[LindziRae]

Hello!
I'm new!
Anyway, I do undergraduate research and I'm having the worst time of my life trying to figure out something that should be easy, unfortunately, my mind refuses to help me and I literally have no idea what I'm doing.
I have to make 10ml of .1ppm cyclohexanol .1ppm cylcohexanone in cyclohexane solution, then, using sequential dilutions make  .07, .05, .03 and .01ppm standards.

However, I can't figure out how to make the .1ppm solution.

I know I'll use cv=cv one I get the initial solution too, but... uh.

[Arkcon]

OK, we like to help.  Let's get started.  First of, can you define ppm?  There are many ways to define it, so you'll have to look around a bit to start.  Once you've found the starting point, you can us C₁V₁=C₂V₂

[LindziRae]

OK, we like to help.  Let's get started.  First of, can you define ppm?  There are many ways to define it, so you'll have to look around a bit to start.  Once you've found the starting point, you can us C₁V₁=C₂V₂

Well, everything is already in solution, but my professor keeps telling me 1ug /ml.

[Arkcon]

Well, what do those units tell you?  Write them out and think about it.  I was hoping you'd figure out what definition of ppm you were to use -- mass/mass, volume/volume, but it appears you will be using mass volume.  Do you see how I got that?

[LindziRae]

Well, what do those units tell you?  Write them out and think about it.  I was hoping you'd figure out what definition of ppm you were to use -- mass/mass, volume/volume, but it appears you will be using mass volume.  Do you see how I got that?

ug is a mass measurement but ml is a volume. I want to get it in volume/volume, since I have a what feels like every kind of pipette ever made at my disposal.
Would it be 10ug/10ml? Then, when put it into % I get .1

[fledarmus]

Hmmm, I think you need to start with an even more basic definition just to yourself. What does the abbreviation "ppm" stand for? (I believe this was Arkcon's first question)

[LindziRae]

parts per million

[fledarmus]

okay, parts of what per million of what? And what are you measuring "parts" in?

[LindziRae]

parts of cyclohexanone and cyclohexanaol per cyclohexane?

[Arkcon]

Lets try to use all the information we have to understand it completely.  You want 0.1 part cylcohexanone in 1,000,000 parts cyclohexane by volume.  You can't easily hold a million parts of cyclohexane (or can you, what units will you use for "parts"  milk jugs, or something smaller?) Consider, you'll need a tenth of a millionth of that unit of cyclohexanone.  That will be hard to measure, no matter how big your unit is.  Besides, you'll have to use the solution you've been given.  Can you begin to relate these various volumes to each other?  Now that all the definitions are out of the way.

[LindziRae]

The parts will be in ml?
I need to make 10ml.
Can you please just give me the answer explicitly, then I can ask about what I don't understand? All I need to know is much much to add into a 10ml volumetric flask.  I know it's really obvious, but I'm not seeing it and I'm starting to feel like a kindergardener instead of a junior in college.

[Arkcon]

I recognize this can be daunting, but you'd be better off if you gave it a shot on paper, then got in touch with an instructor tomorrow, and got more of the basics, and began to try to solve it for yourself.  You said you knew what to do eventually, so the task may become clearer sooner rather than later.

I don't want to give you the answer, it sets a bad precedent on this board, and I don't want you to miss a step, get it wrong, and blame me.  FWIW, your plan, for prepping the first dilution in a 10 ml volumetric ... simply won't work.