Converting from mol/L to mmol/mL

Question

On my lab report sheet, I am asked several times to convert concentrations and standard deviations from mol/L to mmol/mL and asked to show the unit conversion calculation required. I am confused, however, because the values for the two are equivalent to each other. Am I perhaps missing something here? 

Answer 1

To convert mol/Lt into mmol/mL you will have to know that a mol has 1000 mmols and a L has 1000 mL then to make the conversion you will have to multiply the two parts of the expression, dimensionally by 1000, then if you treat this as a fraction that has been multiplied by the same number in numerator and denominator, the fraction remains the same. so the two terms will be the same. mol/L is the same concentration as mmol/mL