How many moles of potassium chloride are there in 50 grams?

For this you need the atomic (molecular) mass of KCl. Take the number of grams and divide it by the atomic mass. Multiply by one mole for units to cancel. KCl= 74.6 grams

50.0 grams KCl / (74.6 grams) = .670 moles KCl