What is the number of representative particles in .400 mol #KCl#?

1 Answer
Apr 1, 2016

Answer:

There are #0.4# #xx# #N_A# potassium cations, and an equal quantity of chloride anions.

Explanation:

But what is #N_A#? #N_A# is simply #"Avogadro's number"#, #6.022140857 × 10^23#. This number has the property that #N_A# #""^12C# atoms has a mass of #12.00# #g# precisely. #N_A# is thus the link between atoms and molecules, about which we can only conceive, and the macro world of grams and kilograms, and litres, that which we can measure in a laboratory.

What is the mass of #0.400# #mol# #KCl#, given that #KCl# has a mass of #74.55*g*mol^-1#?