# Confused about mM and mmols and ml and L - HELP MEH! (Nov/20/2010 )

Ok so I am confused about mM, I understand that 1M = 1mol/L and I am fairly certain that 1mM = 1mmol/1L (please correct me on this if I am wrong). But I do remember a problem where e.g. 1mole was divided by 50 ml and the resulting unit was mM...is this right? Please help and include any example problems too that would clarify, Thanks!

>> Ok so I am confused about mM, I understand that 1M = 1mol/L and I am fairly certain that 1mM = 1mmol/1L

You are right.

>>But I do remember a problem where e.g. 1 mole was divided by 50 ml and the resulting unit was mM...is this right?

Here the question is whether 1 mole is quantity (solute) or concentration (solution). If it is quantity, you add 1 M solute into 50 ml solvent, you will get a 20 M solution (1 M / 0.05L = 20 M/L). If it is concentration, you have to give the amount to calculate the final concentration.

please make it clear...is it 1mole solute in 50 ml solvent? if it is so then answer should be 20 M or 20000mM.

tihong10 on Sat Nov 20 21:50:07 2010 said:

Ok so I am confused about mM, I understand that 1M = 1mol/L and I am fairly certain that 1mM = 1mmol/1L (please correct me on this if I am wrong). But I do remember a problem where e.g. 1mole was divided by 50 ml and the resulting unit was mM...is this right? Please help and include any example problems too that would clarify, Thanks!