Explanation: The formula unit of KCl is KCl itself. The molar mass of KCl is 74.5513 g/mol1. To calculate the number of formula units in 0.56 grams of KCl, we first need to convert grams to moles using the molar mass of KCl:
0.56 g KCl * (1 mol KCl / 74.5513 g) = 0.00751 mol KCl
Next, we can use Avogadro’s number (6.022 x 10^23) to convert moles to formula units:
0.00751 mol KCl * (6.022 x 10^23 formula units / 1 mol) = 4.52 x 10^21 formula units
Therefore, there are approximately 4.52 x 10^21 formula units in 0.56 grams of KCl.