Hey Guys,
Cramming for finals, and here's a problem I got wrong on one of my old exams that's pretty easy, but I just can't do!
"A cementite formation reaction follows the the equation:
t=Aexp(Q/RT) where t is in secs, Q the activation enegery, R the gas constant (1.98 cal/mol-K), an T is the absolute temperature. If it takes a substance 0.1s to start forming at 600 degrees C, an at 500 degrees C it starts after 10 s, how long will one have to wait for the substance to form at 400 degrees C?"
If someone could show me the steps, that would be great.
I started doing the following and got two equations:
(1) ln 0.1=ln A - Q/R(873)
(2) ln 10= ln A - Q/R(773)
But now what? Do you take the ratio of the two? Then what? Thanks for any help!
Cramming for finals, and here's a problem I got wrong on one of my old exams that's pretty easy, but I just can't do!
"A cementite formation reaction follows the the equation:
t=Aexp(Q/RT) where t is in secs, Q the activation enegery, R the gas constant (1.98 cal/mol-K), an T is the absolute temperature. If it takes a substance 0.1s to start forming at 600 degrees C, an at 500 degrees C it starts after 10 s, how long will one have to wait for the substance to form at 400 degrees C?"
If someone could show me the steps, that would be great.
I started doing the following and got two equations:
(1) ln 0.1=ln A - Q/R(873)
(2) ln 10= ln A - Q/R(773)
But now what? Do you take the ratio of the two? Then what? Thanks for any help!
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