Answer:
5.83 mol.
Explanation:
- From the balanced reaction:
<em>2Al + 3Ag₂S → 6Ag + Al₂S₃,</em>
It is clear that 2 mol of Al react with 3 mol of Ag₂S to produce 1 mol of Ag and 1 mol of Al₂S₃.
Al reacts with Ag₂S with (2: 3) molar ratio.
<em>So, 2.27 mol of Al reacts completely with 3.4 mol of Ag₂S with (2: 3) molar ratio.</em>
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- The limiting reactant is Ag₂S.
- The excess "left over" reactant is Al.
The reamining moles of excess reactant "Al" = 8.1 mol - 2.27 mol = 5.83 mol.
Multiplying the subscripts within the empirical formula by this number gives you the molecular formula H2O2.
Answer:
C₆H₈O₆
Explanation:
First off, the<u> percent of oxygen by mass</u> of vitamin C is:
- 100 - (40.9+4.58) = 54.52 %
<em>Assume we have one mol of vitamin C</em>. Then we would have <em>180 grams</em>, of which:
- 180 * 40.9/100 = 73.62 grams are of Carbon
- 180 * 4.58/100 = 8.224 grams are of Hydrogen
- 180 * 54.52/100 = 98.136 grams are of Oxygen
Now we <u>convert each of those masses to moles</u>, using the <em>elements' respective atomic mass</em>:
- C ⇒ 73.62 g ÷ 12 g/mol = 6.135 mol C ≅ 6 mol C
- H ⇒ 8.224 g ÷ 1 g/mol = 8.224 mol H ≅ 8 mol H
- O ⇒ 98.136 g ÷ 16 g/mol = 6.134 mol O ≅ 6 mol O
So the molecular formula for vitamin C is C₆H₈O₆
