# Kinetics helpWatch

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#1
Someone explain to me how these two questions are done please:

http://gyazo.com/ff233deabc2f549a92f6670c7a29d817

How did they go from 2k to k?
Surely you would times by 103 to get it into moles, then x 1/60 to get it into s-1 then divide by 2?

Everytime i do this i get an answer not on the page...
So; slope: -0.0000416 (rate of change) x -1/2 = 0.0002083 mmoldm-3s-1!

Anyone help?!
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#2
Oh can someone confirm these for me to.

http://gyazo.com/d9ff691affb8b7aef5a9f804a077e12b D
http://gyazo.com/129532e28727ee151fece2bac78b82f1 B

http://gyazo.com/82695265b3f1d7b6d177fa9829d7850d Not sure; if it halfs in 20 mins, it will go down by 4 in 40 and therefore go down by 8 in 60 mins? So none of the above?
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4 years ago
#3
For Q1:

2k = 0.024 dm3 mmol-1 h-1
There are 3600 seconds per hour (i.e 3600 s hr-1), so to convert 2k from h-1 to s-1 divide by 3600:
2k = 0.0000066 dm3 mmol-1 s-1
There are 1000 mmol per mol (i.e 1000 mmol mol-1), so to convert 2k from mmol-1 to mol-1 multiply by 1000:
2k = 0.0066 dm3 mol-1 s-1
k = 0.0033 dm3 mol-1 s-1

For Q2 I think you might be over complicating it:
just workout the concentration change over the full 52 mins, convert that change to per mine, and then finally convert that value to per second
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4 years ago
#4
(Original post by TheAlchemistt)
Oh can someone confirm these for me to.

http://gyazo.com/d9ff691affb8b7aef5a9f804a077e12b D
http://gyazo.com/129532e28727ee151fece2bac78b82f1 B

http://gyazo.com/82695265b3f1d7b6d177fa9829d7850d Not sure; if it halfs in 20 mins, it will go down by 4 in 40 and therefore go down by 8 in 60 mins? So none of the above?
Just did these for you.
http://gyazo.com/ff233deabc2f549a92f6670c7a29d817 C
http://gyazo.com/d9ff691affb8b7aef5a9f804a077e12b C
http://postimg.org/image/pt0wg62q5/

http://gyazo.com/129532e28727ee151fece2bac78b82f1 C
http://postimg.org/image/7zlk7xje5/

http://gyazo.com/82695265b3f1d7b6d177fa9829d7850d
http://postimg.org/image/i1jp4zglr/ A
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#5

Thanks for this,

I feel so stupid, after posting that i went back and got the same thing you did. Think i was half asleep xD

Thanks anyway!
0
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