how do u find number of moles in 25 grams of HF

Question

anonymous · Answer

1.25 moles

alphadxg · Answer

@Night-Watcher lets show him how to get that answer.

When we need to find moles, we need to convert them using units.
So we are given 25 grams of HF, now to convert grams to moles, we need to find a way to cancel out grams.

Well, if we set up the equation we would have grams on the top, and then we have to have grams on the bottom, then this will cancel out, leaving us with the unit moles.

So we have to since we need to put grams on the bottom, where do we get our other gram unit? Well since we are dealing with HF, we need to find what the molar mass is to get to moles.
Looking at the periodic table 

H = 1.008 grams
F = 18.998 grams

HF = 20.006|dw:1401373104242:dw|