# How to work out order when the concentration is not constant ?Watch

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#1

Glucose is zero order
KMnO4 is first order
H+...??
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2 years ago
#2
It's first order. The best way I can explain it is to work out what you'd expect to happen, then account for any differences.
So, you know glucose is 0 order, so ignore that.
You know KMnO4 is first order, so ignoring H+, you'd expect the rate from experiments 3-4 to increase by 4, because that's how much the conc increases by. This should give you a rate of 4x10^-5, but it gives you double that.
You need to account for the remaining 4x10^-5. You can see that H+ doubles, so in order for the remaining 4x10^-5, to double, the rate must be proportional since H+ doubles too.
Hope that helps.
0
#3
(Original post by typicalvirgo)
It's first order. The best way I can explain it is to work out what you'd expect to happen, then account for any differences.
So, you know glucose is 0 order, so ignore that.
You know KMnO4 is first order, so ignoring H+, you'd expect the rate from experiments 3-4 to increase by 4, because that's how much the conc increases by. This should give you a rate of 4x10^-5, but it gives you double that.
You need to account for the remaining 4x10^-5. You can see that H+ doubles, so in order for the remaining 4x10^-5, to double, the rate must be proportional since H+ doubles too.
Hope that helps.
Thank you 😊
0
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