Some chemicals, most often inorganic salts, in the laboratory have the nasty tendency to absorb water from the atmosphere. This property is called hygroscopicity. Anhydrous (water-free) Cupric Perchlorate [Cu (ClO4)2] weighs 262.447g/mol, but after sitting on out on the bench top absorbs water from the air and now weighs 370.540g/mol. How many water molecules did our Cupric Perchlorate absorb?

If an anhydrous Cupric Perchlorate weighs 262.447g/mol initially and weighs 370.540 g/mol after sitting on the bench to absorb water from the air, the number of water molecules absorbed would be 6 moles.

First, let us calculate the amount of water gained during the course of staying on the bench:

Water gained = weight after gaining water - initial weight

= 370.540 - 262.447

= 108.093g/mole

The total amount of water gained per mol is 108.093. Each water molecule weighs 18.015 g/mole. Thus, the total number of water molecules that will sum up to 108.093 would be:

108.093/18.015 = 6 moles

In other words, the number of water molecules absorbed by the Cupric Perchlorate is 6 moles.

More on calculating water of hydration can be found here: https://brainly.com/question/919417