Question

calculate the number of ions number of oxygen atoms, total charge in 3g of (co₃)²

Answer 1

The molar mass of carbonate ions is 60 g per mole.
This means mass of 1 mole of carbonate ions = 60 g
Number of moles is given by
Number of mole = Given mass / molar mass
Given mass = 3g
Number of moles = 3/ 60
= 0.05 mol
We known 1 mol = 6.022 $\times$ 10²³
Therefore number of ions in 3 g = 0.05$\times$ 6.022 $\times$ 10²³
= 0.3011 $\times$ 10²³
As 1 carbonate ions contains 3 oxygen atom and 1 carbon atom, therefore
Number of carbon atom = 0.3011 $\times$ 10²³
Number of oxygen atom = 3 $\times$ 0.3011 $\times$ 10²³
= 0.9033 $\times$ 10²³
As the total charge on carbonate ion = -2
Therefore, total charge on 3g of carbonate ions = (-2)$\times$ 0.3011 $\times$ 10²³
= - 0.6022 $\times$ 1023
Here - sign indicates negative charge.