Question

2. What is the percent sulfur in iron (III) sulfate?

Answer 1

Step 1

The chemical formula of iron (III) sulfate is the next one:

Fe2(SO4)3

As we can see, there are 3 x 1 atom of S, 3 atoms of S

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Step 2

Information needed:

The atomic masses of:

Fe) 55.8 g/mol

S) 32.0 g/mol

O) 16.0 g/mol

(Please, the periodic table is useful here)

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Step 3

The % of S in Fe2(SO4)3 is calculated as follows:

`\frac{3\text{ x 32.0 g/mol of S}}{(2\text{ x 55.8 g/mol Fe + 3 x 32.0 g/mol S + 3 x 4 x 16.0 g/mol O\rparen}}x100\text{ = 24.0 \%}`

Answer: 24 % of S