A mol is a unit but also has a magnitude. How can a unit have a magnitude? And if mole is used to measure an amount of substance than what does mass measure?

  • $\begingroup$ I don't understand what is being asked here. Strictly following your logic, there is no difference between mass and volume, or even between any extensive properties whatsoever, which is just wrong. $\endgroup$ – andselisk Nov 18 '19 at 17:51
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    $\begingroup$ Maybe the language got a bit complex. I simply want to ask why there is a need of both mol and mass to measure the amount of a substance $\endgroup$ – Yashvik gupta Nov 18 '19 at 17:57
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    $\begingroup$ If you have 1 mol of O2 and 1 mol of N2, do they have the same mass? No, moles and mass measure 2 different things. At least I think this is what you are asking. $\endgroup$ – airhuff Nov 18 '19 at 19:30

Mole itself doesn't have a magnitude, but the value of mole does, in fact it is the magnitude. Any measurement has a magnitude (ie for the mass of 5 kg the magnitude will also be 5).

I think you are confusing it with scalar measurements (ie forces) which also have a direction. For example 5 Newtons 'in that direction'.

Mole is similar to a dozen (just a bit larger). It is used to count how many atoms, molecules, atoms or anything else there are.

If you think about mass as "the amount of stuff there is in an object" you can confuse it with mols

but the actual definition of mass is:

A property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied.

which is different to mols (which is used to count objects).

  • $\begingroup$ Thanks a lot !! $\endgroup$ – Yashvik gupta Nov 21 '19 at 19:02

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