How to make a solution using ethyl alcohol?

Hi doubleu,

I'm assuming that you meant 1% by mass. First you need to figure out how many grams of the powdered chemical that you want to use.

Let's say 1 grams. Therefore for every 1 grams of the chemical you use, you would need 99 grams of the 70% ethyl alcohol (ethanol). According to  the MSDS  from nafaa (http://www.nafaa.org/ethanol.pdf) the density of 70% ethanol is 0.79 g/mL. Therefore you would need 99 g / (.79 g/mL) = 125.316 mL of the 70% ethanol.

Bottom line, in order to make a 1% of the powdered chemical in ethanol, you would need to add 1 grams of the powdered chemical to 125.416mL of the 70% ethanol.

Hope this helps,
Laser

Thanks so much, I can take it from here

Hi Laser, I'm still not getting this, and I don't want to mess it up

I just obtained 50 mg of this pure substance.

How much ethanol (at 95%) do I need to use to make a 1% concentration of this ethanol + chemical mixture if I have 500 mL of ethanol available?

Hi doubleu,

How much of the pure substance (in grams) you want to use to make the solution? The amount of the ethanol used depends on the mass of the pure substance that you want to use.

Let's say you want to use all 50 mg or .05g of the pure substance. Then .05 would be 1% ===> 100% is 5 grams. So you want your solution (  pure substance + 95% ethanol) to have a mass of 5 grams.

mass of pure substance + mass 95% ethanol = 5g
           .05 g                  + mass 95% ethanol = 5g
                                       mass 95% ethanol = 5 - .05 = 4.95g

Then we take that mass divide by the density of 95% ethanol to get the volume needed.
4.95/.79 = 6.266 mL of 95% ethanol

Therefore you would need 6.266 mL of 95% ethanol for 50mg of the pure substance to make 1% by mass solution

Hope this helps,
Laser