Question

Question #3a4ee

Answer 1

Well let's see.....I make it.....

`3.23xx10^-2*molxx6.022xx10^23*mol^-1xx32*"electrons"=?`

Explanation:

We somehow have got a mass of `2*g` nitrate ion, `NO_3^-`. We look at our Periodic Table, and we find that nitrogen `Z=7`, has 7 electrons, and oxygen, `Z=8`, has 8 electrons.

So per formula unit of `NO_3^-`, there are `7+3xx8+1=32*"electrons"`. Why did I add an extra electron.

Now we have a molar quantity of `(2*g)/(62.01*g*mol^-1)=3.23xx10^-2*mol`

And so there are `3.23xx10^-2*molxx6.022xx10^23*mol^-1xx32*"electrons"=?`

But hang on, `Z` specifies the number of protons in the nucleus. How can I use `Z` to define the number of electrons?