A3B9 represents a molecular formula. The representation of the empirical formula for this compound is AB3. This is so because the empirical formula is the simplest ratio of the atoms present in the molecule. You get AB3 when you divide the subscripts of A3B9, this is 3 and 9, by the greatest common factor, which is 3. 3/3 = 1 and 9/3 = 3, so the subscripts for the empirical formula are 1 and 3, which is what AB3 represents. <span>Answer: AB3.</span>
MAl₂(SO₄)₃·xH₂O:
(mAl×2) + (mS×3) + (mO×12) + (mH₂O×x)
(27×2)+(32×3)+(16×12)+(x×18) = 342 + 18x [g]
mAl₂: 27×2 = 54 [g]
54g ---------- 13,63%
342+18x ---- 100%
0,1363(342+18x) = 54
46,6146 + 2,4534x = 54
2,4534x = 7,3854
x ≈ 3
>>> Al₂(SO₄)₃·3H₂O <<<<
:)
The formula for the self ionization of water is 2H₂O(l)⇄H₃O⁺(aq)+OH⁻(aq)
The hydronium (H₃O⁺) is usually just referred to as a hydrogen ion or a proton (H⁺) and hydroxide (OH⁻) doesn't have another name that I am aware of. These ions do stay in solution. However the concentrations are really small and the equilibrium constant (K(w)) is 1×10⁻¹⁴.
I hope this helps. Let me know if anything is unclear.
