8. A hydrate is an ionic substance where water has been included in its matrix. The
hydrate is not a liquid, but a solid. A nickel(II) sulfate hydrate has the formula: NiSO4 •xH2O where "x" is a whole number representing the molecules of H2O present for every Ni^2+ and SO4^2- ion.
a. If 2.117 g of the hydrate is heated to drive the water away, and the resulting product wights 1.246 g, what is the percent mass of water in the hydrate?
b. How many moles of water are in 2.117 g of the hydrate?
c. How many moles of NiSO4 are in 2.117 g of the hydrate
d. How many moles of water are present per mole of NiSO4.
e. What is the formula for the hydrate?
Hard titration chemistry questions. Please help!?
2017-10-16 4:28 pm
回答 (2)
2017-10-16 7:22 pm
✔ 最佳答案
8.a.
Mass of H₂O in 2.117 g of NiSO₄•xH₂O = (2.117 - 1.246) g = 0.871 g
Percent mass of H₂O in NiSO₄•xH₂O = (0.871/2.117) × 100% = 41.1%
b.
Molar mass of H₂O = (1.0×2 + 16.0) g/mol = 18.0 g/mol
No. of moles of H₂O in 2.117 g of NiSO₄•xH₂O = (0.871 g) / (18.0 g/mol) = 0.0484 mol
c.
Molar mass of NiSO₄ = (58.7 + 32.1 + 16.0×4) g/mol = 154.8 g/mol
No. of moles of NiSO₄ in 2.117 g of NiSO₄•xH₂O = (1.246 g) / (154.8 g/mol) = 0.008049 mol
d.
No. of moles of H₂O present per mole of NiSO₄ = (0.0484 mol) / (0.008049) = 6.01 ≈ 6
e.
Formula of the hydrate = NiSO₄•6H₂O
2017-10-16 4:34 pm
a: x-y=z..... z/x*100 = percent water
b: mass of 1 mole H2O=18g....z/18
c: similarly, calculate NiSO4, divide 1.246 by that
b: mass of 1 mole H2O=18g....z/18
c: similarly, calculate NiSO4, divide 1.246 by that
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