7.62g of Fe are allowed to react with 8.67g of S to form brown black iron(III) sulphide at high temp. what is the limiting reagent?
To determine the limiting reagent in a chemical reaction, we need to compare the moles of each reactant and see which one is present in lesser quantity.
First, we should calculate the number of moles for each substance. We can do this by dividing the mass of each substance by its molar mass.
The molar mass of Fe (iron) is approximately 55.85 g/mol, and the molar mass of S (sulphur) is approximately 32.06 g/mol.
Moles of Fe = mass of Fe / molar mass of Fe = 7.62 g / 55.85 g/mol
Moles of S = mass of S / molar mass of S = 8.67 g / 32.06 g/mol
Calculating moles:
Moles of Fe = 0.1363 mol
Moles of S = 0.2706 mol
Now, let's look at the balanced chemical equation for the reaction:
Fe + S → FeS
The stoichiometry of the reaction tells us that one mole of Fe reacts with one mole of S to form one mole of FeS.
From the balanced equation, we see that the mole ratio between Fe and FeS is 1:1. Therefore, if the moles of FeS formed are less than or equal to the moles of Fe, Fe is the limiting reagent. However, if the moles of FeS formed are less than the moles of S, S is the limiting reagent.
In this case, we can see that the moles of FeS formed (0.1363 mol) are equal to the moles of Fe (0.1363 mol), indicating that Fe is the limiting reagent.
To determine the limiting reagent in a chemical reaction, we need to compare the amount of reactants used and their respective molar masses. The reactant that produces the least number of moles of product will be the limiting reagent.
First, let's calculate the number of moles for each reactant:
Molar mass of Fe = 55.85 g/mol
Molar mass of S = 32.06 g/mol
Number of moles of Fe = 7.62 g / 55.85 g/mol
≈ 0.1363 mol
Number of moles of S = 8.67 g / 32.06 g/mol
≈ 0.2705 mol
Next, we need to determine the stoichiometry of the reaction, which is the balanced chemical equation. From the balanced equation, we can see the molar ratio between Fe and S in the reaction.
The balanced chemical equation for the reaction is:
3Fe + 4S → Fe3S4
From the balanced equation, we see that the molar ratio between Fe and S is 3:4. This means that for every 3 moles of Fe, we need 4 moles of S.
Now we can determine the limiting reagent. Since the ratio of Fe to S in the reaction is 3:4, we need 3/4 moles of Fe for each mole of S.
To determine the limiting reagent, we compare the actual moles used to the required moles based on the stoichiometry:
Required moles of Fe = 3/4 * 0.2705 mol
≈ 0.203 mol
Since the number of moles of Fe (0.1363 mol) is less than the required moles (0.203 mol) of Fe for the reaction, Fe is the limiting reagent.
Therefore, Fe is the limiting reagent in this reaction.