How to make salicylic Acid

nickyw · Post by **nickyw** » 09 May 2007, 15:19

Hi

This is probably a really lame request but can any tell me how to make
0.1M Salicylic Acid, Abscisic Acid and Ethylene I cant find the recipes anywhere.

Thanks for your help.

Nicky

Whspa · Post by **Whspa** » 10 May 2007, 08:56

Are you asking how to make these chemicals? If so, why

Carol

Lis · Post by **Lis** » 10 May 2007, 09:23

Hi Nicky,
if you use the formula
m(mass g)=FWxn(no of moles)
or- moles= mass(g)
FW
or -n= m
FW
or- n
m =FW
or- FWxn=n

for salicylic acid the equation would be ;
m = 138.12 x 0.1
m= 13.812g/L

ascorbic acid is
m= 176.13x0.1
m=17.613g/L

hope this has helped, you can use the same formula for all concentrations, just remember answers are in grams/L
the FW or MW is on the front of the bottle/jar

cheers Lisa

Jazz · Post by **Jazz** » 10 May 2007, 11:06

The easiest way to calculate mass of substrate to make solution of any molarity use formula
m = M x Mr x V

where:
m is mass in grams
M is concentration of the solution
Mr is molecular weight
V is volume in Litres of solution

Example :
Mr of Salicylic acid is 138.12
Desired molarity is 0.1M
And you need 0.5L
138.12x0.1x0.5=6.90gr
You need 6.7 gr of salicylic acid

Abscisic Acid Mr 264.3 0.1M 0.5L

264.3*0.1*0.5= 13.2gr

Ethylene glycol is little bit different because you usually make in %
The formula for volume percent (v/v) is:
[Volume of solute (ml) / Volume of solution (ml)] x 100
Example: to make 5% by volume of 5% ethylene glycol in water
Express % as a decimal 5% =0.05
Multiply this number with total volume 0.5L
0.05*500mL= 25ml (ethylene glycol needed)
Dissolve 25ml ethylene glycol in a little less than 450ml of water. Now bring final volume of solution up to 500ml with the addition of more water.
(This eliminates any error because the final volume of the solution may not equal the calculated sum of the individual components

nickyw · Post by **nickyw** » 10 May 2007, 12:30

Thanks Jazz and Lisa, I am new to this game and I panic when I cant find recipes for the solutions. I didnt know whether the salicyclic acid had to be mixed with water or something else like ethanol. So Carol the reason I wanted to know how to make the solution up was because it didnt dissolve very well in water so therefore did not look right. Now, at least I know I did the right calculations.

Cheers Nicky

Jazz · Post by **Jazz** » 10 May 2007, 12:50

Silly me, I forgot The most important thing ,solubility of Salicylic acid (1gr in 460ml of water) but to improve solubility dissolve desired amount of acid in absolute alcohol then add water.
As for Abscisic acid solubility is methanol: 50 mg/mL, may be clear to slightly hazy

nickyw · Post by **nickyw** » 10 May 2007, 13:48

Your a gem Jazz thanks heaps.

Nicky