mole concept

Question

When 9.0 g of aluminium reacts completely with oxygen, how many grams of Al2O3 are formed? (2Al + 3/2 O2 → Al2O3, M(Al)=27, M(Al2O3)=102)

RankGuru · Accepted Answer

1. **Reaction Stoichiometry**: $2 \ Al + \frac{3}{2} \ O_2 	o Al_2O_3$.
   - $2 \ mol \ Al 	o 1 \ mol \ Al_2O_3$.
2. **Find Moles of $Al$**:
   - $n_{Al} = \frac{9.0}{27} = \frac{1}{3} \ mol$.
3. **Find Moles of $Al_2O_3$ produced**:
   - $n_{yield} = \frac{1}{2} 	imes \frac{1}{3} = \frac{1}{6} \ mol$.
4. **Calculate Mass**:
   - $Mass = \frac{1}{6} 	imes 102 \ g/mol = 17 \ g$.

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