Activation Definition and 95 Threads

Hi.. How to calculate the activation energy of oxidation of Si. For example, from the Arrhenius plot (parabolic constant versus 1000/T (K-1)).

Hi, I hope someone can help me with these question I have about fission? Where can I find a list of what the activation energy is between the normal state of the nucleus and the state where it splits. In my book it says the activation energy for U-235 is 5.3 MeV(The energy required to fission...

I know from the movie that paper burns at fahrenheit 451. I guess this refers to the activation energy paper and oxygen require to react into CO2 and water. I have been trying to understand the Arrhenius equation which I think is the key to predicting at what temperature a reaction will take...

Homework Statement I'm a little confused as to the concept of activation energy, transition state, and reaction intermediates...For example, I know that the activation energy is the difference between the ground state of the reactants and the transition state but on a diagram, does the top...

Homework Statement I have to find activation energy of PZT sample using arrehnius plot , i have ln(conductivity) v/s 1000/T plot , i calculated the slope from the graph , then what will will be the next step to calculate Ea ? formula is : ln(conductivity) = Aexp(-Ea/KT) where A is the...

Homework Statement A reaction is found to have an activation energy of 38.0 kJ/mol. If the rate constant for this reaction is 1.60 × 102 M-1s-1 at 249 K, what is the rate constant at 436 K? Homework Equations...

"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...

Hi As you progress down groups one and two, the elements become more reactive. This is because the ionisation energies of the elements decreases [outer electron further from the nucleus] so the proportion of colliding molecules that have sufficient energy to overcome the activation energy...

In a typical General Chemistry textbook, quantitative treatments of activation energies begin with the Arrhenius equation, which is given (not derived). When R and T values are properly inserted with the given units, the activation energy comes out with the unit of J/mole. My Question 1...

the question is like this: Calculate the activation energy needed to create a single vacancy in aluminium, given: T= 500 Celsius Density (500 Celsius) = 2.62 gr/cm3 n = 7.57e23 m-3 Mw (Al) = 26.98 gr/mol I know these Formulas: n = N*exp (Q/kT) (k = boltzmann's constant) N =...

For the decomposition of one mole of nitrosyl chloride, Delta H = 38kJ. NOCl(g)-->NO(g)+Cl2(g). The activation energy of this reaction is 100kJ. Calculate the activation energy for the reverse reaction in kJ. I attempted this question but cannot find the process or equation to finish the...

I am not asking how to make this reaction. Please do not lock this thread just because it happens to contain the word "thermite". I am simply asking for information about this process for research involving silica. The Goldshmidt process between silicon dioxide and aluminum is expressed by...

Homework Statement \ (From a past exam paper) Na-24 can be produced by irradiation of 27-Al with energetic neutrons. It decays by beta emission. An aluminium sample of mass m=0.2g was irradiated by energetic neutrons for a period of 1 hour. Two hours after the end of irradiation the total...

When you have a current inrush from turning on a devise, does that mean there is actually less resistance for that brief amount of time?

I've been trying to find a definitive answer to this question since long, and I still haven't found one! My teacher at school says that it can't be zero, according to the Arrhenius equation. She says if the activation energy were to be zero, every collision would result in a reaction, which...

Hi everyone, Question In metals, for homogeneous nucleation, activation free energy required for the formation of a stable nucleus are different when the nucleus are considered as a cube and considered as a sphere and the relation between them is energy for cube is almost double of the...

Homework Statement Calculate Ea from given info: ln k = 0 t(sec-1) = 0.0033 ln k = -0.2 t(sec-1) = 0.00335 ln k = -0.4 t(sec-1) = 0.0034 Homework Equations ln k = -(Ea/RT) + ln A The Attempt at a Solution I could find Ea if i had the temperature but...

Homework Statement I know that temperature and kinetic energy are related, so as temperature increases the energy of the reactants as well as the amount of collisions and bonds formed, increases. I take this as meaning that the rate increases. But I also read in my organic book that in...

Can anybody help me out to find Activation energy of adsorption and in that rate constant? i am confused ...please help me out? thanks

Can you give me an example of a reaction where the activation energy is reduced?

Homework Statement For a lab, I need to find the activation energy of an experiment from plotting the Arrhenius plot. I have the half-life time of the reaction at various temperatures. Homework Equations -Temperature (K) 318 322 327 331 338 -ln k -6.17 -5.89 -5.65 -5.33...

Please I need some help. I'm working on a chemistry question and have to determine the activation energy for a reverse reaction. How do you do that? I've looked all over my text and through my notes and cannot find a clear way on how to solve it. Thanks.

[SOLVED] Activation energy The reaction, 2NOCI (g) = 2NO (g) + Cl^{}_2{}(g) , has rate constant values for the reaction of NOCl of 9.3 x 10^-6 Is at 350 K and 6.9 x 10^-4 Is at 400 K. Calculate the activation energy for the reaction. What is the rate constant at 425 K? I am unsure how to...

[SOLVED] Activation Energy related to rate. The activation energy for the reaction : 2N_{2}O_{5} (g) \rightarrow 2N_{2}O_{4} (g) + O{2} (g), is 103 kJ/mol. The gas constant is 8.314 J/mol*K Using only information given in this problem calculate the temperature at which the rate of the...

Please can someone help. I am having trouble with the following question involving the production of nitric acid: What is the value for the enthaply change for reaction 2NO(g) + O2(g) 2NO2(g) and what is the activation energy for the forward reaction. I think the answer for the...

Homework Statement The overall activation energy E is 60 kcal/mol. Reaction steps are: CH3CHO --> .5CH3CO + .5CH3 + .5H2 E1 = 80 kcal/mol CH3CO --> CH3 + CO E2 = ? CH3 + CH3CHO --> CH4 + CH3CO E3 = 10 kcal/mol CH3 + CH3CO --> minor products...

The activation energy of a certain reaction is 45.8 kJ/mol. At 20 degrees celsius, the rate constant is 0.0130 s^(-1). At what temperature would this reaction go twice as fast? Arrhenius Equation:k = Ae^(-E_a/RT) ln(k_2 / k_1) = (E_a /R)(1/T_1 - 1/T_2) Okay, so I'm not quite sure how...

I've looked around and not found any good sources on the gamma energies from fast neutron activation. I need to find the characteristic gamma rays for an MCNP project and currently, I'm relying on energies I get from running some simple cases I set up for the element of interest. Does anyone...

Hi, It is stated that changing the medium - water to ethanol f.ex - the experimentally measured rate enhancement is 10^6 fold which leads to a lowering of the activation barrier of \approx 9 kcal/mol. I don't quite understand which parameters I am missing in order to calculate that? Any help...

1. given/known data My work is about calculating activation energy of bromate/bromide reaction. Besides KBr and KBrO[SIZE="1"]3, phenol and methy red is also used. The Bromine produced react rapidly with phenol, once all the phenol is consumed, the bromine will decolorize the methyl orange...

Homework Statement In Houston (near sea level), water boils at 100.0°C. In Cripple Creek, Colorado (near 9500 ft), it boils at 90.0°C. If it takes 5.6 min to cook an egg in Cripple Creek and 4.5 min in Houston, what is Ea for this process?What I do not understand is how I can figure this when...

Homework Statement A certain reaction, with an activation energe of 64.5 kJ/mole, is run at 25.0'C (degree Celsius) and its rate is measured. How many times faster would this reaction be if it were run at 50.0'C (degree Celsius)? Homework Equations I think: (Arrhenius equation)...

I guess I have installed Windows XP Home on my computer too many times, and now I am not being allowed to "activate windows" (it says: According to our records the number of times you can activate windows with this product key has been exceeded.). That is quite possibly true, I have installed...

1) Methanol can be produced by the following reaction: CO (g) + 2H2 (g) --> CH30H (g) How is the rate of disappearance of hydrogen gas related to the rate of appearance of methanol? -delta[H2]/delta t = ? a. + delta [H2]/delta t b. + 1delta[CH3OH]/2delta t c. + 2 delta...

I know that when you increase a reaction at room temperature (25 degrees) by 10 degrees it doubles the reaction rate, but what activation energy is implied by this? :confused: I would really appreciate it if someone could let me know as i have no idea.

This question comes from a study guide and I can't get it. Any help would be greatly appreciated. A number of experiments were performed to determine the effect of the temperature on the rate constant, k, for the reaction X + Y --> Z which had been determined to be first order in X. The...

Is activation energy dependent? I think it isn't, but if you rearrange the Arrhenius equation you get: Ea - activation energy Ea = RT(lnA - lnk) so as temperature Ea can change. But I am thinking that k will also change in relation so Ea is constant?

Hey , I still do not understand how to determine the activation energy for the reverse reaction when you are given the activation energy for the forward reaction and the delta h for the reaction. I was told to draw an energy diagram but I think I am drawing it wrong. I do know that the...

Is there a website where I can find out what isotope I have if I know it's half life and energies of the beta particles emitted?

hi! I am having serious problem at plotting the graph for the reaction between Bromide ion and Bromate(V) ion in Acid Solution. The Arrhenius euqation is: k= Ae^{-E_a/RT} Taking logarithms on both sides, the equation becomes: ln k = ln A + E_a/R (1/T) So generally, a graph of ln k versus...

hi, could some one please verify what i have done here or tell me where i went wrong. suppose the activation energy for a chemical reaction is E*, i have to work out how the rate of the forward reaction depends on temperature T and concentration. (note: i am given the Boltzmann distribution...

Hey guys; I've a question. How do enzymes lower the free energy of activation? My thinking is that the enzyme binds, and when it binds it alters the shape of whatever it binds to, and the altered shape is energetically favored to the unaltered shape for the reaction. This is purely...

is there a way to tell the activation energy for a reaction mathmatically just based on what the reaction is, or what it contains? or do you just have to know what it is, based on looking off a table or some other way of finding that data. lets say I have a hypothetical reaction: X + Y -> XY...

does anyone here has any idea what is froth flotation(in extraction pf metals) and negative energy of activation( as in chemical energetics)? thanks for any input.

What makes compound,lets say oxygen and hydrogen explosive?I think electrones are loosing energy but I"m not so sure.How this all works?.Please help me.