Amixture contains only nacl and al2(so4)3. a 1.45-g sample of the mixture is dissolved in water, and an ex- cess of naoh is added, producing a precipitate of al(oh)3. the precipitate is filtered, dried, and weighed. the mass of the precipitate is 0.107 g. what is the mass percent of al2(so4)3 in the sample?

The mass percent of aluminum sulfate in the sample is 16.18%.

Explanation:

Mass of the sample = 1.45 g

Mass of the precipitate = 0.107 g

Moles of aluminum hydroxide =

According to reaction, 2 moles of aluminum hydroxide is obtained from 1 mole of aluminum sulfate .

Then 0.001372 moles of aluminum hydroxide will be obtained from:

Mass of 0.000686 moles of aluminum sulfate :

= 0.000686 mol × 342 g/mol = 0.2346 g

The mass percent of aluminum sulfate in the sample:

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

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