Reactions Definition and 650 Threads

  1. A

    Reversible and irreversible reactions

    I need some clarification on the following points on the reversible and irreversible reactions. In the examples cited in textbooks, for reversible reaction, isothermal expansion and compression are given. But the adiabatic exp and comp are not given. Why is it not included in the list...
  2. A

    Oxidation of Alcohols (KMnO4) - Preferred Reactions?

    Given that KMnO4 oxidises primary alcohols to aldehydes and secondary alcohols to ketones, and that in a mixture secondary alcohols will oxidise first (correct?). What's the order of preference of primary alcohols that will most readily oxidise first. The highest molecular weight first...
  3. L

    Are ionic bonds results of redox reactions?

    Because if redox is the transfer of electrons between atoms, and ionic bonding is when one or more electrons go are transferred from one atom to another, wouldn't that mean it is basically a redox reaction?
  4. P

    Sn2 Reactions and Solvent characteristics

    I am having trouble figuring out why this statement is true, especially the bolded sentence: "When the nucleophile and/or electrophile have a formal charge, SN2 reaction rate is fastest when the solvent is of modest polarity. When the nucelophile and electrophile are both neutral, SN2...
  5. J

    Fictional iron chemical reactions

    I am a mechanical engineer who is writing a science fiction novel where a means has been discovered to temporarily reduce the mass of the nucleus of certain 56Fe atoms. When a certain field is applied to the iron, it gets lighter. When the field is removed, the iron regains its original mass...
  6. Z

    Solving Redox Reactions: MnCl2 & Cr2O72-

    Homework Statement I have two problems- 1) Given the cell- Mn(s)|MnCl2(c1)|HCL(c2)|O2(p atm)|Pt How do we write the chemical equation taking place at cathode? Is it H2O ------> 2e + 2H+ + 0.5O2 ? How do we identify the reaction? 2) Write the half cell involving the reaction - Cr2O72-(aq)...
  7. O

    Will Injecting O2 into an Equilibrium System make More Materials Radioactive?

    be A Equilibrium System (the reaction is Endothermic). if Will inject into the System Ne(g) How will this affect the balance in the System ? i will get more2HI Because Le Chatelier's principle?, For example if i will inject into the System more Hydrogen gas i will get more 2HI. but...
  8. T

    Determining Reactions for Cantilever and Simply-Supported Beam Loads

    Beam ABC has a 3m cantilever span AB and a 10m simply supported span BC. The beam has a design loadings as follows: load case 1, 28kN/m UDL along span BC. Load case 2: 36kN point load at the end of the cantilever at A. For each of the load cases, determine the magnitude of the support...
  9. K

    Thermodynamic Irreversible Reactions

    Hopefully somebody can help me with this. I have a final exam next week, and the textbook we use along with my professor didn't do a good job explaining what happens in irreversible reactions. More specifically, what differences are there between reversible and irreversible processes of...
  10. M

    Exploring Equilibrium Reactions: Questions & Answers

    1-The concentration of water,solid substances and precipates should not appear in the equilibrium constant equation Kc , why?I don't understand.Please don't tell me that because their concentration remains constant whatever their quantities. because I have read these words tens of times and I...
  11. H

    Electrical Any interesting reactions at 500kV? This might be DIY-able

    I just realized a Van de Graaf generator around 400...500 kV might be easily doable, by an average amateur working in a garage. I was also thinking these days about a DYI cyclotron project, which I scrapped because the magnet is just too hard to make and feed. But then I figured the Van de...
  12. O

    Chemical reactions according to equation

    Homework Statement 12.8 gr of O Flowed over 100 gr hot Al. and i got this reactions equation: 4Al(s)+3O2(g)--->2Al2O3(g) a)how many gr Aluminum oxide Al203 Created through a chemical process ? i know i need to find the number of moles of oxygen which flowed. and the number of...
  13. D

    Low Energy Nuclear Reactions" (LENR): What Do People Think?

    General consensus on Cold Fusion better known as "Low Energy Nuclear Reactions" LENR? I was wondering for those that know. What is the general consensus on Cold Fusion which is actually not cold fusion at all but "Low Energy Nuclear Reactions" LENR? The term cold fusion was made by the media...
  14. X

    Quick question about differences of energy output for different reactions

    I am trying to set up some realistic conditions for a game I am designing, and need a bit of help. I am speaking very generally in this context. What are the percentages of mass released as usable energy in a uranium fission reaction, a D-T fusion reaction, and a positron-electron annihilation...
  15. K

    Stoichiometry of Precipitation Reactions

    Homework Statement What mass of iron(III) chlorate is needed to precipitate all the chromate ions from 234 mL of a 0.100 M lithium chromate solution. Homework Equations The Attempt at a Solution we just started precipitates and my teacher didnt explain the procedure very well...
  16. S

    Endothermic Reactions: Coupling & Cooling Environment

    Hello, Are all endothermic reaction take their energy from a coupled exothermic reaction? Is it possible that an endothermic reaction would take it's energy from the physical process of cooloing the environment? If so- why are there so many coupled reactions in cell biology if it can just take...
  17. J

    Explaining Bonding & Mass in Chemical Reactions

    This at first may sound like a question based in chemistry, but I feel it is more of a particle physics question. When a chemical reaction occurs, it can be exothermic or endothermic. It is my understanding that if bonds are formed, energy is released, and when bonds are broken, energy is...
  18. L

    Neutralization reaction: NaCl + H2O

    This is a subject I am unfamiliar with, and was just wondering where I should start in order to learn about them and how they affect different elements and form other substances step-by-step. From what I know, an Acid donated a Hydrogen Ion, and a Base takes a Hydrogen Ion, and an Acid has to...
  19. L

    Determine the tension in cable BC and the reactions at A.

    Homework Statement The 400N weight of member AB acts at its midpoint. The length of member AB is 3m. Determine the tension in cable BC and the reactions at A. Homework Equations m=rxf? maybe simple force equations The Attempt at a Solution Not sure whether to use sum of all forces...
  20. U

    Reaction Rate Order for High Temperature Gas-Solid Reactions

    Hello chemists! In the classical treatment of reaction kinetics, the overall reaction rate is usually written as a constant times the concentration of species raised to some power (called the order of reaction for that species). It is impressed in high school level students that this reaction...
  21. W

    Are there any chemical reactions that can generate radio waves?

    I know that chemical reactions can emit light and heat, and these are part of the electromagnetic spectrum. But are there any chemical reactions that can directly produce electromagnetic emissions in the radio part of the spectrum?
  22. S

    Completely safe nuclear reactions?

    Do exist some nuclear reactions which are completely safe and produce no radiation whatsoever? And those radioactive materials could be used as convenient energy storage? For example,I know there exist such reaction as electron capture during which electron is captured, but not emitted.You...
  23. J

    Why Do Some Chemical Reactions Take Time?

    Why some of the chemical reactions are slow? Is it directly proportional to the size and shape of the molecules - since the complex shape makes 2 molecules less probable coming in contact with the appropriate alignment for the chemical reaction to happen? I'm trying to find an answer within...
  24. E

    Are all neutralization reactions exothermic?

    Homework Statement When acid gets on your skin, why must you flush the area with plenty of water rather than neutralizing with a base? Homework Equations The Attempt at a Solution I'm guessing it's because neutralization reactions are exothermic so heat could be released, thus...
  25. D

    Reactions of NH3 & CuSO4 + H2SO4 & Cu(NH3)4+2

    Homework Statement What is produced when NH3 is mixed with CuSO4(aq)? What is produced when H2SO4(aq) is mixed with Cu(NH3)4+2? Homework Equations None The Attempt at a Solution For the first one, I'm thinking I should treat ammonia as a Group 1 metal and do a single...
  26. J

    Are these Nuclear Reactions permitted?

    1. Homework Statement Which of the following Nuclear Reactions are allowed? A) e- + p --> \mu- + p B) n --> p + \pi- C) K- + p --> (anti)k0 + n 2. Homework Equations While I don't know if there are any relevant equations, I know that there are several conservation laws that are required...
  27. J

    Chemistry Homework: Second Order Rate Equation and Calculating Rate Constant

    Homework Statement Is this first or second order rate? Calculate the rate constant and be certain to give its units. A-->products Chart A (mM) / Time 1 / 0 .5 / 11 .25 / 20 .1 /...
  28. L

    Spontaneous reactions require activation energy?

    "Spontaneous" reactions require activation energy? To my understanding reactions are considered "spontaenous" if they require no additional energy for the reaction to occur. However, they require activation energy. Why is activation energy not considered "additional energy?" The term...
  29. M

    Reactions of calcium carbonate

    Hi What is the reaction of calcium carbonate and water. I thought it was insoluble but I was looking up some notes from a chemistry practical i did and it says CaCO3(s) + H2O (l) → Ca(OH)2(s) + CO2(g) Can someone please explain this reaction for me as I can't find it on the internet...
  30. S

    Do essential amino acids undergo transamination reactions?

    Checked google no satifying answer.Thanks :smile:
  31. D

    Vertical reactions of pin supports of a weightless Beam with a UDL applied

    Homework Statement The question is: The weightless beam, ABCD, shown in Figure below is supported by a pin support at B, and a roller bearing at C. There is a 4 kN/m UDL along the whole beam, as shown. There is an 11.2kNm clockwise couple at A. The vertical reactions of B and C...
  32. B

    Looking for interesting reactions with paper

    A friend asked me for an interesting way to destroy a boxful of flashcards for a video scholarship. Being almost the 4th of July, I mentioned making some kind of fireworks out of them, but I want to give him something a little more... safe and legal. I tried looking on Google for chemical...
  33. W

    Continuous oscillating reactions?

    Hello. Are there any chemical reactions of the Briggs-Rauscher variety that will continue to oscillate indefinitely with continued agitation? B-R fades out after a few minutes of agitation, and I am curious as to whether there are oscillating reactions that will continue to oscillate as long as...
  34. I

    Combustion/explosion reactions

    combustion/explosion reactions - anyone have an explanation? I am a layperson, desperately seeking enlightenment! I have been thinking about combustion/explosion reactions and have been trying to build a mental model of the physical processes involved. I can imagine two atoms, let's say...
  35. S

    Finding the reactions of a ladder against the floor & wall

    Homework Statement [PLAIN]http://img571.imageshack.us/img571/4411/statics.jpg A Man weighing 180lb has climbed 60% of the ladder shown. The ladder weighs 30 lb. Find the forces the wall & floor resists (reactions). The angle the ladder makes with the floor is 60 degrees. Homework Equations...
  36. S

    Statics Question regarding Joint type & Reactions

    When solving for reactions in a 2D diagram as seen below, how does each type of joint affect the summation of forces in the x & y components? My problem asks to find the summation of forces in the x & y components, and has a smooth pin connection in the left of the beam and roller on the right...
  37. S

    Are These Reactions Possible? Understanding Conditions for 2NaOH+K and HCN+K

    hello, I would like to know if following reactions are possible/correct and under what condition: 2NaOH+K->KOH+NaOH and HCN+K->KCN+H Theoretically it should be possible but I'm not sure,Please help me understand Thanks
  38. P

    Salt Bridge Reactions: Fe2+ & Mg - Which is Correct?

    Does it matter which way I have the solutions? i.e. is this correct (in a reaction between iron and magnesium): Fe2+ | Fe || Mg | Mg 2+ Or is this correct: Fe | Fe2+ || Mg 2+ | Mg Or are they all correct, as long as I have them on the correct sides of the salt bridge?
  39. M

    Help with writing half reactions for the following

    [b]1. Fe2+ + MnO4- -> Fe3+ + Mn2+ (acidic solution) 2. I need to write a half reaction for the oxidation and reduction process and I am totally lost. If I could have help on this one, maybe I will understand how to complete the balance of my work.
  40. M

    Are gamma rays produced in fusion reactions?

    Lots of articles and papers I read talk about the gamma rays produced during fusion reactions. And yet, when I look at equations for fuel cycles, the sum of the energies of the fusion products equals the total energy liberated. Since this implies that all of the energy released in the fusion...
  41. H

    Nuclear Reaction Threshold Energy Calculation

    Homework Statement Hi, I'm trying to find out the formulae that gives me the threshold energy for a nuclear reaction (i.e. The minimum amount of energy required to induce a reaction). I've got a question which states an endothermic reaction of : O + p --> F + n has a Q value of...
  42. J

    Mass lost in chemical reactions?

    Homework Statement In chemical reactions, when energy is released, mass is lost according to Einstein’s formula just as it is for nuclear energy (though the amounts lost are so small that for centuries scientists thought that mass was conserved). When a kilogram of coal is burned, it...
  43. T

    Balancing Redox Reactions in Acid & Basic Solutions

    Homework Statement V205(s) + U(s) ---> V0 2+(aq) + UO2 2+(aq) *Balance the rxn under acidic conditions. *Balance the rxn under basic conditions.
  44. Q

    Binding energy and endothermic reactions

    from masteringphyics.com, ||\\\\\\\\ the binding energy of a nucleus is defined as the difference between the rest energy that the individual particles would have if they were not bound in a nucleus and the rest energy of the nucleus itself. So, stated another way, fusion reactions are...
  45. P

    Are exothermic reactions spontaneous?

    The reaction between 2KOH + H2SO4 -> K2SO4 + 2H2O is exothermic... However is this reaction spontaneous as well? If so then why? the concentration that i used was: KOH - 2M H2SO4 - 1M (I writting a lab report on the "course of this reaction"...spontaniety of the reaction is a...
  46. S

    How can I solve equations involving Grignard reagents?

    i have propkem solving this equations attempt to solve i looke out in http://www.fsj.uAlberta.ca/CHIMIE/chem161/ReactionsofGrignardReagents.html http://cnx.org/content/m15245/latest/ http://www.chemguide.co.uk/organicprops/haloalkanes/grignard.html...
  47. C

    Calculating Vertical Load on a Gantry Beam: Tips and Tricks | Physics Forum

    Homework Statement Hi there! I have recently studying how to design gantry. but I got one problem about how to calculate the vertical load on the beam. can anyone help me and let me know how to find the Reactions 114kn and 183kn in the picture. and I know how to find the max bending moment...
  48. R

    Finding reactions at points on truss

    I honestly don't know how to approach this problem. I am to find the reactions at C and E. Since E is a roller, it will have moment, but since C is a pin, it won't have moment? What exactly do I need to figure out before attempting to write the equations for the reactions? Do I need to find the...
  49. R

    How to Find Reactions at Point A in a Structural System?

    I am to find the reactions at A. Am I doing this right? Do I also need to find Ax? If I do, would it just be Ax - 400cos30 = 0?
  50. T

    Can a Catalyzer Also Be an Intermediary in Chemical Reactions?

    Can a catalyzer in a reaction be an intermediary as well? Im not sure, i don't think because it would have to consume it self...
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