Mole Calculation

2007-01-29 1:49 am

In 67.5g of hydrated aluminium sulphate Al 2(SO4)3* 6 H2O, calculate

- the no. of moles of aluminium ions, Al 3+;
- the no. of moles of water molecules;
- the no. of sulphur atoms;
- the no. of oxygen atoms; and
- the no. of ions.

回答 (1)

用戶80089

2007-01-29 2:12 am

✔ 最佳答案

mass no. Al=27.0 S=32.1 O=16.0 H=1.0
Avogadro constant = L = 6.02*10^23
formula mass of hydrated aluminium sulphate=27*2+(32.1+16*4)*3+6*(1*2+16)=450.3
no. of moles in sample = 67.5/450.3 = 0.15 mole

- the no. of moles of aluminium ions, Al 3+; (= 0.15*2=0.30mole)
- the no. of moles of water molecules;(=0.15*6=0.90mole)
- the no. of sulphur atoms;(=0.15*3*L=0.45*L=2.71*10^23 atoms)
- the no. of oxygen atoms; and(=0.15*(3*4+6)*L=2.70*L=1.62432*10^24 atoms)
- the no. of ions. (=0.15*(2+3)*L=0.75*L=4.512*10^23 atoms)

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