Chemistry Definition and 993 Threads

Homework Statement A tank of constant volume V contains air at an initial density pi. Air is discharged isothermally from the tank at a constant volumetric rate of Q (with SI units of m^3/s). Assuming that the discharged air has the same density as that of the air in the tank, find an...

What is the value of optical effective electron mass for tin metal (white tin)? What is the value of mean free path for electron of tin metal? At least give me some websites or papers where I can find it?

I'm getting too different answers for atomic radius of iridium. I've already found 1.34 x 10-8 but all shows different answers. I mean like 1.34, 1.35, 1.36... Are those correct?

I am looking for a free chemistry simulator that allows me to see generally what would happen under certain chemical reactions. I would like it to be relatively simple since I do not know much about chemistry. Any ideas? Btw its for personal use so it does not need to be very accurate. I am not...

I am having difficulty in finding a solution that can etch away tin compounds in my metallic surface. The metallic surface has a composition of palladium, copper, and silver. There is a tin compound deposited on the surface which I would like to etch away or remove. This is on a microscopic...

I am taking the second semester of physical chemsitry (quantum, spectroscopy, and some stat mech). I was wondering if there are any resources outside of the ACS study guide and open course ware. I'd really like some practice tests if possible so I can see what I need to study. Also, any lecture...

Can anyone help me with this ? What does the arrow mean ? Is it cis or trans,the base is small so it should be an E2 elimination with zaitsev product.Though I think it may be due to the beta hydrogen being unavailable,but I do not know whether the arrow means from the upper or lower /cis trans...

Hello everyone, I plan to return back to school in the spring from a small break that i took in order to move out. I was going to school for Engineering Science (associates). I'm basically done with all my general studies and as far as quantitative and natural sciences go I completed Algebra 1...

Hello ! I am preparing for chemistry olympiad,and my friend gave me this exercise in organic chemistry,but he won't tell me what book this is from can anyone help identify what book /problem collection this is ? (It has got some nice problems,at least higher than solomons organic chem) Thanks in...

Regarding a recent article from phys.org , Chilean researchers have conducted a study of an old, metal-rich cluster, NGC 5927. Interesting results are the abundance of many metals, which include sodium, aluminium, iron, oxygen and some heavy metals such as yttrium and zirconium. Thank you.

Hi, I'm a high school chemistry teacher trying to develop a lab experience demonstrating combustion analysis. This is usually something we go through theoretically during discussion of percent composition and empirical formula. I'd like to actually perform one. I was wondering if this could...

I need good books covering the chemistry in the college period. (Not sure if this is the correct name. Just take it to be the period after which one goes to the university.) Any suggestions? In physics we have this book https://www.amazon.com/dp/0321973615/?tag=pfamazon01-20 which covers...

I'm having difficulties figuring out where the new carbon-carbon bond would form. Any help is greatly appreciated. Thank you!

My interest are in robotics/mechatronics, but I've been wondering if a chemistry minor would be useful for a mechanical engineer in other fields in industry.

Homework Statement : 2 Questions, sorry about this if It adds confusion. 1) How do I go about drawing Lewis Structure Diagrams? I've searched the web, but all I can find, even when they say it's a "Lewis structure" diagram is lewis dot diagrams. My teacher wants it in the specific form where...

Homework Statement What product(s) does this reaction produce: Acetone + diethylamine Homework EquationsThe Attempt at a Solution That is what I got, but the answer is N,N-dimethylethanamide. Can someone please explain why?

Homework Statement What is the product of this reaction: p-methylbenzyn + 1,3-butadien? Homework Equations C6H4CH3 + C4H6 The Attempt at a Solution a bicyclic ring is formed?

Homework Statement Homework EquationsThe Attempt at a Solution U is internal energy, but what is u? if its internal energy at a specific state, then why its multiplied by mass? does not makes sense to me...

since specific heat c changes with temperature, but its treated as a constant in the heat formula, so that means that heat formula Q=mc(T2-T1) is just an approximation? correct? I see some texts define heat as Heat, q, is thermal energy transferred from a hotter system to a cooler system that...

Hello, PF in general and specifically the Intro Physics homework forum have been so helpful to me. I have a friend who is taking (introductory?) chemistry in his first year of college, and I'm wanting to recommend one of the forums on here for him to ask questions/get help with the concepts and...

Homework Statement Predict how many electrons will most likely be gained or lost by each element: In this case, Gallium Homework Equations None (that I know of) The Attempt at a Solution [/B] I know that Gallium is a metal, and metals tend to lose electrons to become cations, so I will...

Homework Statement Here's the pic of the problem and my work The Attempt at a Solution I'm not sure how I'm suppose to calculate the energy change? Did i do it correctly in the picture? For number 9, I just added IE1 and IE2 and subtracted EA1 to get a total of 3200.3. This means that the...

Cheers everyone. Can the amount of water molecules added to a solution impact the formation of a salt with its ions mainly bonded through hydrogen bonds with electrostatic like behaviour? Let me give Some background to the question first: I am studying the precipitation of Phosphorous(P) as...

I was curious about the chemistry of radioisotopes. Specifically, when they form coordination compounds. What happens when they decay? I know a bit about tracer molecules, but what happens to the compound after it decays? Say a coordination compound containing a radioisotope as its center atom...

What happens to an atoms chemistry as the atomic number increases. In the case Berkelium, the electric charge from the nucleus is so powerful that the electrons must travel at relativistic speeds - becoming more massive in the process and leading to "new chemistry"...

Hello everyone! I'm currently a student about to get my AA degree at the end of the semester so the time has come for me to transfer from community college to university and, most importantly, decide on a major. Throughout my college career thus far, I've bounced around with ideas like...

The 2017 Nobel Prize in Chemistry is being announced tomorrow! I really can't wait to see what it will be awarded for, because it is always interesting and sometimes unexpected. I think it might be awarded for works on nanotechnology, because it is currently a hot field. It might be displayed...

<Moderator's note: Moved from a technical forum and thus no template.> OChem Question: My Answer: Not sure if this is correct. Anyone?

Homework Statement I'm having difficulties figuring out how many significant figures to report for several caluclations in my lab report. As it is a report, there are no specific problem statements. Homework Equations No equations, but there is a rule I was told: when dividing/multiplying I...

Hello, I have heard that the 2017 Nobel Prize in Chemistry is going to be announced in the next few months. Do you know about any interesting and/or useful discoveries that chemistry achieved worth the Nobel Prize in your opinion? Thanks.

Hello everyone I am doing some research about carbonic acid in fizzy drinks. I hope to find out how much carbonic acid was in the drink by looking how much CO2 bubbles come loose. but later I thought that there are two reactions that can take place: H2CO3 --> H2O + CO2 H2CO3 --> H+ + HCO3-...

I am in a chemistry class, and there was an in class example on how to do this type of problem, but then when I looked in the book, there wasn't an equation. the questions are related to what the wavelength will be when electrons are moving between orbitals.

i am confused with charge and valency of some formula. for carbon dioxide CO oxygen has a charge of -2 and carbon has a charge of +2. I thought though carbon is in 4 so its charge should be +/- 4.for nitrogen monoxide NO oxygen has a charge of 2- usually and nitrogen usually has a charge...

"for his studies of chemical processes on solid surfaces" i thought nobel prize was rewarded for the research which have some meaning to the chemistry. In this study i found it hard to find some meaning. what i found one was that some other techniques were developed because of doing this...

1. Question Statement and details : 500 mL of 56V H2O2 is kept in an open container due to which some H2O2 is decomposed and evolves 8gm O2 simultaneously, during the process some H2O also vapourizes.Due to all these changes final volume is reduced by 20%. Find final volume strength of H2O2...

Q : sample 0.2795 g containing only C6H6Cl6 (Mw = 209.8) and C14H9Cl5 (Mw = 354.5) precipitate AgCl 0.7161 g (Calculate %(C6H6Cl6) and %(C14H9Cl5) in sample) AgCl has 143.3 g/mol and 4.997 x 10-3 I get 0.2795 g = weight of (C6H6Cl6) + weight of (C14H9Cl5) mol of AgCl =...

I'm a student in Pre-med looking to begin self-studying chemistry at a meticulous level. Since I've only recently graduated I haven't been too full on my course load, and I'm ready to change that immediately. However, as a student, I have no clue how I might choose great authors who give a...

Can you immerse an electrolyte in an external electric field such that the ions are separated to a point that you could introduce electrodes and produce current in a load solely by virtue of the established charge distribution without electrode chemical interaction or galvanic potential as shown...

I'm wondering about the exact usage of the term entropy in programming vs. entropy in science.

Really struggling with this! Here is the data: Concentration of NaOH: .104M Mass of Aspirin #1: .367g Mass of Aspirin #2: .365g Volume of NaOH mixed with Tablet 1: 50ml Volume of NaOH mixed with Tablet 2: 50 ml Trial 1 Mass of Na2CO3: .065g Initial volume of HCl: 18.80mL Final Volume...

The topic in the prize is about GPCR and from what i have researched, the research is about biology. I want to know why it was rewarded to the field in chemistry.

I bought this book "Idiot's Guide to Quantum Physics" I bought it because I know I am an idiot in quantum physics. Now I have a question about the contents. It says that: "The four fundamental forces in nature (gravity, electromagnetism, plus two more that we'll formally introduce in Chapter...

I recently built my first distallation apparatus and in the process bought a few 105 bend take off adapter, however the angle isn't quite right and i cannot seem to source a 24/40 bent adapter/connector of any other angle! Is it just ebay/aliexpress or is 105 standard or something? I am...

Homework Statement What is the net heat flow of an aluminum disk (emissivity = 0.05) with radius 10 cm and temperature 293K placed inside a room where the temperature is 300K? Asurface = π*r2 = 0.01π m2 Homework Equations Hnet = A*e*σ(Tradiate4-Tabsorb4) The Attempt at a Solution By simply...

Doubts regarding the law of reciprocal proportions: What i have understood by reading the definition is that the ratio of the masses in which two elements A and B combine with a fixed mass of a third element C, will be a whole number multiple of the ratio of the masses in which A and B combine...

I'm looking for tested and proven technology for the high school chemistry class, can anyone suggest anything? It's a passion of mine to improve labs, and teaching lessons. Lately there has been a lot of emphasis on technology in the classroom. How do you implement any technology when there are...

Homework Statement for number 3,4,5 I'm still tryingHomework Equations PV/T = PV/T q = ΔU + W W = P ΔV The Attempt at a Solution (3) I used PV/T = PV/T to find the ΔT for each process for A→B I find PV/TA = P3V/TB ----- TB = 3TA (T increase) for B→C I find P3V/TB = 4P3V/TC ----- TC =...

Although LPG is a odourless gas , why can we smell it when it leaks? If possible,give the name of the smelling compound that is mixed with LPG?

During the summer semester, which is around 6-8 weeks. Chemistry 1 was a breeze for me, I scored an A. I've always liked physics in high school, but I've never done physics in over a year. Physics 1 holds 5 credits, and chemistry 2 holds 4 credits. I'm a biology major if that changes anything.

I'm looking for a way to determine the velocity a projectile can reach from expanding gasses (explosion or deflagration). I'm sure there are a lot of variables in here, but for reference, we can work with the 12 pounder Napoleonic cannon. The powder burning is 2.5 pounds of black powder made up...