In a reaction between magnesium and hydrochloric acid, I measured the change in mass of the magnesium strip (Initial weight: 0.03g). I calculated the the time for the reaction to reach completion. A sample set of data we collected for during our investigation was:

With 8 molar of HCl the reaction took an average of 15.49 seconds to completely evolve into hydrogen gas.

To calculate the rate of reaction, I used the formula:

Formula for calculation of rate of reaction

I suppose, change in mass would be 0.03 g as we went to the completion of the reaction, and change in time would be noted as the average time 15.49. My question is, what is the unit supposed to be in this formula?

  • 1
    $\begingroup$ I think you are making this too complicated. According to the units you've given and the formula you've used, your units would just be mass/time or g/s. Or, the official SI unit for mass is actually kg, so if you want that you would convert to kg/s. $\endgroup$
    – airhuff
    Commented Aug 16, 2017 at 1:32

1 Answer 1


The formula has been stated and you simply need to look out for the units of the quantities from the formula. Mass(g)/Time(s). Which is g/s.


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