no. of ions in 100g of Na2SO4

Relative atomic masses: Na = 23.0, S = 32.1, O = 16.0
Avogadro constant: L = 6.02 x 1023 mol-1

Molar mass of Na2SO4 = 142.1 g mol-1

No. of moles of Na2SO4 = 100/142.1 mol

No. of formula units of Na2SO4 = (100/142.1) x (6.02 x 1023) formula units

Each formula unit of Na2SO4 contains 3 ions (2 Na+ and 1 SO42-).

No. of ions = (100/142.1) x (6.02 x 1023) x 3 = 1.27 x 1024 ions

No. of moles of Na2SO4 = 100
--------------------------- = 0.703729767g/mol
2(23) + (32.1) + 4(16)

No. of moles of ions of Na2SO4 = 0.703729769 * 3 = 2.111189303

No. of ions = 2.111189303 x L = 1.270935961 x 10^24

2009-08-14 15:37:55 補充：
個到係
100 / 2(23)+32.1+4(16)

yahoo個到tun左d格