Respuesta :
Answer : The limiting reagent in this reaction is, [tex]Al_2(SO_4)_3[/tex] and number of moles of excess reagent is, 1.69 moles
Explanation : Given,
Mass of [tex]Al_2(SO_4)_3[/tex] = 500.0 g
Mass of [tex]Ca(OH)_2[/tex] = 450.0 g
Molar mass of [tex]Al_2(SO_4)_3[/tex] = 342.15 g/mol
Molar mass of [tex]Ca(OH)_2[/tex] = 74.1 g/mol
First we have to calculate the moles of [tex]Al_2(SO_4)_3[/tex] and [tex]Ca(OH)_2[/tex].
[tex]\text{Moles of }Al_2(SO_4)_3=\frac{\text{Given mass }Al_2(SO_4)_3}{\text{Molar mass }Al_2(SO_4)_3}[/tex]
[tex]\text{Moles of }Al_2(SO_4)_3=\frac{500.0g}{342.15g/mol}=1.461mol[/tex]
and,
[tex]\text{Moles of }Ca(OH)_2=\frac{\text{Given mass }Ca(OH)_2}{\text{Molar mass }Ca(OH)_2}[/tex]
[tex]\text{Moles of }Ca(OH)_2=\frac{450.0g}{74.1g/mol}=6.073mol[/tex]
Now we have to calculate the limiting and excess reagent.
The given chemical reaction is:
[tex]Al_2(SO_4)_3(aq)+3Ca(OH)_2(aq)\rightarrow 2Al(OH)_3(s)+3CaSO_4(s)[/tex]
From the balanced reaction we conclude that
As, 1 mole of [tex]Al_2(SO_4)_3[/tex] react with 3 mole of [tex]Ca(OH)_2[/tex]
So, 1.461 moles of [tex]Al_2(SO_4)_3[/tex] react with [tex]1.461\times 3=4.383[/tex] moles of [tex]Ca(OH)_2[/tex]
From this we conclude that, [tex]Ca(OH)_2[/tex] is an excess reagent because the given moles are greater than the required moles and [tex]Al_2(SO_4)_3[/tex] is a limiting reagent and it limits the formation of product.
Number of moles of excess reagent = 6.073 - 4.383 = 1.69 moles
Therefore, the limiting reagent in this reaction is, [tex]Al_2(SO_4)_3[/tex] and number of moles of excess reagent is, 1.69 moles