Posted 06 February 2011 - 12:00 PM
But the information that I was given for this question is as follows.
mole weight of k2HPo4 =174.18 and mol weight of kH2Po4=136.06
to make phosphate buffer at required ph, use Xml of 0.2M KHpo4 and Y ml of KH2Po4 where Xml=36 and Yml=14,
I am not sure if I have to use this information
Posted 06 February 2011 - 02:08 PM
your idea of making a higher concentration then diluting is common practice.
make up a volume of each phosphate (take care to include hydration in the formula weight) at 1M. then, take one and add the other until you reach the desired pH. don't worry about final volume (unless it is too little) because no matter the volume the concentration of phosphate will remain the same.
then dilute as needed.
ps- there are tables available that give the proportions necessary for various pHs and for various buffers.
genius does what it must
i do what i get paid to do
Posted 16 February 2012 - 04:00 PM
104g disodium phosphate heptahydrate
Posted 19 February 2012 - 09:31 AM
dont worry here is the link how to prepare your desired solution concentration, by mass? by volume or by dilution
Posted 22 February 2012 - 02:11 AM