How many formula units of CuCl_2CuCl2 are present in a 12.53*g12.53g mass of the salt?

1 Answer
Feb 15, 2018

Well what is the formula mass of cupric chloride....?

Explanation:

The anhydrous salt has a formula mass of 134.45* g*mol^-1 134.45gmol1. How did I get this?

And so we take the QUOTIENT...."mass"/"formula mass"massformula mass...

...(12.53*cancelg)/(134.45* cancelg*mol^-1)=0.0932*mol

And so how does this molar quantity help us? Well we know that BY DEFINITION one mole specifies "Avogadro's number" of formula units....where .........

N_A-="Avocado number"=6.022xx10^23*mol^-1

And so we take the product...

"molar quantity"xx"Avogadro's number"

0.0932*molxx6.022xx10^23*mol^-1-=5.62xx10^22*"formula units"

...and we are careful to speak of "formula units" of CuCl_2. How many copper atoms, and how many chlorine atoms are in this quantity?