How many moles of licl are in 250g of licl

Moles are amount of substance. Molar mass is the mass of 1 mol of substance. 
Molar mass of LiCl is the sum of molar masses of the individual elements. 
molar mass of Li - 6.9 g/mol and Cl - 35.45 g/mol 
molar mass of LiCl - 6.9 + 35.45 = 42.35 
therefore molar mass of LiCl - 42.35 g/mol 
number of moles of LiCl = mass present / molar mass of LiCl
number of LiCl moles = 250 g / 42.35 g/mol = 5.90 mol 
5.90 moles of LiCl