Dilution is the Solution

As today's BEDA topic is 'Teach Us Something!', I heavily debated telling you all about the work that I do. No, I don't think that you 'couldn't handle it'...I just didn't know if I really wanted to write about science, and thus mixing business with pleasure. My first idea was to explain detonation mechanisms...but as it turns out, I don't totally get them either. I'm working on it though. 

And then I realized that I use a very handy equation all the freaking time in the lab, and that it must be useful for something in real life. And so I give you:

The Most Useful Equation in the World: M1V1=M2V2.

When they teach you this in gen chem, M stands for Molarity (a measurement of concentration) and V stands for Volume. As it turns out, this works with any measurement of concentration and any type of 'amount' you want, be it mass or volume (provided it is compatible with your concentration measurement). For example, today I used it to make a 5% by weight solution of nitrocellulose, which comes as 70% in isopropyl alcohol. This is how I set it up:

concentration 1: 70%
amount 1: I measured it to be 5 g.
concentration 2: 5% (what I want it to be)
amount 2: the total amount; my unknown.

(5g)(70%)=(5%)(total mass)

total mass=70 g. Since I started with 5g, the amount of solvent that I needed to add was 70g-5g, or 65 g (then easily converted into mL using density, but that's not the awesome equation I'm teaching you).

So you may wonder, how on earth is this useful in real life? Since I've only been thinking about this for 10 minutes or so, the only thing I can come up with is Kool-Aid.

Say you screw the pooch and you didn't add enough water to your Kool-Aid (or Tang), and it tastes terrible. It happens (though usually the other way around, and if you're using Kool-Aid in packets, this equation won't help you...or actually it would, but I don't know how you would measure the amount you'd boil off at home). So you want to add more water to it, but how much to add?  

Simple.

amount 1: How much do you actually have?

concentration 1: how much Kool-Aid is in there to how much water?

concentration 2: how much Kool-Aid should be in there to the water

amount 2: your unknown, the final volume.

And POOF, perfect Kool-Aid.

Also, you can use this to determine how much booze is in your Jell-O shots and mixed drinks.

For simplicity, just say you're using one kind of liquor.

amount 1: the amount of booze

concentration 1: the percentage of alcohol in said booze

amount 2: the total amount of Jell-O with booze or mixed drink

concentration 2: your unknown; the percentage of alcohol in your finished product.

I should have figured that out in college...