[Foobarz]

Ok so as an AP chemistry student I struggle with the multiple choice number crunching questions (which do not allow use of a calculator). I was wondering if anyone had some tip or trick to crunch numbers faster?

[Borek]

If it is multiple choice often it is enough to just look at order of magnitude or at the approximate values. For example, if you are asked about solubility of a salt with Ksp = 5*10^-10 and you are given 0.12M, 2.2*10^-5M, 5.3*10^-7, 7.5*10^-10M answer is obvious for two reasons. First - square root of 5 is slightly above 2, second, square root of 10^-10 is 10^-5. There is only one answer that fits.

[Foobarz]

Thanks Borek!
Any other tips forum?