Question

To prepare 5 millilitres of a 10 millimolar solution of glucose from a 1 molar stock solution of glucose you would have to add X microlitres of stock and Y mL of water, what are X and Y

Answer 1

(5ml)(10mM)=(1000mM)(Xml)

X=$\frac{5ml×10mM}{10mM}$

X=$0.05ml$

Convert to microliters

1$ml$ =1000microlitres

$\therefore0.05ml$ =

$\frac{0.05ml×1000microlitres}{1ml}$

X=$50microlitres$

$1000ml +0.05ml=(5ml×10mM)+y$

Divide both sides by 1000mM

$\therefore$ Y=$(1000ml+0.05ml-0.05ml)$

Y=$1000ml$