Chemistry

Double header 1. What is the black oily greasy muck that clings to every surface of my bike after a few kilometres of London riding? I end up cleaning my chain every day now - I do 50km through pretty grimy London every day and by the end of that all oiled surfaces are covered in thick cloying black gunk. It is non-water soluble and has a fair amount of plain micro-grit in it - but what else? Even the non-lubricated surfaces are covered to a lesser extent. Grit, soot, remains of my lube...and what else? 2. I have tried the commercial chain cleaning solutions - and they work but are pricey and smell frightful. What could I try as a safe, reasonable non-toxic,…

I didn't want to make a thread just for this simple question, but... does n signify an integer, and if so ,what for? Thanks in advance.

Hi guys, Can anyone explain to me please how would I use solubility curves in separating a mixture of salt and gravel to prepare pure salt crystals? I initially assumed to add water to the mixture and stir until all the salt had dissolved and then separate the mixture using a sive. Then I would slowly heat the brine mixture until all the water had evaporated producing the salt crystals. But I dont know if this is the best method? Would the salt be considered pure crystal? And more importantly how would I incorporate the solubility curve in this process? Thanks in advance.

This is a dumb question! however I have been told on this forum that units are just that "units" and they have no meaning. But I have read how science in the past have had many accidents because of SI Unit Conversions, or units mistaken in general.. I don't see how on earth without math that units could be applied and measured. Either I am dumb and retarded or someone is pulling my leg.

Hello new around here.. I work at a chiller plant where we have over 30000 tons of cooling capacity for the university. My boss wants to remove the rust from the inside of our steel evaporator shells which I feel is just busy work. And may also speed up further corrosion. Does steel rust faster when its clean? Or does a layer of rust already formed, slow down further corrosion compared to raw steel? Thanks!

Hi. Does anybody know what CaCO3+Zn+heat will produce? Thanks a lot for any help!

Hello! Do you know some application for generating chemical formulas? I mean something like- enter quantities of atoms, and program should show the all *) existing and plausible chemical formulas possible to make from them. f.e. If I enter C=1,O=2, it will show CO2 (O=C=O), If I enter C=3,H=8,O=1, it will show CH3-HCOH-CH3 but also C3H7OH *) in reasonable amount..

What does "C and I" mean? source: http://www.vikingchemical.com/marketindustrial.php

There are various sites that sell tiny amounts of radioactive material purely for the purpose of testing gieger counters and I just wanted to make sure that should the container be broken, would I be in any sort of danger? What if I touch it with my hands? For example: I don't want to bring it back from the US and have any gieger counters going nuts at the airport...

Does radioactive decay cause an element to change to another element? Okay let's use Uranium as an example of alpha radiation. What characterizes alpha radiation is the emission of helium nuclei from the element. A helium nucleus contains 2 protons and 2 neutrons. This means the atom is spitting out protons, so does that mean the element changes due to the proton loss. After all that is what makes an element unique-- its proton count. So my question is...would the Uranium atom change into a different element? Thanks.

Where can i buy chemicals? (apart from ebay)

Hi, I'm a British student in the first semester of my BSc in Chemsitry here at Xiamen University in China. This question is aimed at people literate in Chinese. In Chemistry in the English language so far as I'm aware we don't have this or we just describe it in words. What do these characters mean that appear after state variables? (There are a lot, here I am only showing a few) Is there a website/book with the translations? I have looked in Eng-Chi dictionaries of chemistry and they dont show it. Eg. p=p实-p内 Eg. p总V总=nRT Eg. (delta)U=U生-U反 thanks in advance, 谢谢

Hi, i'm new to this site, and i'm sorry if i'm not posting this in the correct forum. I want to measure fat content of a milk solution. And I want to measure it with any equipment and get a digital input to a computer. Are there any sensors for that? If not how can i make one? thanks.

Would anybody be as kind to provide the chemical compositon of the alberta oil sands tailing ponds compostion

Hello everyone, don't worry I'm not looking to kill someone haha I've been watching a TV series called Fring, it's great you should give it a try, Anwyay in some of the episodes the criminals use poisions or toxins which are colourless, odorless and that travel through air, if you breath it in you die. I wanted to ask if poisons like this really exist? In one of the episodes he has some clear white liquid in a sealed glass bottle, he puts it in the air vent and takes the lid off so the fumes travel through the vent system and kill everyone. Just wondering if you could tell me the names of anything like this that actually exists. Strictly for research purposes …

That is..could you subject caffeine to a vaporized state, and then inhale it, in order to hasten its effects on you, rather than wait fo ti took take affect via liquid?

An endothermic reaction is required to break a chemical bond right? When a bond is formed, the reaction is exothermic. So... why does splitting an atom yield an highly exothermic reaction if there are no new bonds forming? ~ee

Coming from a confused introductory chemistry student... My problem began while I was reading over the chapter on aqueous reactions. Rather than go into chronological detail about my confusion, I'll just ask the more fundamental questions first to see if there's a root misconception involved. 1) Okay, so when a compound is said to be molecular, it contains covalent bonds. (so, "covalent" and "molecular" are, in a sense, interchangeable) Correct? 2) Ionization vs dissociation: An ionic electrolyte dissociates in aqueous solution, while a molecular electrolyte is said to ionize. Is this right? I'm not sure if the terms are somewhat interchangeable or if they're …

Hi, I am doing a school project on the rock cycle. I hope this is the right forum to post this in! Im trying to make a demonstration of how metamorphic rocks are made. I have some shiny glittery brown powder (this is suppose to represent the dirt). My dad made me a presser using a box, a lid and c-clamps. I moisten the brown powder a bit, then put the brown powder into the presser and put the lid on top then use the c-clamps the apply pressure. After half an hour I take it out and it is a rock, which is good. When I break open the rock though to test how hard it is, its always kind of chalky on the inside. All of the shine and glitter is gone. But when I look at metamorp…

If a coordination compound is given, how can you determine its proper shape from its formula? I wanna know the process.

How could one explain the difference in H2O2 stability in acid and basic solutions using Le Chatelier's principle?

I am studying thermochemistry and trying to find the complete Born-Haber cycle for the reaction of H2SO4(aq) + Mg(s) to MgSO4(aq) + H2(g). Mg(s) + H2SO4(aq) ∆Hf[Mg(s)] Mg(l) + H2SO4(aq) ∆Hv[Mg(l)] Mg(g) + H2SO4(aq) 2 ∆Hb[O−H] Mg(g) + 2 H• + SO42- −∆Hb[H−H] H2(g) + Mg(g) + SO42- −∆Hie1[Mg(g)] H2(g) + Mg(g)+ + e- + SO42- −∆Hie2[Mg(g)] H2(g) + Mg(g)2+ + 2 e- + SO42- This is what I came up with. Is this correct, and if so, how can I proceed from here? Any help would be greatly appreciated

What makes beetroot juice a deicer? I read in Fuel Ghoul blog post below that the juice from red beets is being added to rock salt to make a superior pavement deicer, http://roberrific.typepad.com/drunkenmoose/2013/08/best-natural-snow-removal-solution-mixes-beetroot-juice-and-brine.html I'm curious if betanin is the active ingredient? Or is it something else? Betanin is a food colouring agent.

I'm not sure where to post. I'm hoping I'm not breaking any rules by posting here. However, I'm looking for a description/definition of 'plasma' that I can understand. I'm keeping it simple.

Hi, I have a question about the meaning of the nernst potential. say for a reaction A + B = C + D with a caculated nernst potential of -0.5 Does it mean that if I apply a potential of -0.4, the reaction will move forward, i.e. produce C and D?