Posts tagged "Chemistry"

Analytical Chemistry Questions (2)?

Question by NiNi: Analytical Chemistry Questions (2)?
I just need someone to check my work on some of them. The others I’m lost on. Thanks.

(4.) A method to measure soluble organic C (MM 12.01 g/mol) in seawater includes oxidation of the organic materials to CO2 (MM 44.01 g/mol) with K2S2O8 (MM 270.34 g/mol) followed by gravimetric determination of the CO2 trapped by a column of NaOH-coated abestos. A water sample weighing 6.2340g produced 2.3783g of CO2. Express the concentration of carbon in seawater in ppm.

2.3783 g CO2 ( 1 mol CO2/44.01 g CO2) (1 mol C/1 mol CO2) (12.01 g C/ 1 mol C) = .6490 g C

.6490 g C/ 6.2340 g water= .1041

.1040 g C (1000mg/g) (1/ 1L)= 104.1 ppm
———————————————————————–
(5.) Long ago, a worman at a dye factory fell into a vat of hot piranha solution (concentrate sulfuric (MM 98.08 g/mol) and nitric (MM 63.02 g/mol) acids). He dissolved completely, but no one witnessed him fall in. In order to collect his insurance money, his wife, a chemist, needed to prove that he actually fell in. His wife knew that the human body contained about 6.3 ppt (mg/g) of phosphorus ( MM 30.97 g/mol), and that the piranha solution should contain very little (if any) phosphorus naturally. If her husband weighed 85.0 kg and the vat contained 8.00kL of piranha solution, what quantity of phosphorus per 100mL of vat solution would prove the chemist’s husband fell into the vat and get her the insurance money?

I HAVE NO IDEA HOW TO DO THIS ONE…
——————————————————————————–
(8.) Determine the analytical molar concentration of O (MM 16.00 g/mol) in a solution of ferrous ammonium sulfate hexhydrate: FeSO4(NH4)2SO4 6H2O (MM 392.21 g/mol) if the soln was prepared by dissolving 0.4695g of solid ferrous ammonium sulfate hexahydrate in enough DI water to make 750.00mL of soln.

.4695 g x/ .750L ( 1mol x/ 392.21 g x) (14 mol O/ 1 mol x) = .02235 M O
——————————————————————-
(9.) Suppose the actual sodium chloride content of the sample is 2.621e-5M. Assuming that this sample cane be considered a dilute aqueous solution, does this experimental data differ sig at 98%?

Trial Conc NaCL,ppm
1 1.501
2 1.567
3 1.497
4 1.503
5 1.512
6 1.498

Number 2 is an outlier.

Best answer:

Answer by Steve O
this looks good, even though it is hard to believe that “6.2340g produced 2.3783g of CO2″:
2.3783 g CO2 ( 1 mol CO2/44.01 g CO2) (1 mol C/1 mol CO2) (12.01 g C/ 1 mol C) = .6490 g C

.6490 g C/ 6.2340 g water= .1041 grams of carbon / gram of sea water

but the following needed another factor of X’s 1000 in the 1000g/1L:
.1040 g C (1000mg/g) (1/ 1L)= 104.1 ppm

@ 0.1041 g C per gram water X 1,000,000 grams of water =
104,100 ppm

are you sure of the “2.3783g of CO2″
=============================================

(5.) 6.3 ppthousand, (grams of P per 1000 grams of human), of phosphorus
her husband weighed 85.0 kg
and the vat contained 8.00kL of piranha solution,
what quantity of phosphorus per 100mL of vat solution

find phosphorus:
85,000 g human @ 6.3 g Phos / 1000 g human = 535.5 g Phosphorus

535.5 g Phosphorus / 8000 litres = 0.06694 grams / litre

0.06694 grams / litre = 0.006694 grams of P / 100 ml

the parts per thousand had only two sigfigs, perhaps they would wish you to round off to 0.0067 grams of P / 100 ml solution
============================================

yes it is a strange question:
(8.) Determine the analytical molar concentration of O (MM 16.00 g/mol) in a solution of ferrous ammonium sulfate hexhydrate: FeSO4(NH4)2SO4 6H2O (MM 392.21 g/mol) if the soln was prepared by dissolving 0.4695g of solid ferrous ammonium sulfate hexahydrate in enough DI water to make 750.00mL of soln.

.4695 g x/ .750L ( 1mol x/ 392.21 g x) (14 mol O/ 1 mol x) = .02235 M O

one thought comes to mind, since it would be the total “O” that could be found if a sample was analyzed,… we likely should include the “O” in the liter of solution which is essentially all H2O:
1000 ml @ 1.00 g/ml @ 1 mole / 18.02 g/mole H2O = 55.4939 Molar

55.4939 Molar plus 0.02235 M = 55.5162

your possible answer = 55.52 Molar “O”
===========================================

9) 2.621e-5M @ 58.44 g/mol = 1.532 e-3 g/litre = 1.532 mg / litre

3 1.497
6 1.498
1 1.501
4 1.503
5 1.512

2 1.567

Number 2 is an outlier.

Add your own answer in the comments!

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EO | A Song We Made For A Chemistry Project

The first song in our upcoming album titled 21st Century Educational Raps. © ExplodingOvens Records (Download Link Coming Soon) LYRICS: Asbestos (Jake Hattis) Mine to explain is asbestos And it’s very strong But to use it Is very wrong It’s a mineral fiber And to get it you have to mine When used in the economy It really shined It’s impervious to flame Let me explain That it was used in building materials The hurt wasn’t to blame Mined since the 1800s And used in many things But if disturbed Tiny fibers spread their wings And to the lungs These fibers cling The result is a disease That doesn’t make you sing …Cancer (Be more precise with what type of cancer) Mhmm…lung cancer… Nitromethane (Omar Alessa) Nitromethane’s the name Don’t wanna get it in your brain For it’s known to be explosive Because it’s used in propane. It’s insane, to obtain You’ll only feel pain After you try and use it to make Yourself go in the fast lane Although it is used as a fuel For drag car races NASA likes to make it A source to use for their launches It’s also used as a stabilizer For chlorinated solvents And it is used in dry cleaning And also for degreasing Terrorists use it to To make bombs go BOOM Vin Diesel uses it To make cars go VROOM So don’t you dare forget How hazardous it can be It’ll blow you to bits More dangerous than TNT So don’t become a fool Don’t act like a tool Because it’s uncool To put it in your car as a fuel It’s like pre-school! Make it a rule To not buy a module Or …
Video Rating: 5 / 5

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The Lyrical Professors | A Song We Made For A Chemistry Project

The first song to our future album “21st Century Educational Raps.” © ExplodingOvens Records 2011 LYRICS: Asbestos (Jake Hattis) Mine to explain is asbestos And it’s very strong But to use it Is very wrong It’s a mineral fiber And to get it you have to mine When used in the economy It really shined It’s impervious to flame Let me explain That it was used in building materials The hurt wasn’t to blame Mined since the 1800s And used in many things But if disturbed Tiny fibers spread their wings And to the lungs These fibers cling The result is a disease That doesn’t make you sing …Cancer (Be more precise with what type of cancer) Mhmm…lung cancer… Nitromethane (Omar Alessa) Nitromethane’s the name Don’t wanna get it in your brain For it’s known to be explosive Because it’s used in propane. It’s insane, to obtain You’ll only feel pain After you try and use it to make Yourself go in the fast lane Although it is used as a fuel For drag car races NASA likes to make it A source to use for their launches It’s also used as a stabilizer For chlorinated solvents And it is used in dry cleaning And also for degreasing Terrorists use it to To make bombs go BOOM Vin Diesel uses it To make cars go VROOM So don’t you dare forget How hazardous it can be It’ll blow you to bits More dangerous than TNT So don’t become a fool Don’t act like a tool Because it’s uncool To put it in your car as a fuel It’s like pre-school! Make it a rule To not buy a module Or you’ll have to ride to school …

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Help with chemistry pre-ap?

by Ken Lund

Question by *Mairah*: Help with chemistry pre-ap?
2. assuming a half-life of 1599 years, how many years will be needed for the decay of 15/16 of a given amount of radium-226? what is the original and final amount?

3. the half-life of radon-222 is 3.824 days. after what time will one-fourth of a given amount of radon remain? i already got the answer..i just need to know the original amount.

4. how is nuclear stability related to the neutron-proton ratio?

5. is 9/3 Li a stable isotope of lithium? explain.

6 .what is required to shield alpha particles and why are these materials effective?

7. A. what is the average exposure of people living in the united states to environmental background radiation?

B. how does this relate to the maximum permissible dose?

Best answer:

Answer by Etienne de Quercy
use perhaps the Riemann’s dzeta function

What do you think? Answer below!

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ACS Heroes of Chemistry 2011

Video celebrating the work of the 2011 ACS Heroes of Chemistry. Dr. George Trainor, formerly with DuPont, was recognized for his chemical innovation in dye terminator DNA sequencing. Dr.s Andy Barker and Keith Gibson, both formerly with AstraZeneca, were recognized for the discovery and development of Iressa, a tyrosine kinase inhibitor for the treatment of select types of lung cancer.
Video Rating: 5 / 5

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How do I test for the following pollutants in a lab (Environmental Chemistry)?

by WSDOT

Question by beltlessbob1: How do I test for the following pollutants in a lab (Environmental Chemistry)?
Sulfer Dioxide (SO2)
Carbon Monoxide (CO)
Nitrogen Dioxide (NO2)
Ozone (O3)
Lead and Heavy Metals (Pb, Hg, etc.)
Any other that may pertain to this subject.

Thank you.

Best answer:

Answer by Alan Turing
Solids like lead and other heavy metals could obtained by filtering the air particles out of the air. They all form insoluble precipitates with carbonic acid (H2CO3).

Ozone can be determined by its sharp smell if in enough concentrations. In Central Florida it is a common smell in the air after a thunder and lightening storm.

NO2 is a brown gas that is easily seen in concentrations in the distant near the horizon.

SO2 can be determined by bubbling the air though water and testing for increased acidity. It also has a sulfur like smell in concentrations.

CO is the most difficult gas. It is colorless and odorless. It will any animal life that is forced to breath it. There are CO detectors that can be bought. I had one in the cabin of my boat which had an inboard gasoline engine.

All of these gases can be detected by a gas chromatograph in a lab.

Add your own answer in the comments!

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Cannabinoid Chemistry: THC CBD THCV CBC

Cannabinoid Chemistry: Tetrahydrocannabinol Cannabidiol Tetrahydrocannabivarin Cannabichromene Buy DVD: www.amazon.com IMDB: www.imdb.com THC Ministry: www.thc-ministry.net Wikipedia: Phytocannabinoids: en.wikipedia.org THC: en.wikipedia.org CBD: en.wikipedia.org…

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Easy and kind of fun? Chemistry homework help?

Question by мѕ. ѕαrсαѕм ¤¤¤¤¤¤: Easy and kind of fun? Chemistry homework help?
I have this fun little extra credit worksheet I need help with. The worksheet works like this- you’re given clues like “The 43rd President’s middle initial”. The 43rd’s president’s name was George W. Bush. The middle initial is W, which is the element symbol for Tungsten on the periodic table. So, I’d write down Tungsten as the answer. Another example is the clue “Cow’s favorite response”. Cow’s say moo. So, I’d right down Molybdenum as the answer because its element symbol is “Mo” on the periodic table.

I need help with these clues if you have the time. Thanks.

1.) Sound a horse makes
2.) Enthalpy
3.) A nurse
4.) Pressure
5.) Entropy
6.) Good ___, see you later
7.) Volumn
8.) e.g. Everest
9.) Cajun country
10.) A serious lung disease

Thanks for any help you guys can give me. I really need the extra credit.

Best answer:

Answer by BABY678
1) neigh Na Sodium
2?
3 Rn Radon
4. Barometer Ba- barium
6?
7?
8. Mount Mt Meitnerium
9. ?
10. bronchitis Br Bromine

Add your own answer in the comments!

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some question on diving and chemistry?

by Pulmonary Pathology

Question by PaLi: some question on diving and chemistry?
these are basically related questions…

1-why is there risk of lung lesion if a diver holds his breath while his swimming to surface (that means his going up so the pressure is reducing)?

2- what does a diver have to do to conserve the same respiratory volume as when his on the surface?

3-what will be the result of this action on the concentration of air his the diver’s lungs?

Best answer:

Answer by calchemist3
1 – At depth the pressure is much greater than it is at the surface, so if you look at your ideal gas equation (PV=nRT) you’ll see that (given conservation of n, R, T) the air that the diver breathes in at depth (high pressure) will have a much greater volume on the surface. PV=P’V’ –> (P/P’)V=V’ as P’<

>V. Now think about a balloon. If the air inside of the balloon increases in volume rapidly what happens?? Yep… POP!!! Really don’t want that to happen to you lungs.

Now think about the rest of the problems along these lines… think about what’s being held constant and what’s changing… should be pretty straight forward. Oh, and for part 3 here’s a hint: concentration can be expressed in n/V.

Give your answer to this question below!

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Chemistry on the Web: How Can we Crowdsource Chemistry to Solve Important Problems?

Google Tech Talk April 6, 2010 ABSTRACT Presented by Dr Matthew Todd, School of Chemistry, University of Sydney. Open Science: how can we crowdsource chemistry to solve important problems? Science shaped itself in the founding days of learned societies: individuals or teams competed, in secret, with paper-based communication in subscription journals. Why are we all still doing science like this? The internet has had a major impact in our sharing of data by traditional means, but it has not yet radically changed the way we actually perform science. My lab is involved in a new project a government/WHO-funded research project that is completely open, where we are trying to solve a serious problem in public health through basic research in organic chemistry. The project involves a wonder drug used to treat a tropical disease but we need to improve it, and fast: www.nature.com With an eye on the bigger issue, we propose open methods can allow science to happen faster than traditional means, but we do not yet have the tools to make this happen. This talk is about hard science and soft human nature. It is also an appeal for decent tools scientists need to collaborate properly. The over-riding requirement: low barrier to entry.
Video Rating: 4 / 5

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please see my question, its a marathon problem for chemistry and i really need help. im not sure what to do.?

Question by beautifulbaby<3: please see my question, its a marathon problem for chemistry and i really need help. im not sure what to do.?
Use the following information to identify element A and compound B, then answer questions a and b.
An empty glass container has a mass of 658.572g. It has a mass of 659.452g after it had been filled with nitrogen gas at a pressure of 790. torr. and a temperature of 15˚C. When the container is evacuated and refilled with a certain element (A) at a pressure of 745 torr and a temperature of 26˚C, it has a mass of 660.59g.
Compound B, a gaseous organic compound that consists of 85.6% carbon and 14.4% hydrogen by mass, is placed in a stainless steel vessel (10.68L) with excess oxygen gas. The vessel is placed in a constant –temperature bath at 22˚C. The pressure in the vessel is 11.98atm. In the bottom of the vessel is a container that is packed with Ascarite and a desiccant. Ascarite is asbestos impregnated with sodium hydroxide; it quantitatively absorbs carbon dioxide:
2NaOH(s) + CO2 (g) → Na2CO3(s) + H2O(l)
The desiccant is anhydrous magnesium perchlorate, which quantitatively absorbs the water produced by the combustion reaction as well as the water produced by the above reaction. Neither the Ascarite nor the desiccant reacts with compound B or oxygen. The total mass of the container with the Ascarite and the desiccant is 765.3g.
The combustion reaction of compound B is initiated by a spark. The pressure immediately rises, then begins to decrease, and finally reaches a steady value of 6.02atm. The stainless steel vessel is carefully opened, and the mass of the container inside the vessel is found to be 846.7g.
A and B react quantitatively in a 1:1 mole ratio to form one mole of the single product, gas C.

A.How many grams of C will be produced if 10.0L of A and 8.60L of L of B (each at STP) are reacted by opening a stopcock connecting the two samples?
B.What will the total pressure in the system?

Best answer:

Answer by m w
someone else asked this very same question…. what on earth are your teachers doing to you?

read my answer here…

http://answers.yahoo.com/question/index;_ylt=AhusKfc1.usBfr0_5sQ_0Rnty6IX;_ylv=3?qid=20100212095255AAPpGye&show=7#profile-info-LzqtOG2Taa

now… my answer to part 4 may be different than your instructors. he may be thinking only the Cl2 is in vapor phase. And the clausius clapeyron equation is an approximation.

*****************
*****************
questions?

Add your own answer in the comments!

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Chemistry / Chemical Reactions Related to Lung Cancer?

by the|G|™

Question by Nolly: Chemistry / Chemical Reactions Related to Lung Cancer?
What are some ways chemical reactions or chemistry effects, or creates lung cancer?
I need at least three different legit sources (no WiKi) that discuss the topic.
Thanks a ton!

Best answer:

Answer by Spreedog
From the Journal of the National Cancer Institute.

http://www.ncbi.nlm.nih.gov/pubmed/10413421

“Among the multiple components of tobacco smoke, 20 carcinogens convincingly cause lung tumors in laboratory animals or humans and are, therefore, likely to be involved in lung cancer induction. Of these, polycyclic aromatic hydrocarbons and the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-bu… are likely to play major roles. This review focuses on carcinogens in tobacco smoke as a means of simplifying and clarifying the relevant information that provides a mechanistic framework linking nicotine addiction with lung cancer through exposure to such compounds. Included is a discussion of the mechanisms by which tobacco smoke carcinogens interact with DNA and cause genetic changes–mechanisms that are reasonably well understood–and the less well defined relationship between exposure to specific tobacco smoke carcinogens and mutations in oncogenes and tumor suppressor genes.”

Also from http://jnci.oxfordjournals.org/cgi/content/short/91/14/1194

This article from the Univ. of Pennsylvania talks about “oxidative stress” caused by carcinogens in tobacco smoke.

http://living.oneindia.in/health/disorders-and-ailments/2008/tobacco-carcinogens-cause-lung-cancer-300508.html

If you missed the key points here -
Chemical interaction with DNA causing mutations is one mechanism
Mutations in oncogenes and tumor suppressor genes are other biochemical considerations. You might access entire articles for more detailed biochemical information.

Added note – For whatever reason, the sites do not come up with the links I transferred to this answer. Simply do a Google search with this “tobacco carcinogens and lung cancer” and you will get these sites for your study. Good Luck.

What do you think? Answer below!

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CHEMISTRY PROBLEM VERY HARD, I NEED SOME HELP?

Question by Inna: CHEMISTRY PROBLEM VERY HARD, I NEED SOME HELP?
An empty glass container has a mass of 658.572 grams. It has a mass of 659.452 grams after it has been filled with N2 gas at a pressure of 790 torr and a temperature of 15oC. When the container is evacuated and re-filled with an unknown element (element A) at a pressure of 745 torr and a temperature of 26oC, it has a mass of 660.59 grams.
Compound B, a gaseous organic compound that consists of 85.6% carbon and 14.4% hydrogen by mass, is placed in a stainless steel vessel (10.68 L) with excess oxygen gas. The vessel is placed in a constant-temperature bath at 22oC. The pressure in the vessel is 11.98 atm. In the bottom of the vessel is a container that is packed with ascarite and a desiccant. Ascarite is asbestos impregnated with sodium hydroxide; it is used to absorb carbon dioxide via the reaction:
2NaOH(s) + CO2(g) → Na2CO3(s) + H2O(l)
The desiccant is magnesium perchlorate, which absorbs the water produced by the combustion reaction as well as the water produced via the reaction above. Neither the ascarite nor the desiccant reacts with compound B or oxygen. The total mass of the container with the ascarite and desiccant is 765.3 grams.
The combustion reaction of compound B is initiated by a spark. The pressure immediately rises, then begins to decrease, and finally reaches a steady value of 6.02 atm. The stainless steel vessel is carefully opened and the mass of the container inside the vessel is found to be 846.7 grams.
Element A and compound B react in a 1:1 mole ratio to form one mole of gas C.

Using the information above, answer the following four questions:
1)What is the identity of element A?
2)What is the identity of compound B?
3)How many grams of C will be produced if 10.0 L of A and 8.60 L of B (each at STP) are reacted by opening a stopcock connecting the two samples?
4)What will be the total pressure in the system from a part 3?

Some helpful hints:
A)Draw the setup described for compound B to make sure you understand what chemicals are in which container.
B)You must identify A and B (questions 1 and 2) before you can answer questions 3 and 4.
C)The problem involves concepts and uses the same calculations that you’ve been solving in chapters 2-5. All the equations and chemistry you need to know to solve this are in those chapters.

Best answer:

Answer by Matthew
This question is too long. I will answer it in detail if you send me a paypal for at least $ 5

Add your own answer in the comments!

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Chemistry- Physical and chemical properties?

Question by BreeBreeBRAN™: Chemistry- Physical and chemical properties?
I don’t get these.
We had to read certain pages of our science text book and do this homework.
But the book said nothing about these questions.
Help?

1: Can you always tell what a material is by looking at it? Give an example.
2: What type of properties describe how one material acts on other materials?
3: What type of properties describe how a substance acts under various conditions?
4: How do scientists use their knowledge of physical and chemical properties?
5: How do scientists identify the chemical properties of materials?
6: If you had a piece of asbestos paper and a piece of plain paper, how could you tell which was which?
7: If you had a jar of alcohol and a jar of water, How could you tell which is which?
8: Can two items of different size have the same physical properties? Give an example.
9: When testing for the chemical properties of a substance? Will one test always be enough to identify that material?
10: Can a material have many different chemical properties?

Best answer:

Answer by lizzle sizzle
The book would have said something about these. I can already answer the first one in my head. Don’t be lazy and do your OWN homework by either reading through the book again or searching the internet. If you still have trouble, go and ask your teacher, they’ll be glad to help you that’s what they’re for.

Give your answer to this question below!

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Asbestos and Other Fibrous Materials: Mineralogy, Crystal Chemistry, and Health Effects Reviews

Asbestos and Other Fibrous Materials: Mineralogy, Crystal Chemistry, and Health Effects

This comprehensive sourcebook describes the chemical, physical, and mineralogical aspects of fibrous inorganic materials, both synthetic and naturally occurring. A general description of the fibrous state, the range of compounds that can adopt this form, and an overview of the characteristics unique to such materials form the backbone of the book . The authors also assess the application and use of asbestos and other fibrous materials in industry and evaluate their potential as health hazards

List Price: $ 210.00

Price: $ 183.10

Related And Asbestos Products

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