Question

Given the following chemical reaction equation:

3 Mg (s) + Al2O3 (s)------> 3 MgO (s) + 2 Al (s)
and 144g of MG and 150g of Al2O3 are reacted.

which chemical compound is the limiting reactant compound?
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Answer 1

Al₂O₃ is the limiting reactant

Step-by-step explanation:

The limiting reagent or limiting reactant in a chemical reaction is a reactant that is totally used up when the chemical reaction is completed and subsequently, the reaction stops as no more products can be formed from the excess reactant.

Equation of the the reaction reaction is given below:

3 Mg (s) + Al₂O₃ (s) ----> 3 MgO (s) + 2 Al (s)

Mole ratio of reactants from the equation shows that 3 moles of magnesium metal is required to react with 1 mole of aluminum oxide.

Molar mass of magnesium metal, Mg = 24 g/mol

Molar mass of aluminum oxide, Al₂O₃ = (27 * 2 + 16 * 3) = 102 g/mol

from the equation of reaction, (24 * 3 g) 72 g of Mg reacts with 102 g of Al₂O₃

Given masses of reactants:

144 g of Mg = 144/24 6 moles of Mg

150 g of Al₂O₃ = 1.47 moles of Al₂O₃

Mole ratio of Mg to Al₂O₃ = 6/1.47 = 4.08 : 1

Therefore, magnesium is excess reactant while Al₂O₃ is the limiting reactant