RR= c/t

[RR] = mol/l s

so tell me how come you take the concentration c and not the actual amount of the substance c or a volume V for calculating RR

Whether or not you're concentrating on the task at hand will have a profound influence on it's success and speed (within this study).

If I am absentminded, then the results will obviously be different from the results of me concentrating on the exercise.

That's my best shot at it anyways

haha^^
notsureifsrs, no offence

TBH, I'm not sure if I'm serious either

It's been a harsh as hell morning and I'm completely out of it.

Makes matters worse that I have a practical in an hour and it's a doozy -.-

Because different substances will have different amounts of moles in the same mass or volume, you use moles because a mole is universally defined as 6.022E23 molecules of substance regardless of what it is.

You use concentration rather than the exact amount of the substance because that tells you how much of the substance is contained in a given volume.

For example, it's sort of like if you were in a field and there were dandelions, and a "reaction" occurred whenever you step on a dandelion. Now, which piece of information helps you more in finding out how often you will step on a dandelion: the fact that there are 1000 total dandelions in the field (without the size of the field given), or that the average density of dandelions per square meter (i.e. moles per liter, in a solution) is 1 per square meter?

In aqueous solutions in basic chemistry, you assume the mixtures are homogeneous so you don't have to worry about things like varying concentrations in different parts of the beaker, etc