MOLE TO MOLE CONVERSIONS

Some chemistry questions...

REN FLORES asks: Mr. Doktor? When are we ever going to need mole to mole conversions?

IVY GLORIA: Yeah Mr. Doktor! I dun geddit. Mole to Mole? How is that a conversion?

MR DOKTOR: Well, you see, let's say you know how many moles of a compound is reacting in an equation. Once you have the reactions and a balanced equation, you may need to know how many moles you end up with. It's useful to have when you need to know the end result of a chemical reactions. The process is easier to explain in examples than in words.

ADRIENNE ROSS *hand raised, skin glowing*: Oo! Oo! Me! Allow me to show them some brilliant examples! (and quickly so I can go back to watching and starring in pretty little liars!!!)

MOLE TO MOLE CONVERSIONS

Coefficients in balanced equations tell us the # of moles reacted or produced

They can also be used at conversion factors

THIS IS VERY VERY VERY IMPORTANT. ALWAYS REMEMBER:

*****WHAT YOU NEED OVER WHAT YOU HAVE******

IVY GLORIA: Goodness! Wha does dat mean?

ADRIENNE ROSS *huge white smile, skin glowing*: Well, here's an example. If you know you have 0.15 moles of methane consumed in a combustion reaction, and you want to know how many moles of CO2 are produced, start off by writing out the equation...

First of all, you need to know that methane is CH4...

Next, balance out the equation...

Now, here is where the WHAT YOU NEED OVER WHAT YOU HAVE part comes in *cute, but mature sounding, giggle*.

We NEED to know how many moles of CO2 is produced, so we take the coefficient of CO2 and put it over (or divide it by) what we HAVE. What we HAVE is the moles of methane, so take the coefficient of methane and divide the coefficient of CO2 by it.

So it's pretty easy from here on out. We multiply 0.15 moles of methane by 1/1 and we get moles of CO2!

REN FLORES: Oh I get it now!

ADRIENNE ROSS *huge smile, glowing skin*: Great! Here are 2 more examples for you to practice with, then get more practice by doing your homework worksheets!