m (Al) = 48 g.
Determine the mass of aluminum oxide. We write down the equation of reactions.
4Al + 3O2 = 2Al2O3.
We find the amount of aluminum substance, for this we use the following formula.
n = m / M.
Where n is the amount of substance.
m is the mass of the substance.
M is the molar mass of the substance.
M (Al) = 27 g / mol.
n = 48 g / 27 g / mol = 1.7 mol.
Further, according to the reaction equation, we find the amount of the substance of aluminum oxide.
1.7 mol Al – х mol Al2O3.
4 mol Al – 2 mol Al2O3.
X = 1.7 mol × 2 mol ÷ 4 mol = 0.85 mol.
Next, we find the mass of aluminum.
M (Al2O3) = 27 × 2 + 16 × 3 = 102 g / mol.
m = n × M = 0.85 mol × 102 g / mol = 86.7 g.
Answer: m (Al2O3) = 86.7 g.
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