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1. Aluminum can be determined gravimetrically by reaction with a solution of 8-h

ID: 853705 • Letter: 1

Question

1.

Aluminum can be determined gravimetrically by reaction with a solution of 8-hydroxyquinoline (C9H7NO). The net ionic equation is:

Al3++ 3C9H7NO ? Al(C9H6NO)3 + 3H+

A mass of 18.29 g of Al(C9H6NO)3 (459.45 g/mol) was obtained by precipitating all of the Al3+ from a solution prepared by dissolving 4.91 g of a mineral. What is the mass percent of aluminum (26.98 g/mol) in the mineral sample?

## Give your answer to THREE decimal places ##

2.

A sample of Fungicide Copper (ll) Sulfate pentahydrate, CuSO4

Explanation / Answer

1)

Al3++ 3C9H7NO ? Al(C9H6NO)3 + 3H+

22.08 g X (1mole / 459.45 g) X (26.98 g Al / mole) = 1.296g Al
(1.296g / 4.14g) X 100 = 31.31% Al << answer

2)CuSO4 + BaCl2 ? BaSO4 + CuCl2

(2.324g BaSO4) / (233.43 g BaSO4/mol) x (1 mol CuSO4 / 1 mol BaSO4) x (249.68 g CuSO4