Carbon Definition and 521 Threads

Hello, I've read that metal film resistors are better than carbon film because they're resistance remains constant even when they heat up from being soldered. And I know they're suppose to be more precise with a 1% variance instead of 5% of the carbon films. I know capacitors go bad - do...

If carbon has the highest melting point of any of our known elements , then how do they melt it , the only thing I could think of is containing it in a magnetic field and maybe using like an electric arc furnace.

I am just wondering if pure carbon and graphite have the same resistivity? Resistivity for pure carbon = 3.5 x 10^-3Ωm:frown:

Hey guys, I'm researching single walled carbon nanotubes and I am trying to find out how much approx. Resistance there is in a pile of ~50nm long metallic SWCNT's piled on top of each other to form a line (think laying gunpowder for a fuse...). I'm perplexed because SWCNT's at the proper size...

Hi, I am doing a research project involving short single walled carbon nano tubes. Has research been done on the material properties of short SWCNT's that have been thermally bonded together? This is theoretically done by taking a few SWCNT's with each one overlapping the other (easiest...

Homework Statement The total mass of C contained in all fossil fuels burned from 1750 to 2000 is estimated as 2.77 x 1014 kg C. The amount of C released as CO2 from agricultural expansion and deforestation during the same period is estimated as 1.31 x 1014 kg C. The concentration of CO2...

An interesting book not so much about global warming but alternate energy and an analysis of the numbers behind it - from a physicist. The book is now available as a free download from http://www.withouthotair.com/ Ignore the physicist grade graphic design of the website - the book is much...

Homework Statement Calculate what mass of carbon you would need to reduce 15.9g of copper(II) oxide to copper by the reaction: CuO(s) + C(s) \rightarrow Cu(s) + CO(s) Homework Equations n = m / ar (number of moles = mass / relative atomic mass) If you know any more, it would be really...

Hi, I am doing an experiment involving activated carbon and I need to know if activated carbon has a high level of conductivity. I've searched the internet but without results. in addition, if the Active carbon can be made to be or is conductive, does the immense internal surface area still...

Hi friends, I've calculated the transmission spectrum of ideal carbon nanotubes for various applied voltages on them. I obtained the transmission spectra shown below for various bias voltages. However, I could not interpret why the transmission spectra changes so much with the bias voltage...

http://www.ucar.edu/news/releases/2009/arctic2k.jsp The associated albedo flip will amplify the warming.

I am not sure how to approach this problem. If you have a carbon steel pipe that is being heated on one end at a constant temperature of 1500C. Can you figure out how much distance in pipe will it require before it cools to 790C? The thermal conductivity of Carbon steel is 54 W/mk. Another...

I am doing research into an internal corrosion/erosion problem on a methanol pipework processing line. The pipe is made out of carbon steel and I am looking at replacing it with a duplex steel like Inconel 625 or HASTELLOY. Does anyone know how I could go about working out the costs involved so...

I have been interested in atmospheric CO2 variance on geological time scales for sometime. There are multiple paradoxes associated with trying to explain what could cause massive cyclic rapid CO2 changes in the atmosphere. There appears to be multiple fundamental errors in terms of what is the...

Homework Statement A compound contains only carbon, hydrogen, nitrogen, and oxygen. Combustion of 0.157 g of the compound produced 0.213 g CO2 and 0.0310 g H2O. In another experiment, it is found that 0.103 g of the compound produces 0.0230 g NH3. What is the empirical formula of the compound...

Homework Statement A carbon sample taken from the bone of a saber tooth tiger emits 1 beta emission a minute. A carbon sample of the same size taken from a frest piece of bone emits 16 beta emissions a minute. How long ago did the saber tooth tiger live? How can i do this? Homework...

I was reading a chemistry book and found something that doesn't seem right to me. Read the underlined part. http://img139.imageshack.us/img139/6192/carbonz.jpg Isn't that incorrect? Doesn't it have two unpaired valence electrons instead of four?

Anyone know a good source to learn more about them. Recently I was watching a video at www.ted.com and a speaker purposed interesting concepts about single layer carbon nanotubes. Questions I have: Acceleration of particles(The speaker said something about accelerating particles using...

When the hydrogens/protons are removed, leaving C-, can someone please tell me what and why the SP orbitals of these two carbons are? http://img30.imageshack.us/img30/5333/40529044.jpg Thanks.

The on on the left w/ the red arrow pointing to it: http://img198.imageshack.us/img198/5062/92513846.jpg

i am trying to understand what a pseudochiral carbon is? please help thanks in advance

Homework Statement How many sp3-hybridized carbon atoms does tamoxifen possess? This is tamoxifen: http://en.wikipedia.org/wiki/File:Tamoxifen_Structural_Formulae.png2. The attempt at a solution Are all carbons sp3-hybridized? Does the hybridization of carbon vary, depending on the bonds (ie...

Will carbon powder dissolve (ionize) in sulfamic acid? If so, what ionic state?

If direct current is applied to activated carbon, will it be drawn to the cathode?

Hi, first time poster. Quick question: Why is the bond energy for a bond that contains a more highly substituted (tertiary) carbon weaker than the bond energy of a bond that contains a less substituted (primary) carbon? Let me clarify with an example. Say Bond A is a single bond between a...

I have two questions about carbon steel. How does the carbon content of steel effect the rate of corrosion? Apart from providing strength to the steel, how does carbon effect the properties of steel?

http://www.rsc.org/chemistryworld/News/2006/November/15110602.asp Carbon nanotubes are no longer the proud boast of 21st century materials scientists. It appears their discovery was unwittingly pre-empted by mediaeval Muslim sword-smiths whose tough Damascus blades taught the Crusaders the...

Does anybody know the acoustic properties of carbon fiber. I've used google extensively but I've had no success. Is there a well known reference book within the materials engineering realm that gives the sound absorption coefficient (also known as the Noise Reduction Coefficient (NRC)) of varius...

If diamonds are made of carbon? and coal is made out carbon, why are diamonds transparent and coal is not transparent?

Homework Statement Calculate the percent carbon in an iron-carbon alloy that will give no volume change when liquid transforms to austenite plus graphite during solidification. Homework Equations Density of liquid = 7.0 g/cc Density of austenite = 7.69 g/cc Density of graphite = 1.5...

Carbon dating like techniques...Reliable or not? Hello, As I have learned Carbon, uranium & other elements of radioactive nature are now used for dating how old an object is... I am wondering how does this technique work exactly & how reliable it is... The only samples which are the basis...

Hi guys, i have been searching for ages to get figures for the proof or yield strength of EN1A steel, which is now known as 220M07 as per BS970. I have managed to obtain the Tensile strength, but would anyboday please be able to help point me in the right direction to data for the yield or...

hi, i can't find any standard defining design of unfired pressure vessels made from carbon fiber, kevlar, fiberglass or similar high tensile strength materials*. do standards like these even exist, since these materials are relatively new? * you know any more similarly competitive materials...

Homework Statement Natural carbon consists of two different isotopes (excluding 14C, which is present in only trace amounts). The isotopes have different masses, which is due to different numbers of neutrons in the nucleus; however, the number of protons in the same, and subsequently the...

Hello, I am searching for the properties of Carbon Steel S355J0, can anyone help me out? N360

In the reaction of carbon dioxide and water to form carbonic acid, does water act as a lewis base because it donates a pair of electrons to carbon dioxide or does carbon dioxide act as a Bronsted-Lowry base because it accepts a proton from water? Thanks.

When air goes through a carbon filter it separates the carbon and turns it into water and lithium carbonate. Could the lithium carbonate be sold and that money used to buy parts for hydro electricity plants that use the water, or the water be used for drinking as it is already pure?

Hi everyone, i wonder if anyone has an idea how to attack chemically an amorphous carbon film. Is it possible to completely dissociate an amorphous carbon in a chemical solvent? thanks for your help

I've been trying to remove a benzyl protecting group of a phenol and also remove a CBZ protecting group on a secondary amine by standard hydrogenation of the material with 10% Pd on Carbon. My protected molecule is very lipophilic and soluble in DCM. The reason I added methanol was because the...

Homework Statement A typical electromagnetic signal from a communications satellite might have an intensity of 0.9 pW/m2 at the surface of the Earth. Your satellite dish collects the energy of the electromagnetic signal from the satellite; then your dish passes that energy to its central...

Homework Statement The amount of 14C in an old, isolated sample of vegetation is 0.692 that expected from a present day sample with an equivalent carbon content. Calculate the age of the old sample in years. Homework Equations Im fairly sure you use the following equation to solve...

I'm a sophomore Aerospace major, and I'm also a new member to a rocket student group at my university. We are currently involved in a competition with NASA, and they have asked our group to write a Preliminary Design Review. Everything was split up, and I was left with the rocket's airframe...

This is a 3 part question that i have attempted to answer. I'm pretty sure I'm on the right track but i think i made 1 or 2 small mistakes along the way. the question states: The average depth of the ocean is 3.8km and the ocean surface area is 360x10^12 m^2. The average upwelling rate of deep...

The youngest bottom waters in the North Atlantic had a [delta 14 C] value of approx -70o/oo (o/oo being parts per thousand). Bottom waters in the South Pacific have a [delta 14 C] value of -170o/oo, while bottom waters in the North Pacific had a [delta 14 C] value of -230o/oo. a)In the [delta...

My first semester bio course is having us practice writing formal lab reports by doing some research through peer reviewed journals our university has access to and citing it in our paper. however something that keeps coming up in the papers I'm reading is something called "the carbon...

Hi to all i would like to ask is there a way of getting burnt carbon out of the used oil i have tried all i can think of but still can't get it all out is their a bleach or some thing i can use please don't tell me about the old trick with a rope it takes to long Thanks

Hi all,sorry if i commit any mistake while asking this question. Actually right now i am studying FEYNMAN lectures of physics vol.1.ON page 7 of chapter1 it is written and clearly understood that Carbon attracts Oxygen much more than carbon attracts carbon or oxygen atttracts oxygen. But if...

Homework Statement 6CO2 + 6 H2O → C6H12O6 + 6 O2 Now suppose the above reaction is allowed to proceed in both directions, and has reached equilibrium. How would increasing the concentration of oxygen change the concentrations of carbon dioxide and sugar? Homework Equations The Attempt at a...

How to 'produce' martensite and bainite? For what i know, martensite formed by rapid cooling from austenite phase of steel, and slow cooling to form back to it's original state. But in order to form bainite, what's the cooling rate? intermediate between rapid and slow cooling? How rapid and...

Homework Statement In a sample of one litre of carbon dioxide at STP an average of 5 disintegrations C -> N + e + v are observed per minute. Calculate the atomic fraction of C present if the mean lifetime of this nucleus is 8267 years. Homework Equations \tau = \omega-1 = 8267...