given the reactant amounts specified in each chemical eguation, determine the limiting reactant in each case:
a. HCL+NaOH->NaCl+H2O
2.0 mole of HCl
2.5 mole NaOH
b. Zn+2HCl->ZnCl2+H2
2.5 mole Zn
6.o mole HCl
c. 2Fe(OH)3+3H2SO4->Fe2(SO4)3+6H2O
4.0 mole Fe(OH)3
6.5 mole H2SO4
Here is a detailed answer about limiting reagent problems I gave to Tony further up the page.
http://www.jiskha.com/display.cgi?id=1267661890
To determine the limiting reactant, you need to compare the amounts of each reactant to the stoichiometric ratio in the balanced chemical equation.
a. HCl + NaOH -> NaCl + H2O
The balanced chemical equation tells us that the stoichiometric ratio between HCl and NaOH is 1:1. This means that for every 1 mole of HCl, we need 1 mole of NaOH.
Given:
2.0 moles of HCl
2.5 moles of NaOH
Since the stoichiometric ratio is 1:1, the limiting reactant is determined by the reactant with the lesser number of moles. In this case, HCl has 2.0 moles and NaOH has 2.5 moles. Therefore, the limiting reactant is HCl.
b. Zn + 2HCl -> ZnCl2 + H2
The balanced chemical equation tells us that the stoichiometric ratio between Zn and HCl is 1:2. This means that for every 1 mole of Zn, we need 2 moles of HCl.
Given:
2.5 moles of Zn
6.0 moles of HCl
To determine the limiting reactant, we need to compare the moles of Zn to the stoichiometric ratio. Since the stoichiometric ratio is 1:2, we need 2 moles of HCl for every 1 mole of Zn.
Based on the given amounts, we have 2.5 moles of Zn and 6.0 moles of HCl.
Step 1: Calculate the moles of HCl required for the given amount of Zn:
2.5 moles Zn x (2 moles HCl / 1 mole Zn) = 5.0 moles HCl (equivalent amount if all the Zn reacted)
Step 2: Compare the calculated moles of HCl to the actual amount of HCl:
5.0 moles of HCl calculated (from Zn) < 6.0 moles of HCl given
Since the calculated amount from the Zn is less than the amount of HCl given, the limiting reactant is Zn.
c. 2Fe(OH)3 + 3H2SO4 -> Fe2(SO4)3 + 6H2O
The balanced chemical equation tells us that the stoichiometric ratio between Fe(OH)3 and H2SO4 is 2:3. This means that for every 2 moles of Fe(OH)3, we need 3 moles of H2SO4.
Given:
4.0 moles of Fe(OH)3
6.5 moles of H2SO4
To determine the limiting reactant, we need to compare the moles of Fe(OH)3 to the stoichiometric ratio. Since the stoichiometric ratio is 2:3, we need 3 moles of H2SO4 for every 2 moles of Fe(OH)3.
Based on the given amounts, we have 4.0 moles of Fe(OH)3 and 6.5 moles of H2SO4.
Step 1: Calculate the moles of H2SO4 required for the given amount of Fe(OH)3:
4.0 moles Fe(OH)3 x (3 moles H2SO4 / 2 moles Fe(OH)3) = 6.0 moles H2SO4 (equivalent amount if all the Fe(OH)3 reacted)
Step 2: Compare the calculated moles of H2SO4 to the actual amount of H2SO4:
6.0 moles of H2SO4 calculated (from Fe(OH)3) < 6.5 moles of H2SO4 given
Since the calculated amount from the Fe(OH)3 is less than the amount of H2SO4 given, the limiting reactant is Fe(OH)3.
To determine the limiting reactant in each case, we need to compare the moles of the reactants and see which one is present in the least amount. The reactant that is completely consumed will be the limiting reactant.
a. HCl + NaOH -> NaCl + H2O
2.0 moles of HCl
2.5 moles of NaOH
To determine the limiting reactant, we can compare the stoichiometric ratio of HCl to NaOH in the balanced equation. The ratio is 1:1, which means that for every one mole of HCl, we need one mole of NaOH.
Therefore, since we have 2.0 moles of HCl and 2.5 moles of NaOH, HCl is the limiting reactant because it is present in the least amount.
b. Zn + 2HCl -> ZnCl2 + H2
2.5 moles of Zn
6.0 moles of HCl
Again, we can compare the stoichiometric ratio of Zn to HCl in the balanced equation. The ratio is 1:2, which means that for every one mole of Zn, we need two moles of HCl.
Since we have 2.5 moles of Zn and 6.0 moles of HCl, we need 5.0 moles of HCl to react with all the Zn. However, we only have 6.0 moles of HCl, which is more than enough. Therefore, Zn is the limiting reactant because it is present in the least amount.
c. 2Fe(OH)3 + 3H2SO4 -> Fe2(SO4)3 + 6H2O
4.0 moles of Fe(OH)3
6.5 moles of H2SO4
Again, we need to compare the stoichiometric ratio of Fe(OH)3 to H2SO4 in the balanced equation. The ratio is 2:3, which means that for every two moles of Fe(OH)3, we need three moles of H2SO4.
Since we have 4.0 moles of Fe(OH)3 and 6.5 moles of H2SO4, we need 6.0 moles of H2SO4 to react with all the Fe(OH)3. However, we only have 6.5 moles of H2SO4, which is more than enough. Therefore, Fe(OH)3 is the limiting reactant because it is present in the least amount.