How many moles of pottasium are in 125g of KCl?

The formula given shows that each formula unit of KCl contains one atom of potassium. Therefore, the number of moles of potassium will be the same as the number of moles of KCl, and its gram formula mass is 74.55. therefore, the number of moles is 125/74.55 or 1.68, to the justified number of significant digits.