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Finding orders from initial rates

Please Help in finding orders with respect to o3 and c2h4

Exp O3. C2H4 Initial rate
1 0.5. 1.0. 1.0
2. 2.0. 1.0. 4.0
3. 4.0. 2.0. 16.0

Since in experiment 1 and 3 the concentration of c2h4 doesn't changed I have found that the order with respect to o3 is 1st order

What is the order with respect to c2h4?

ALSO

Exp. NO. H2. Initial rate
1. 0.10. 0.20. 2.6
2. 0.10. 0.50. 6.5
3. 0.30. 0.50 58.5

The order with respect to H2 is first order but what about NO?







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Reply 1
once you have used the data to work out the order wrt ozone using expt 1 and 2 you have to use that fact when comparing expts 1 and 3.

same with the 2nd problem
Reply 2
I'm not sure how to actually work it out, I have in my head the order wrt C2H4 being second but I'm not sure how to work it out. If anyone could help?


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Reply 3
Original post by Northern-lad
Please Help in finding orders with respect to o3 and c2h4

Exp O3. C2H4 Initial rate
1 0.5. 1.0. 1.0
2. 2.0. 1.0. 4.0
3. 4.0. 2.0. 16.0

Since in experiment 1 and 3 the concentration of c2h4 doesn't changed I have found that the order with respect to o3 is 1st order

What is the order with respect to c2h4?

ALSO

Exp. NO. H2. Initial rate
1. 0.10. 0.20. 2.6
2. 0.10. 0.50. 6.5
3. 0.30. 0.50 58.5

The order with respect to H2 is first order but what about NO?







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If the order wrt c2h4 is 1st order (which I think it is), then the order wrt o3 is also 1st order (going from exp. 2 to exp. 3 multiplies conc. of c2h4 by 2, which would put the rate at 8. The conc. of o3 also doubles going from exp. 2 to exp. 3. Doubling the 8 gives the 16, so the order wrt o3 is also 1st order).

Order wrt to H2 is 1st. I've found that the order wrt NO is then 2nd order. This is how I got it:
58.5 divided by 6.5 = 9
conc. of NO is tripled going from exp. 2 to exp. 3 (where the 6.5 and the 58.5 come from, respectively - the conc. of H2 stays the same)
square root of 9 = 3
so conc. of NO is 2nd order

Hope this makes sense. PM me or something if it doesn't.:3

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