Before I start, please don't flame, I'm tired. And when I'm tired I get frustrated and can't figure the most basic of things (especially math).

Okay so if there was a ratio for product XYZ and you needed an exact ratio of

85.5% of A which is measured in grams
14.5% of B which is measured in milliliters

I don't know how to keep the ratio constant with the both of them measured completely different.

So, would I measure these chems in parts? Like say no matter what I use (grams, milligrams, lbs) I have to use 8 and a half parts of "A" and 1 and a half parts of "B"?

This should be simple, but for some reason it isn't.

Well that really depends on the specifics, such as if it is just a mixture or if something is being synthesized. Sometimes people give the ratios for a mixture of a liquid with a solid already factoring in that the liquid will be measured a different way. Something like 85 grams of AN and 15 ml nitroglycerin for example

If we're producing something that requires a synthesis, then your best course of action would probably be to find the specific gravity of the liquid and use that to find how many grams are in each ml. You would want to be looking at molar amounts really.

Again, it would be easier to answer with some more specifics.

Most good instructions should specify the amount to measure meaured. Such as 16:1:3 g:L:mL or something like that. If it isn't then most common measurent is to measure all ingredient by wieght or by volume.

Also in chemical standards % is understood to mean percent by wieght unless otherwise specified.

For the particular mixture it just says its measured by weight. So if it's measured by weight its the same as measuring in parts?

Only if each "part" is weighed. 3 parts x and 2 parts y would be 3 grams x and 2 grams y. Volume is never ever used for solids. Only for liquids. And if you want accuracy, you would do well to convert that measurement of volume into one of mass.

assuming of course the liquid being added isn't a solution :P then you got more math on you hands lol

I got it thanks.

Correction, volume is RARELY used for solids. Sometimes you can get away with measuring volumes of solids, if for example your solid has particles on a known, consisting size, or for say mortor, one part sand to one part cement can be by volume. Also with plant growing media you usually measure by volume.

Of course parts per million is another game altogther.

I can hardly understand you. And in CHEMISTRY volume is not used. Learn stoich and you will understand why.

Let's hypothesize that I know a 100-mL graduated cylinder filled with a particular granular charcoal from a reliable chemical supplier masses 32 grams more than the empty cylinder because you're friend let you use his scale real quick. If in the future I needed to use 10 grams of charcoal in a preperation, then I could fill the cylinder to just about the 32 mL mark and be relitively accurate with the measurement. Volume is a property of solids and can be used to measure them.

Granted it's not as accurate as a good scale, it is still far more accurate than just guessing, even if it is a rarely used technique in pure and applied chemistry.