How do you find how many miles are in 4 g of NaOH?

I imagine you meant to ask for number of MOLES rather than miles! To convert a mass of a substance to moles of the substance, divide the mass by the molar mass (aka formula mass. Na = 23.0 + O = 16 + H = 1.01 = 40.0-g/mol)

4.0-g NaOH x (1 mole NaOH / 40-g NaOH) = 0.1 moles NaOH

Miles are a measure of distance, so I'm guessing your question is supposed to be how many moles are in 4g on NaOH.

This is a simple conversion. Simply find the molecular mass of NaOH. To do this grab your handy periodic table and look at each of the elements.

Na=23 grams/mole

O=16 grams/mole

H =1 grams/mole

Add up all the numbers to get 40 grams per mole. This is the conversion factor we need. Set up your equations like this:

(4g NaOH)*(1mole NaOH/40 gramsNaOH) = 0.1 moles NaOH

See how g NaOH cancels with g NaOH on bottom? this is how you know you set it up right and all you're left with is moles on top!