How many oxygen atoms in a #300*g# mass of calcium carbonate?

1 Answer
Jun 8, 2016

Answer:

We work out (i) the molar quantity of #CaCO_3#, and (ii) the constituent quantity of oxygen.

Explanation:

#"Moles of calcium carbonate, "(300*g)/(100.09*g*mol^-1)# #~=# #3*mol#.

Given the elemental makeup, in such a quantity there are #3# moles of calcium, #3# moles of carbon, and #9# moles of oxygen.

But what is a mole? It is simply a LARGE number that relates to a given mass of stuff. In #1# #mol# of stuff there are #6.022xx10^23# individual particles of that stuff.

So given 3 moles of calcium carbonate, there are 3 moles of calcium, 3 moles ofcarbon, and 9 moles of oxygen atoms.

So #"number of oxygen atoms"# #=# #9*molxxN_A#

#=# #6.022xx10^23*mol^-1xx9*mol" oxygen atoms"# #=# #"oxygen atoms"??#

What is the mass of this quantity of oxygen atoms, and how do you know?

See here for another examples of this process.