# How to find the limiting reactant?

Submitted by kko2 on Thu, 05/02/2013 - 22:53

2Al + NiCl2 ----> 2AlCl +Ni

a. If 2.50 mol of each reactant are used in the reaction, which is the limiting reagent?
b. If 2.50 mol of each reactant are used in the reaction, then how many mokles of each    product are obtained?
c. If 2.50 mol of each reactant are used in the reaction, then how many moles of excess reagent are left unreacted?
d. If 2.00 g of each reactant are used in the reaction, which is the limiting reagent/
e. If 2.00 g of each reactant are used in the reaction, then how many grams of each product are obtained?
f. If 2.00 g of each reactant are use in the reaction, then how many grams of excess reagent are left unreacted?

(I have no clue how to do this and I need clear step by step intsructions. please help)

first of all in this reaction in not correct you cannot make AlCl as Al carries +3 charge the correct product should be AlCl3 , so then your reaction should look like this

2Al + 6NiCl2 ----> 2AlCl3 + 6Ni

a ) 2 moles of Al is producing  1 mole of Ni , so 2.5 mol of Al will produce ,how many moles of Ni, this you can find like this

2.50 mol Al x  6 mol Ni / 2 mol Al  = 7.5 mole of Ni

similary for NiCl2

2.50 mol of NiCl2  x  6 mol Ni / 6  mol NiCl2 = 2.5 mol of Ni

the limiting reactant is one that produce lower moles of the product and as NiCl2 is produing 1 mole of Ni,it is limiting reactant .

b. the amount of product formed in a reaction is that limiting reaction forms . so 2.5 mol of Ni are obtained and moles of AlCl3 can be found using the equation;

2.5 mol NiCl2 x 2 mol AlCl3 / 6 mol NiCl2 = 0.83 mol of AlCl3

c. 2.5 mol NiCl2  x 2 mol Al / 6 mol NiCl2 = 0.83 mol of Al actually reacted with NiCl2  and we had 2.5 mol of Al which means that 2.5 - 0.83 = 1.67 mol of Al is in excess.

d. If 2.00 g of each reactant are used in the reaction, which is the limiting reagent/
e. If 2.00 g of each reactant are used in the reaction, then how many grams of each product are obtained?
f. If 2.00 g of each reactant are use in the reaction, then how many grams of excess reagent are left unreacted?

all these parts are similar to other parts ,you can try to solve them by youraself.

ok ok sweet. thanks! but how do you do the rest im stuck. :(