chemistry-question about mole

No. of mole of Na : No. ofmole of NaNO3 = 1 : 1, why ?

NaNO3 is an ionic compound.
1 formula unit of NaNO3 contain 1 Na⁺ ion and 1 NO3⁻ ion.
1 mole of NaNO3 consists of 1 mole of Na⁺ ions and 1 mole of NO3⁻ ions.
Hence, no. of moles of Na⁺ ions : No. of moles ofNaNO3 = 1 : 1


1.200g of a compoundcontaining only carbon, hydrogen and oxygen gave1.173 g of CO2 and 0.240g of H2O on complete combustion. Find the empirical formulaof the compound.

Molar mass of CO2 = 12 + 16x2 = 44 g/mol
Molar mass of H2O = 1x2 + 16 = 18 g/mol

In 1.200 g of the compound :
Mass of C = Mass of C in CO2 = 1.173 x (12/44) = 0.320 g
Mass of H = Mass of H in H2O = 0.240 x (1x2/18) = 0.0267 g
Mass of O = 1.200 - (0.320 + 0.0267) = 0.853

Mole ratio C : H : O
= 0.320/12 : 0.0267/1 : 0.853/16
= 0.0267 : 0.0267 : 0.0533
≈ 1 : 1 : 2

Empirical formula = CHO2

there is one Na ion in each NaNO3
ie: 1 Na ion+ 1 (NO3) ion=1 NaNO3
so no. of mole of Na : No. of mole of NaNO3=1:1