A2 Chemistry
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I am trying to analyse the Ea between Mg and HCl. I got 16 kJ mol-1. Surely this is too low? What have I actually got to say because I have already determined what activation energy means?
Ulex replies
Your value does seem to be rather low but at least you have something to discuss! You need first of all to refer to the values obtained by other students (see the Re:act website for this). You then need to assess your possible error range. When you did your Arrhenius plot, how appropriately did you choose your straight line? Could it possibly have been drawn a little steeper? If so, this would make a difference to your calculated activation energy.
Look at your method again. Did you, perhaps, time the collection of a certain volume of hydrogen and work out an average rate from this? If you did, the volume you chose might have been too high, which would give too low an average rate.
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updated: 11 November 2007
