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Offline fsmmuglig

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2 Questions
« on: June 18, 2020, 07:11:16 PM »
Hello, dear colleagues. I nesse some help in 2 questions.

1. At 800 ºC, one out of 10^10 atoms and at 900 ºC one between 10^9 atoms have enough energy to move within a solid. (a) What is the activation energy in cal/mol? (b) in wich temperature will there be one out of 10^8 atoms with enough energy to move?

2. What is the MgO / FeO ratio, by weight, of the solution shown in the figure? If all ions of Fe of the figure were replaced by Ni ions, what would be the percentage and weight of MgO?

I would really appreciate if you could help me.
Thank you!
« Last Edit: June 19, 2020, 03:17:34 AM by Borek »

Offline Borek

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Re: 2 Questions
« Reply #1 on: June 19, 2020, 03:18:21 AM »
You have to show your attempts to solve the problem to receive help, this is a forum policy.
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Offline Enthalpy

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Re: 2 Questions
« Reply #2 on: June 19, 2020, 04:41:33 PM »
For 1., you're probably expected to apply some distribution. So which one would fit here? If you write the number of atoms with enough energy at 800°C and 900°C, can you identify an activation energy from the two equations?

In the question, I don't like the implicit suggestion that any atom with enough energy can move. The lucky atom must also be near some crystal imperfection that eases the movements.

And cal is a deprecated unit. J is the energy unit.

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