Weak Definition and 473 Threads

Procedure: 1. Pipette 25 cm3 of ethanoic acid into a conical flask 2. Titrate against 0.1M sodium hydroxide solution in the burrette, using phenolphthalein as indicator. 3. Pipette further 25 cm3 of ethanoic acid into the solution after titration and mix throughly. Questions: 1. what is...

Homework Statement Titrating .1006M CH3COOH with .2012M NaOH. pKa=4.74, Ka=1.8*10^-5 What is the pH at the equivalence point of the titration? Homework Equations pKa = -log(Ka) pH = -log[H+] The Attempt at a Solution Alright, after setting up an ICE table (in order to find...

http://postbiota.org/pipermail/tt/2007-May/000515.html Does anyone know what happened with these experiments?

Hi I was studying the WLLN and the CLT. A form of WLLN states that if X_{n} is a sequence of random variables, it satisfies WLLN if there exist sequences a_{n} and b_{n} such that b_{n} is positive and increasing to infinity such that \frac{S_{n}-a_{n}}{b_{n}} \rightarrow 0 [convergence in...

Homework Statement For the weak field metric g_{00}=-1+\epsilon h_{00}+O(\epsilon^2) g_{\alpha\beta}=\delta_{\alpha\beta}+\epsilon h_{\alpha\beta}+O(\epsilon^2) Prove R_{00}=-\frac{1}{2}\epsilon\frac{\partial^2h_{00}}{\partial x^\alpha\partial x^\beta}+O(\epsilon^2) Homework Equations The hint...

I encountered an argument that says that the weak mediators must be massive because the weak force is short range, by the uncertainty principle. But isn't the uncertainty principle relates the uncertainty in mass, \delta m and \delta t and not the absolute value of the mass?

Homework Statement A hydrogen atom, which is in its ground state 1s (i.e. \|1,0,0\rangle), is put into a weak time-dependent external electric field, which points into the z direction: \boldsymbol{E}(t,\boldsymbol{r}) = \frac{C\hat{\text{\boldsymbol{e}}}_{z}}{t^{2}+\tau^{2}}, where C and...

strong and weak electrolytes-need help pleasez hi all i need help to solve the following exercise Given: those are a strong electrolyt limiting , and we give the molar conductivity for each ion in ( S.Cm2/mol) HCl 426.1 CH3COONA 91.05 HF 405 NaCl 126.5 1- why did thos electrolyts has...

strong and weak electrolytes-need help pleasez hi all i need help to solve the following exercise Given: strong electrolyt limiting molar conductivity of ion i ( S.Cm2/mol) HCl 426.1 CH3COONA 91.05...

Homework Statement We did a lab in class about weak acid/strong base titration, but I'm having a bit of trouble. We we only given the molarities of an unknown weak acid and a strong base (NaOH) and the pH of six different mixtures containing different mL of the two, which is below: Test...

Homework Statement Show that if {x_k} is any sequence of points in space R^n with |{x_k}| \rightarrow \infty , then \delta(x-x_k) \rightarrow 0 weakly Homework Equations The Attempt at a Solution I'm still trying to grasp the concept of weak convergence for distributions. It...

Hi, i just need to get together all the conservations/violations that the weak interaction conserves/violates. I know about parity, charge conjugation and basic properties such as charge and lepton number but i was wandering if anybody could think of any more. No mathematics please! Thanks.

Homework Statement I had a whole list of reactions and had to show whether or not they could occur... I understood most of the reasons, bar the following, but was more confused about whether or not a reaction was strong or weak... I know that if the reaction involves a lepton its weak, and if...

Hi I have been trying several days to solve this problem. But i can't find the procedure to solve this weak acid and weak base problem. I will really appreciate some help. What is the pH of a soft drink in which the major buffer ingredients are 6.90 g of NaH2PO4 and 5.70 g of Na2HPO4 per...

Hi I have been trying several days to solve this problem. But i can't find the procedure to solve this weak acid and weak base problem. I will really appreciate some help. What is the pH of a soft drink in which the major buffer ingredients are 6.90 g of NaH2PO4 and 5.70 g of Na2HPO4 per...

25 mL of 0.1 M HOAc are titrated with 0.15 M NaOH. What is the pH at equivalence? I know that the pH at start will be greater than 1.0 and the pH at equivalence will be greater than 7 since its a titration of a weak acid and a strong base. But what I don't know is whether or not there is a...

Can someone explain to me briefly what is weak localiztion and anti-localization and its effect on magnetotransport? Thank you.

Take the sequence x_n = (1-1/n)e_n in l^2 Consider the map l^2 to R given by x |--> ||x||^2 The set A = {x_n} in l ^2 is closed & its image is not closed in R under the norm topology (it doesn't contain its accumulation point 1). So ultimately the above map is not closed. What I'm...

Hey guys, I don't know what I should do. I mean I love biology...but its just that I have tried those methods which are suppose to make memorization easier for you but it still is pretty hard(relating the word to your senses or memory). What do you guys think?

gravity and weak force is it possible to compare the strength of weak force to gravity and if so how is weak force stronger than gravity?

I came upon a very interesting article today: http://www.msnbc.msn.com/id/19875410/site/newsweek/ I wanted to confirm what I read... this is the first time I ever heard of this kind of thing, and I was wondering if any of you have seen this before. It talks about a tweak of Young's...

Hello, Just wondering if anyone could post some resources on lewis acids: ie weak to strong lewis acid ranking or maybe some table or chart of lewis acids and their reactivity I haven't been able to find any resources thus far regarding lewis acids and their reactivity rankings... ...

Well, I have trouble understanding the definition of the weak product of a family of groups, which states that it is the set of all f \in \prod_{i \in I} G_{i} such that f(i) = e_{i} \in G_{i}, for all but a finite number of i from I (Gi is a family of groups indexed by the set I). The bolded...

when you're doing RICE tables for weak acid/base reactions, when do you neglect x? thanks for ANY input :biggrin:

How come in the weak field approximation, where the metric is equal to, ds^2=-(1+2phi)dt^2 + dr^2(1-2phi). where of course dr is the three distance. why is phi multiplied by 2? I have two more stupid question regarding a different approach. please just explain it to me as i want to to see...

The Ph of 0.3mol/l of a weak base is 10.66, calculate kb. I was thinking of using ph and calculate the concentration of H ions and then calculate poh and OH, but don't know what to do next. Any ideas?

If one would make no assumtions to try to simplify, except for just assuming OH- were negligible in a solution of weak diprotic acid, H2A, we can create four equations to represent concentrations for : H2A == H + HA- HA- == H + A- Each of those has a K value for equilibrium constant...

e^+ e^- \rightarrow \mu^+ \mu^- The reaction above can take place in two different ways: 1) The electromagnetic interaction by exchanging a \gamma 2) The weak interaction by exchanging a Z^0 Can somebody explain which way is more probable and why. I'm not sure but I guess that the...

Question: TRIS is a weak base. Compute pH of a solution containing .050 moles of TRIS and .020 moles of HCl in a total volume of 2L. pKb for TRIS is 5.92. Use RNH2 to represent TRIS. Equation: pH = pKa+ log ([conjugate base]/[acid]) Work: change equation for pOH: pH = 14-pOH pOH =...

Homework Statement I'm making a table on excel with the calculated pH of the solution vs the actual measured pH from the lab. My problem is finding the pH of a acetic acid-acetate buffer that has been titrated with HCl, once the moles of HCl are greater than the initial quantity of mols of...

Homework Statement Sketch curve of pH vs volume of base added for the titration of 50.0ml of 1.00M acetic acid with 1.00M sodium hydroxide. Homework Equations none, i think. The Attempt at a Solution Okay, first off, this is a weak acid, the first point on the curve would be the initial...

Homework Statement Cross-sections for weak interactions at an energy E increase with E as E^2. Show that the rate of weak interactions in the early universe depends on the temperature T as \sigma_{wk} \propto T^52. The attempt at a solution The only formula I can find is \sigma_{wk} = g_{wk}^2...

Hello! I need help with an exercise about the weak interaction: How do the mass, the q-value and the vertices depend on the half-lifetime of a decay? The myon decay has a half-lifetime of 0.0000015 seconds, the neutron decay has a half-lifetime of 607 seconds. Why is there such a big...

As far as I understand type systems in strongly typed system such as the one found in Java you must specify the exact type of the variable. Like e.g. int x = 5; // strongly typed also this would fail Object x = 5; Object y = "Not soo strong are we?"; Object z = x + y; // would throw a...

Gravitational lensing (GL), first mooted in 1924, is now a technique being used by astronomers to detect dark matter. Lensing depends on the bending of light by the gravity of a mass concentration, such as a galaxy or galaxy cluster. In glass, it is the spatial gradient of the optical path...

I was wondering if someone could answer these questions? It is obvious that the forces due to electromagnetics are due to the transfer of photons. What particles are responsible for the strong and weak forces in the nuclei? Are they massless like photons (which would imply that they travel...

"If 0.5g of sodium acetate is dissolved in water, what would you expect to find in the resulting solution"? Is it acetic acid, acetate, or hydroxide? I don't know how to set this one up

Hi All! Preliminaries: Let H denote the Hilbert-space, and let A be a densely defined closed operator on it, with domain $D(A) \subset H$. On D(A) one defines a finer topology than that of H such way that f_n->f in the topology on D(A) iff both f_n->f and Af_n->Af in the H-topology. Let...

I am slightly confused about the following statement from my chemistry book: "Note that essentially all solid ionic compounds are strong electrolytes in solution, because, no matter to what extent they dissolve, they give only ions" (https://www.amazon.com/dp/0030312914/?tag=pfamazon01-20)...

Considering the decay of certain exotic mesons, such as the following: B^{+} --> D^{0} \pi^{+} Apparently the decay proceeds via a weak interaction where multiple W boson exchanges occur. I was trying to nut out how this actually occurs, and draw up a sensible Feynman diagram...

could the equation - pH=pKa+log([A]/[HA]) - be applied for the case of strong acid? Although the percentage of dissociation of strong acid/base is very high, there still exists a equilibrium, right? secondly, if i tried to explain the resistance in pH of buffer *in terms of* the above...

Is it possible that one day, the Earth magnetic field get so weaken that solar wind could strip off water from earth? I ask this because of this article which leads me to draw the parallel. http://www.geotimes.org/sept04/NN_solarstorms.html

Hello, I would like to see more clearly the differences between the various forms of the equivalence principle. When reading about it on http://en.wikipedia.org/wiki/Equivalence_principle" I have the strange feeling that the difference is too small and too easily accepted to justify the...

If the conjugate base of a weak acid ends up being determined as a weak base by dividing the acid dissociation constant by the ion product of water, how can this be? My book had an example, but goes on to generalize that if a salt's anion is the conjugate base of a weak acid, then the salt...

Looks like I really don't have a feel for it. So I was working on this the other day. (arranged in order) http://img218.imageshack.us/img218/9613/1gx9.jpg http://img68.imageshack.us/img68/4677/2te4.jpg http://img68.imageshack.us/img68/7853/3jg9.jpg...

The idea of weak and strong emergence seems to be one that is easily confused. I've seen numerous mentions of "emergence" in the literature without classifying which they are talking about. Many times it seems the author wants to imply strong but is really only looking at a weakly emergent...

Given c=1, weak field approx for g: g(/mu,mu)=eta(/mu,mu)-2phi Derive eqn contiuity: d(rho)/dt+u(j)rho,j=-rho u(j/),j (all der. partial) Given T(mu,nu/)=(rho+p)u(mu/)cross u(nu/)+pg(mu,nu/) using divergenceT =0 i.e.T(mu,nu/;nu)=0: Step in the proof is Gamma(0/mu,j)u(mu)=-phi,j I get...

If all four fundamental forces were once unified and equal, why is gravity so much weaker than the other three forces?

I was asked to do a problem about the gauge freedom one has in the weak field limit in general relativity. I am given a coordinate transformation x^{\mu '} = x^{\mu} - \zeta^{\mu}. Now I have to show how the perturbation of the metric transforms under this coordinate transformation. The result...

I have read that, on the scale of clusters (million light years) the effect of the expansion of the universe is 10 million times smaller than the gravity binding the cluster. So space time, (flows) through the cluster (like a super fluid) or akin to a group of logs staying in a fixed...