How many silver atoms are there in a #0.566*kg# mass of silver?

1 Answer
Oct 9, 2016

Answer:

#0.566*kg# of silver #~=# #30xx10^23" silver atoms"#

Explanation:

We know (or should know) that the formula mass of silver is #107.87*g*mol^-1#. How did I know this? Did I know it off the top of my head? How will you know this if you are asked the question in an exam?

Now #1# #"mole"# of silver atoms or in a #107.87*g# mass, there are, by definition, #6.022xx10^23# #"individual atoms of silver."#

So all I have to do to get the number of silver atoms, is (i) calculate the molar quantity, and (ii) multiply this molar quantity by #6.022xx10^23*mol^-1#, i.e. #"Avogadro's number"#.

So.......

#(0.566xx10^3*g)/(107.87*g*mol^-1)# #=# #5.25*mol#.

And #5.25*molxx6.022xx10^23*mol^-1# #~=# #30xx10^23" silver atoms"#