Section Bank CP

[Manasir]

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#34: What mass of NaCl(MM=58.5 g/mol) was present in100 micrometers of the PBS solution. Correct answer is 585 ng.

Could someone lay out the math and thought process on this, I seem to get tripped on a lot of questions relating to unit analysis.

 

[kuzy]

(100x10^-6 L)* (0.1x10^-3 mol/L)*(58.5 g/mol) = 585 x 10^-9 g = 585 ng

The 100 mM comes from the passage if I remember correctly (just looking off of my notes)

I just took the real thing yesterday (woo! lol) and if I had one tip for calculations like this, it'd be to switch everything to SI units and put them in scientific notation before multiplying.

Also another pro-tip: you can find a reddit thread for most SB/FL questions if you look on google. Just type in something like "C/P section bank 34". The AAMC explanations usually leave a lot to be desired so just know you're not alone in your confusion haha good luck!

 

[Manasir]

Appreciate it! Thank you