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# dm^3 and dm^-3 watch

Is 0.0025 moldm^3 the same as 2.5moldm^-3
2. The units are not the same so you can't compare them like that.
It's like saying is 5 meters the same as 0.005 kilograms.
For moldm^-3 you say it as mol per decimetre cubed.
For moldm^3 you would say mol decimetre cubed.
I'm not sure you understand the notation properly?
3. when you have trouble with units, think about the equation and apply the units.
This becomes very important later when you do equilibrium and for Kc you need units which is different pretty much every example.

for example, the c=n/v formula.
That's concentration=number of moles/volume
concentraiton= mol divided by dm3 (volume is generally done like this, always convert to dm3 unless it's the ideal gas equation)
concentration units is therefore mol/dm3
however from some maths:
1/x=x^-1
mol/dm3= mol multiplied by 1/dm3
1/dm3=dm^-3
therefore concentration= moldm^-3.

This is hard to learn word for word but if you can get your teacher to explain it it is very simple and goes a long way.
4. (Original post by Rob.x)
Is 0.0025 moldm^3 the same as 2.5moldm^-3
mol x dm³

and

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