Chemical Definition and 1000 Threads

I am reading a chemistry book printed in 1805. The chemical reaction equations are written using the equality symbol = instead of the arrow →, which is used in modern times. Anyway sometimes it is still possible to see the "old fashioned" way...

Correlation of data sets, chemical composition I have roughly 80 test results from different samples, each result set is a list of concentrations of various chemical compounds and proteins obtained through gcms (gas chromatography mass spec) There are over 50 of these compound concentrations...

In a solution of aqua regia (or other acids), if there is a precious metal dissolved, along with other metal ( such as other precious metals or base metals), and you add a powdered metal, you precipitate all the metals lower than it on the reactivity list. If however, you use a chemical...

Hello, I quote from a paper: "...a solution of CuSO4 (1 mM) and NaAsc (2 mM) in 10 mM Tris buffer with 20% DMSO". Does the molarities refer to the 80% volume of the Tris buffer or of the total volume (80% v Tris + 20% v DMSO)? For example, if I want to make 100 mL solution, I have to add...

I'm using a program for calculating chemical reactions, but I'm not a chemist. I will use the results for a different type of calculation. Sorry, this is probably a silly question. As input for the program, I am using a chemical system that someone published. it contains: SO4(2-), Ca2+...

Hello, In my book, we have two equations to find the chemical potential µj=(dF/dNj) T, V and N constants and µj=-kT ln (ζj/Nj) We calculated the potential of a Van der Waals gas using each of these equations, but the result is not the same, i want to understand why ?

We all have been studying chemical bonds, specifically covalent, told to us that it composes of electron sharing between participating atoms. But do we have a scientific evidence that somehow conforms or substantiates this theory? For example, We have evidence to 'believe' in electrons. The...

I read some books which mention about covalent and partially covalent chemical bonds. However, I cannot distinguish between them. Who can help me? Thank you very much!

I'm currently a junior at large state school and am a biochemistry major. I started college in a cell biology major, then realized how much I hated cell biology classes (although I remain fascinated by the chemical reactions and complex chemical structure in living things) and how much I loved...

H2+1/2 O2 ---------> H20 If the equation is multiplied by 2 Will the equilibrium constant change or remain constant ?

Hi all, I'm david from indonesia. Sory for my english. Can you help me to found a chemical that I can use to cleaning printed picture on plastic material? This is for recycling, means in big volume... Thanks before

X + Y + Z -> A + C+ + B- Initial Concentrations Z= 4.1 X 10^-3M, X=2.3 X 10^-1M, Y= 1.2 X 10^-1 M. http://s121.photobucket.com/user/marykaywest420/media/81386cf6-e132-4578-8fb5-1024a2a3f3d5_zpscc804723.jpg.html?sort=3&o=0 3. So my attempt included graphing -R/(R∞-R) vs. time. which produced...

I got a bit of a question that needs answering. See, I'm still not understanding how basic selectivity in organic chemistry works. I'm not looking to know the mechanism or anything. Just one simple thing. I'll give the description given from some textbook first: Homework Statement The...

Hello, Does anyone know of any free software that will allow me to easily create chemical process flow diagrams, that have all the symbols for various components (distillation columns, heat exchangers, etc)? Thank you

I'm currently studying for a test and I'm having problem with this concept: If I have 3 different Equilibrium constants for different reactions like Kc=103, Kc=1 and KC=10-4, which one's forward reaction is most favorable, and which one's reverse reaction is most favorable? Maybe it's the...

Hi guys, As the title suggest I am an student chemical engineer and was wondering if anybody could advise on some good books for the following subjects. I have used spoiler tags to hide the specific areas I will be covering so as to make this post a bit neater. Fluid Mechanics. Process...

Okay let's say we have water, sodium hydroxide and hydrogen chloride. What do you think is going to happen? Do you think the pH will be the same, a little higher, or a little lower? You have this reaction down here: H2O+NaOH+HCl(assuming they are equal)= H2O+OH-+Na+(positive...

Homework Statement Suppose that a large mixing tank initially holds 300 gallons of water in which 50 pounds of salt have been dissolved. Pure water is pumped into the tank at a rate of 3 gal/min, and when the solution is well stirred, it is then pumped out at the same rate. Determine...

In a semiconductor, is the chemical potential of electrons limited to take values only between the valence band maximum and conduction band minimum? Are there circumstances where it can cross these bounds?

For a thermodynamic system there exists a function called entropy S(U,N,V) etc. We then define for instance temperature as: 1/T = ∂S/∂U μ = ∂S/∂N etc. When taking these partial it is understood that we only take the derivative of S wrt the explicit dependece on U,N etc. right? Because...

Hi, I was wondering when you need to write the decomposition of a substance, how do you know if the number is going to be a coefficient or subscript ? Example: 2H2O ===>2H2 + 02 would be the answer But why not 2H2O ==> 2H2 + 2O Knowing that we have 2 moles of O in the beginning...

Homework Statement Good day! I have a question from my chem HW that is stumping me. Although the answer may be simple, it has eluded me for quite a bit. It regards rate laws and constants of reactions. Question is as stated: This reaction was monitored as a function of time: AB --> A + B A...

Hello! What would be the substance, chemical reaction and technique, to have the highest rate of immediate mass change, back and forth, from low to high and back to low again, as many times as needed - using only homemade DIY, non dangerous materials and equipment? My intentions are to...

In an exercise I look at a square lattice and consider a model where the energy band of the electron is half filled and temperature is zero. I am then supposed to explain why a half filled band corresponds to zero chemical potential. For me the most meaningful definition of the chemical...

I am in grade 12 now and I love chemistry and i wanted to be a chemist , but for some reasons i can't go to science school, so instead i decided that to go to engineering school and become a chemical engineer , but then again i had another problem , they only thing available for now is...

Hello, I am concerned for my future. I am interested in Chemical engineering as a subject, but the idea of spending my career making chemicals, being in oil/gas, or even in pharmaceuticals depresses me. I would like to get involved with environmental engineering, or work in sanitation or...

I have seen various treatments of the chemical potential. Basically it all amounted to a definition of it as a quantity maximizing the entropy for systems allowed to exchange particles. Now this quantity has become quite important in some models I am studying for current flow, specifically an...

Hi guys, I just wanted to know a bit about chemical engineering from you guys here.

Are Chemical engineers like applied chemists? Or are they more like mechanical or electrical engineers using their knowledge of chemistry to make things or processes? What tools do chemical engineers use, like tools to measure or tools to build, or both? What kind of things to chemical engineers...

what types of chemical reaction does not have oxdiztion and reduction...

Homework Statement Homework Equationsln[A]=-kt+ln[A]0 The Attempt at a Solution In this equation,is it necessary to have [A] to be the concentration? If there is the mass provided only,can I just subsitute [A]=mass? Sorry for my poor english

Hello, Theoretical physicists assert that quantum mechanic and relativistic world use distinct mathematical models that can not united into one so far. The reason of it, which I do not understand, is the gravity. Once we encompass the gravity in the quantum world (or vice versa), we (maybe)...

Homework Statement Consider a container with two chambers of the same size separated by a fixed membrane in the middle (permeable only to the ideal solute, but not the solvent). One chamber initially contains 1M of solute, and the other contains 0.5M of solute. Write an equation for the...

All of the related work is in the attachment. If you could please help it would be really appreciated. I've asked a bunch of people in my class, and they're confused also. Thanks in advance!

in class, we just learned that the chemical potential was μ=∂G/∂N i'm looking in my book and it says that μ=-T(∂S/∂N) this looks a lot like the partial of heat energy with respect to N. is my interpretation correct? (assuming my interpretation was correct): so qualitatively, the...

Does anyone know of reaction that can generate a a steady source of light? Preferably one easier to activate than burning of magnesium strips(which is too momentary anyway, I'm trying to make a chemical reaction that can eventually power a photoresistor/ light).

So from the first law for a closed system, dU=dQ-dW=dQ-PdV From the second law, dS=dQ/T + Sgenerated (i.e. the entropy generated) Putting expression of dQ from second law into first law, dU=T*dS-T*Sgen-PdV If s and v are constant, dU= -T*Sgen>0 Hence dU<0 This is a...

Homework Statement Hello again! I've googled about chemical binding but couldn't find anything that teaches me about it so I thought I'd ask you guys. I have several elements like NH3 CaO H2 CH4 BaBr2 and need to figure out their chemical bindings. I know that a chemical...

Compose the equation for the reaction of fluoride with potassium nitrate. State the spectator ions. Here is my attempt: K(NO3)2 + F- = N2O6 + KF Or is it K(NO3)2 + NaF = Na(NO3)2 + FK I think the spectator ions are K- and NO3 Any ideas? Thanks

Homework Statement Homework Equations The Attempt at a Solution For this problem, my group is having difficulty figuring out how much Styrene is reacting, since we don't know the molecular weight of polystyrene, we can't find the moles of polystyrene, which would be used to aid in finding the...

1. What is electrochemical equilibrium and what is chemical equilibrium? 2.What are the differences between the two above? 3. The difference between the two i think is electrochemical equilibrium is a state whereby the electrical charge in both compartments are equals. Wherease...

I looked into the field of chemical engineering because of my interests in chemistry and making things, but I saw only things that involved power plant. Do chemical engineers do anything besides building, maintaining and supervising power plants? Thanks.

I have become interested in Biophysics and there are not many programs out there with a BS in Biophysics. I know UCLA and UCSD both have programs but the rest of the UC system unfortunately does not. I will be apply for a TAG (I get guaranteed admissions to some of the UC's if I meet certain...

Hello all, I've got a somewhat mixed concept question from a Chemical Engineering computational methods class. I'm completely lost with this question, as I do not fully understand what it entails. The question (and data) is this: Homework Statement Data Set Given X Y 0.00 -2.17...

So the expression for Gibb's free energy is: dG = -SdT + VdP + μdN, Here, we see that the Gibb's free energy changes with temperature (dT), change in pressure (dP) and change in chemical potential (as a result of change in particle number). My question is: we know chemical potential...

So when osmosis between two solutions (separated by a semipermeable membrane),takes place, the solvent travels from the side where its chemical potential is higher to the side where its chemical potential is lower. However, this results in a difference of levels of fluids across the membrane...

Hi everyone, I'm an a-level student (year 13) doing Physics, Chemistry and Maths. I am struggling of what university subject to apply for...I want to do a subject that is a combination of all three subjects I'm now doing. I like topics that I can go very very deep. I think quantum and...

When I started college, I was a biotechnology major. I found this major be a dumbed down version of molecular and cellular biology, so I decided I wanted to switch out of it and major in biochemistry and molecular biology focusing in biochemistry, the problem was that I had already taken two...

So let`s say that we have a chemical reaction with liquid oxygen and liquid hydrogen, but we`ve got very little hydrogen, and very much oxygen. As we pour these two liquids together they react with on another and create water. However since there was a very much bigger amount of oxygen than...

Homework Statement what is the mass of alum that can be prepared from 1.340g of Al. Homework Equations 2Al+2KOH+4H2SO4+22H2O ---> 3H2 + 2KAl(SO4)2 * 12H2O The Attempt at a Solution given Al is the limiting reagent. Find the moles of Al using n=m/M I find Al moles to be...