes over 1 billion dollars to bring a new drug through all the stages of R&D. That is a 4-7 year process. Then, it has to get through the FDA which is another 5-8 year process. Patents are only good for what, like 16 years? So that means that, since on average it takes like 12-13 years to get through the FDA, the pharmaceutical has to make 1 billion dollars in 3-4 years on the drug (which is a huge accomplishment, if a drug is a blockbuster it is considered having made 1 billion dollars) just to BREAK EVEN and not even turn a profit. After the patent wears out, then any company can market it as a generic and the original patent holder loses their chance at making a good profit on a drug.

It's actually a pretty broken system. In the future companies may not even bother with R&D which is just going to fuck all of us because new drugs won't be coming to market and strains of bacteria will becoming more and more resistant to the current drugs we have. The price of drugs is just about right actually and people who complain about drug costs don't really understand how the system works.

It was an amazing experience (not to mention I made almost $20 an hour) and I can't wait to go back next summer. Hopefully I can grab another position.

Sorry for the essay haha!
Dec 11 2008 9:04PM
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anxju
Posts: 9371 - Karma: 61
you are motherfucking retarded
Dec 11 2008 9:05PM
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Bepo
Posts: 8195 - Karma: 17
none, i ate the raisins. mmmmmmmmmmmmmmmmmmm
Dec 11 2008 9:08PM
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freezed
Posts: 12973 - Karma: 500
(I'm at UBC), my P Chem class deals with purely classical definitions...statistical mechanics/thermo.
Dec 11 2008 9:36PM
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user098123
Posts: 6072 - Karma: 18
Ah I see, ya our third year consists of Quantum Chem and then just Thermo.
Dec 11 2008 9:38PM
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Mr.Capone
Posts: 1227 - Karma: 109
I'm not talking about Americans who complain about the price of drugs like viagra, adderall, skin meds, blah blah blah...I'm talking about multiple thousands of % markup on crucial medications such as TB, HIV anti-retrovirals, etc. I think it's unconscionable for pharmaceuticals to charge 10 grand like they were in the 90's for one course of resistant TB meds. Luckily generics came on the market and now prices are something like under 50 or 100 dollars. I'm just talking from memory and I'm a bit drizzy right now so don't quote me on this.

I believe in high prices for non-crucial drugs. Let them make their profit and foster a healthy company, but for life saving, epidemic ending drugs the companies should take all that money they have and subsidize the costs for the greater good. Honestly, an $800,000 robotic ELIZA robot? For realz? Dude we ran an ELIZA today and it really wasn't THAT bad that it warrented an 800 grand robot to do it for me. It's just stuff like that which pisses me off. Go to a third world country and then try not to be disgusted. I spent the summer in Ethiopia and now our entire culture can sometimes just be really sickening to me.

I do understand your point that the process can often take very long and be very expensive but that's still not much of an excuse for essentially committing murder by making drug prices exclusive to the wealthy. Read some of Paul Farmers books. Went through Harvard med while living/working in Haiti, Founder of Partners in Health, one of the most influential organizations fighting TB (and high drug prices) today. Really impressive stuff.

Sorry for the thread hijack
Dec 11 2008 9:39PM
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user098123
Posts: 6072 - Karma: 18
They still aren't overcharging though. They get almost NO PROFIT from HIV drugs, TB drugs etc. even though they put billions and billions of dollars into them. If they don't charge that price for them, they can't produce them. Especially with TB and HIV drugs where they do put way more money in for very little profit. I garuntee that most pharmaceuticals have never made a dime off of HIV and TB drugs. The price warrants the cost of the research. It will always be that way.

Have you ever seen a sign in a fitting room that says, "We actively stop shoplifters and prosecute them. It's what keeps down our prices." or something to that effect? Well, as soon as a drug companies patents come out, anyone can make their product. It's like shoplifting their idea. They have to charge alot up front in the beginning so they can make money before generics come out. If they didn't do that, then there wouldn't be any money for research at all and no drugs in the first place.


As for the robot, try doing 128 ELIZA's in 3 hours. That's what my friend and I did numerous times throughout the summer on the robot. Not to mention the other couple hundred people or so in the building that used it all the time as well. It warranted the price in manpower by far seeing as how it will be used for years to come.
Dec 11 2008 10:17PM
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seeingstars
Posts: 422 - Karma: 14
the problem is that the government takes away the copyright to the formula for the drugs after like 10 years- at that point anyone can make the drugs- so they have to make all the money to cover the costs and the profit within ten years not.. however long the drug is sold.

It's a failed attempt by the government to make drugs cheaper- all it's doing is giving an incentive to drug companies- not to develop new drugs
Dec 11 2008 10:27PM
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user098123
Posts: 6072 - Karma: 18
Right, that's what I said in my first post. What's the point of spending a billion dollars bringing a drug to market if you only have exclusivity for 3 years and then anyone can make it? There isn't a point. That's why so many drug companies buy out other drug companies that do research. They buy their patents and don't have to pay for the research themselves.

The whole patent system is very broken in general.
Dec 11 2008 10:31PM
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Mr.Capone
Posts: 1227 - Karma: 109
All right so the robot is tight as hell. 128 in 3 hrs? Damn son.


Dec 11 2008 10:51PM
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