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guiromero

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- Homework Statement
- Assume that a material has an activation energy for substitutional self diffusion migration energy of 250 kJ/mol and a Do prefactor of 100 mmm2/s. Calculate the following quantities for this material (express all your answers in units of mm2/s):

a) Calculate the vacancy diffusion coefficient at 750°C"

- Relevant Equations
- D = Do * exp(-Ea/RT)

Hello,

I have a doubt in a question from a chemistry MIT course:

My attempt is attached. The formula given in the lecture is D = Do * exp(-Ea + Delta Gn)/RT

However, they don't explain what Delta Gn is, I suppose it is Gibbs free energy, but as the statement doesn't give any other extra energy value despite of the activation energy (Ea), I didn't include Gn in the equation.

The correct answer is: 5.5e-8 mm2/s.

Does anyone have knowlege about this subject and would be able to help me?

Thanks a lot.

I have a doubt in a question from a chemistry MIT course:

My attempt is attached. The formula given in the lecture is D = Do * exp(-Ea + Delta Gn)/RT

However, they don't explain what Delta Gn is, I suppose it is Gibbs free energy, but as the statement doesn't give any other extra energy value despite of the activation energy (Ea), I didn't include Gn in the equation.

The correct answer is: 5.5e-8 mm2/s.

Does anyone have knowlege about this subject and would be able to help me?

Thanks a lot.

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