for elizabeth

Ok, first set up your road map. Say you’re doing a grams of A to grams of B. Your road map would be:

grams of A –> moles of A –> moles of B –> grams of B

Now, label your road map with numbers [or letters]. Grams of A = step #1, etc.

#1 —> #2 —> #3 —> #4

Then, set up your problem. Start with your question-mark-equals, and then from there, plug in your units before plugging in your numbers. Check out this pattern in reference to the numbered road map above; you’ll start out with #1, which is grams of A, yes? Your conversion factors will be #2 over #1, then #3 over #2, then #4 over #3.

#2 x #3 x #4
#1     #2    #3

which is

moles of A x moles of B x grams of B
grams of A    moles of A     moles of B

See how if you read in a circle from left to write and then down and back (basically clockwise), it reads “1, 2, 3, 4, 3, 2, 1”? No matter how many conversion factors you have, you should be able to read that circle, whether it’s “1, 2, 3, 2, 1” or “1, 2, 3, 4, 5, 4, 3, 2, 1.” As long as you have your road map in front of you, plug in the units, and then you won’t plug any numbers into the wrong places.


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