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Topic: Half life (Read 2871 times)
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UG
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Half life
«
on:
May 28, 2010, 06:16:16 AM »
Hi, how does one find the half life of a reaction such as
d[Cl
2
]/dt = k[Cl
2
]
1.5
?
Does it involve integrating? If so, how
?
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sjb
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Re: Half life
«
Reply #1 on:
May 28, 2010, 07:48:01 AM »
How would you do it, working from first principles, if it were first order?
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UG
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Re: Half life
«
Reply #2 on:
May 28, 2010, 08:37:36 AM »
Integrate it
d[Cl
2
]/[Cl
2
] = k dt which becomes c - ln[Cl
2
] = kt
At t = 0 [Cl
2
] = [Cl
2
]
0
and so c = [Cl
2
]
0
Or ln([Cl
2
]
0
/ [Cl
2
]) = kt
After one half life [Cl
2
] = [Cl
2
]
0
/2
Or ln([Cl
2
]
0
/ ([Cl
2
]
0
/2)) = kt
1/2
Giving ln(2) = kt
1/2
and t
1/2
= ln 2 /k
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sjb
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Re: Half life
«
Reply #3 on:
May 31, 2010, 01:26:50 PM »
So follow a similar approach to the reaction order you have.
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Topic: Half life (Read 2871 times)