Reactions Definition and 650 Threads

When an ROH is converted to an R--OTs, why must this mechanism be either Sn2 or E2?

"When the precipitating agent is added to the solution it causes it to become supersaturated. This starts the process of nucleation where ions and molecules will clump together to form small particles. A small amount of nucleation is necessary to start precipitation. However as the reaction...

So I'm looking for the reaction forces at the left end of the truss before I solve for the forces in the members of the truss in terms of F and theta. I summed forces in the x, y direction, took moments about point A,B, to get 4 equations in 4 unknowns (Ax, Ay, Bx, By). However, although Ax,Bx...

My chem textbook says that in precipitation reactions you lower the pH of the reaction in order for the precipitate to form quantitatively. It doesn't elaborate at all. What is the meaning of precipitate forming quantitatively?

Homework Statement The load per foot of beam length varies as shown. For x = 17 ft, the unit load is 373 lb/ft. At x = 0, the load is increasing at the rate of 41 lb/ft per foot. Calculate the support reactions at A and B. The reactions are positive if upward, negative if downward. I have...

I am a GCSE student and I am wondering why copper metal reacts with hot, concentrated sulfuric acid to produce copper (II) sulfate, sulfur dioxide, and water. Copper also reacts with hot, concentrated nitric acid to form copper (II) nitrate, nitrogen monoxide and water. Why do these reactions...

Hello again, sorry I had been idle for months. At that time I was relatively active in the Physics section. Thank God now I'm at the Fac. of Medicine, University of Sriwijaya. In the beginning of my college we had a Chemistry Lab Practice and are assigned to make the report, in which the...

In the case of nuclear fission, when U-235 splits into Ba,Kr and three neutrons , then it is shown that the total mass of the products on the right side of the equation is slightly less than that of the reactants on the left side. So this missing mass-the mass defect – is converted into energy...

I'm not really sure exactly if I'm doing these correctly but what stopped was the choice of adding 6 electrons to the left side.. This is what I did: This is their answer: I'm doing something wrong and I don't know why my answer is so different then theirs.

Nitrogen dioxide reacts with carbon monoxide by the overall equation: NO2(g) + CO(g) ----> NO(g)+ CO2(g) At a particular temperature, the reaction is second order In NO2 and zero order in CO. The rate constant is 0.515 L/(mol*s). How much heat energy evolves per second initially from 3.50...

So, I have a question regarding the method of joints used to solve force members in a truss. I am just starting the question and I am stuck on determining the moment in the support reactions. So my questions are: (1) For the moment around support reaction E do I include Force Dx in my...

Homework Statement The light right-angle boom which supports the 520-kg cylinder is supported by three cables and a ball-and-socket joint at O attached to the vertical x-y surface. Determine the reactions at O and the cable tensions. Homework Equations The Attempt at a...

Calculate the internal reactions for the member shown at the sections indicated; picture attached with FBD's I have the V & F forces correct but my moments are off. Can you point me in the right direction here? V M-M = 2k F M-M =-0.5k V N-N = -2k F N-N = 0.5k M M-M = -10k (2) +...

my class did a metal activity series lab where we added calcium to 8 different solutions. We have to write the net ionic equations for each reaction but I am stuck getting started on them. Ca(s) + Ca(NO3)2(aq) = ? my guess Ca(s) + Ca(NO3)2(aq) + 2H2O(l) --> Ca(OH)2 + H2(g) + Ca(NO3)(aq) This...

I am taking this course online, and in one of the slides there is this example, but i can't figure out the signs in the momentum formula. THANKS! so here is the exersice:

Making it short : Do gamma rays ALWAYS accompany a nuclear reaction?? I was thinking, since there are only three types of radioactive decay, alpha, beta and gamma. I don't quite understand how gamma radiation will always occur. Isn't it going to be just ONE of the three types? /Help :)

hi there, I've got three chemical reactions I'm struggling to put into 3d. 1) CoCl2.6H2O + en.2HCL --> rac-[Co(en)3]Cl3.0.5NaCl.3H2O (using NaOH and H2O2 as catalysts) 2) rac-[Co(en)3]Cl3.0.5NaCl.3H2O + (+)Tartaric acid --> [(+)Co(en)3](+)tart]Cl.5H2O 3) [(+)Co(en)3](+)tart]Cl.5H2O +...

I understand that spontaneous endothermic reactions are used rigorously in the design of instant cold packs to treat injures. Can someone please list and suggest other uses of spontanous endothermic reactions that can be used practically in everyday life

Is the statement Ke=k+/k- valid for all equilibrium constants like Ka, Kx, Kp, Kc? All of the expressions I have found for this statement relate Kc, k+ and k- only.

A Galvanic Cell is given. Write its Anode and Cathode half reactions, complete cell reaction and thus determine if the given is concentration cell. Pt|O_2(1\; atm)|NaO\! H(10^{-3}M)||H_2SO_4(0.5M)|O_2(1\;atm)|Pt I know that at anode, Oxygen will get oxidised, maybe from NaOH solution and...

dear all, in a series of experiments on the interaction between sodium hydroxide and other molecules such as water, Triton X-100, formaldehyde and others, we found emission of light. Besides the formaldehyde-NaOH interaction, i.e. the Cannizzaro reaction in which some intermediates may form...

I'm trying to figure out if the Helmholtz & Gibbs free energy are ever used outside of chemical reactions (I suppose they could be used in nuclear reactions in a plasma as well.) It seems to me that they are not, as I can only recall using them for chemical reactions in my thermodynamics course...

For the reaction, 2SO2(g) +O2 (g) ->2SO3. Why is it wrong to say that the reaction must involve a collision between one O2 and two SO2 molecules? Don't they form S2O6, which is equivalent to the product, 2SO3? What should I say then, about the reactants in forming 2SO3? Thank you so much!

Homework Statement a cantilever beam 5 m long with a mass of 100 N/m carries a concentrated load of 1000 N at its free end. The end of the beam is inserted into a wall 0.5 m thick. What are the reaction on the beam. Homework Equations The Attempt at a Solution My problem is I...

A Lithium-6 sample (m = 12,0 mg) which was isolated in ampule V = 200 cm3,was loaded in nuclear reactor and irradiated by neutrons for a long time. Calculate the maximal pressure in reactor, T = 400 K. The equation is Li + n = T + α I calculated the energy of this reaction using formula...

Homework Statement Hi all! I was wondering in two Feynman diagrams (1 and 2) 1) in an electron positron annihilation two photons are created. Now, is the virtual electron the exchanged particle? I'm having problems understanding the diagrams. 2) A proton decays to a neutron as a...

Title says it all. I've been wondering. The argument is, is there a minimal temperature required for any chemical reaction to reach its activation threshold? Or would the energylessness of the atoms prevent bonds from forming (or dissolving, I guess)? Conrad.

Let's say I have a solid, and hydrogen peroxide. I slowly release the hydrogen peroxide onto the solid, and both rapidly decompose yielding various compounds (I believe two will always be water and oxygen gas when dealing with hydrogen peroxide). What (solid) compound should I use to release the...

Homework Statement At 2600 K, ΔG° = 775 kJ for the vaporization of boron carbide: B_{4}C (s) ⇔ 4 B (g) + C (s) Find ΔG and determine if the process is spontaneous if the reaction vessel contains 4.00 mol of B_{4}C (s), 0.400 mol of C (s), and B (g) at a partial pressure of 1.0 x 10^-5...

Hi, I have a question of mass defects in nuclear reactions, and some preliminary questions about nuclear reactions in general. First of all, can all nuclear reactions be classified as either fission, fusion, or radioactivity? Is there a mass defect / conversion of mass into energy in a...

The question in the attachment is from an old entrance exam for medical school. The correct answer is B. I realize that if I assign a 'point value' to the levels of reactivity for each of the letters i.e. the more reactive the higher the number T = 1 Q = 2 M = 3 J = 4 and that if...

ionic/redox reactions need checking :) Hi again, I had a number of questions that I am not quite sure about. I've asked peers, although they seem confused too. 1. When you have NaOH + Fe2O3. xH2O would the sodium displace the iron, from rust, to form NaO3+ H2O? 2. Oxidisation-reduction...

I'm having trouble to understand which type of solvents are used in specific reactions When do you use polar aprotic solvents, polar protic solvents etc? And what makes DMSO, DMF , ether popular solvents?

Homework Statement Determine the reactions at rocker support A and pin support B.Homework Equations ƩF = 0 ƩM = 0 The Attempt at a Solution ƩFx = 0: -Asin(25) - (800lb) + Bx ƩFy = 0: Acos(25) - (500lb) + By I'm getting thrown off because of the rocker on an incline.

When metals such as sodium react with an acid, a salt and hydrogen gas is produced. and we know for sure the oxidation state of sodium in the compound will be +1. But for other metals such as iron, when they rest with acids which oxidation state do I use? I'm unsure if I'm supposed to use the...

I'm not sure what: BaCrO4(s) + HNO3(aq) would yield. Would the product of this reaction be: Ba(NO3)2(aq) + H2CrO4(aq)? Or, Ba(NO3)2(aq) + H2O(l) + Cr2O7(aq) ? If so, why is this?

Homework Statement Find spin, parity and isospin of second excited state of {}^{10}B nucleus, if we know that the second excited state (at E_x=1.74 MeV) can intensively be excited with reactions: {}^{7}Li(\alpha,\ n),\ {}^{9}Be(d,\ n),\ {}^{9}Be({}^{3}He,\ d), {}^{11}B(p,\ d), and cannot be...

Okay, I'm reviewing how to write reactions to determine which reactant should behave as the acid and which should behave as the base. I haven't seen this material in over a year and am actually trying to help someone out with a class. I know the ionic charge should balance on both sides...

That is, conscious decisions are said to be regulated by the prefrontal cortex, whereas inherited reactions (fear of snakes, etc.) are more regulated by the hypothalamus and the amygdala. (Yes, I am aware that this is something of a simplification, but this is valid enough for my question, I...

What is the equation I should be using for the following question: At 298K a cell reaction has a standard emf of +0.17V. The equilibrium constant for the cell reaction is 5.5 X 10^5. What is the value of n for the cell reaction. Grateful for anyone's help!

hi i was wondering if a carbonate will react with carbonic acid. such as calcium carbonate with carbonic acid: CaCO3+H2CO3CaCO3+CO2+H2O. Thanks for the help!

Please don't be bothered by my question, i know it sounds real elementary and it could easily be researched, but after doing so, i haven't been able to find anything on how or why the natural phenomenon of energy release takes place as chemicals react with one another. If you think about it...

I'm a physics student who's only taken one college chemistry class. I'm planning on taking the rest of the intro series for my own enrichment and a possible materials science minor, but that's going to come in bits and pieces due to my schedule. So between chemistry classes, I'm looking to have...

In one instance, my textbook says: (tert-butyl OH) + (HCl) ---> (tert-butyl Cl) + (H2O) In another instance: (tert-butyl Cl) + (H2O) ---> (tert-butyl OH) + (HCl) As you can see, there is a contradiction; the idea that reactions occur to achieve lower state of energy is broken since...

I know that the pivot exerts a vertical reaction equal to Cy = w0L / 2 and a horizontal reaction equal to Cx = 0. Does the pivot also exert a moment reaction? My intuition says that it doesn't and that it's actually not in equilibrium because it will rotate about the pivot, but the question is...

Would you "Hear" a Stars Nuclear reactions if you were close to it? Hey all, This is more of a thought problem, but last night I was wondering about what it would be like to see a star up close (relatively speaking). Since stars are essentially a massive nuclear chain reaction you would think...

To test the ability of Br2 and I2 to oxidize copper metal, the reactions take place between Br2water and I2 solution with copper: Cu (s) + Br2 (aq) -> Cu2+ (aq) + 2Br- (Aq) Cu(s) + I2 (methanol) -> Cu2+ (methanol) + 2I- (methanol). Write the net ionic equations describing the results of...

With regards to Wittig reactions, how does one know whether the cis or trans isomer is favoured? More specifically, can cis-stilbene be prepared in the attached Wittig reaction? Experimentally, the trans isomer was recovered. I realize that trans isomers are generally more stable, but am...

There are many reactions in which i don't understand what the role of catalyst is. Reactions like hydrogenation of alkenes , use of Ni i understand - it kinda breaks the hydrogen-hydrogen bond and provide it for the alkene. In contact process i.e. SO2 + 1/2O2 ----> SO3 catalyst is V2O5. I...

Hi guys ! I'm in serious need of help! Could you guys teach me how to attempt the following questions? I've tried everything..from reading up the notes(which has been trimmed along the years to make people pass)..to asking my teacher(He only explains briefly and in a way which i can't...