Explanation: To find the mass of the sample in grams, all you have to do is convert. You need to multiply 0.170 mol by the unit multiplier 115.89 grams PNC12 (molecular mass - rounded) / 1 mol PNC12. This will cancel out the moles of PNCl2, leaving you with grams as the units. Now, all you have to do is multiply. 0.170*115.89 = 19.7 grams PNCl2 (rounded, again).
