A standard solution of FeSCN2+ is prepared by combining 9.00 mL of 0.200 M Fe(NO3)3 w/1.00 mL of 0.0020 M KSCN. The equilibrium concentration of FeSCN2+ ([FeSCN2+]std) for this standard solution is assumed to be__?__M
0.002 x 1/10 = ??
To determine the equilibrium concentration of FeSCN2+ ([FeSCN2+]std) for the standard solution, we can use the principles of stoichiometry and equilibrium. Let's go step by step.
1. First, let's determine the moles of Fe(NO3)3 and KSCN used in the standard solution.
Moles of Fe(NO3)3 = volume of Fe(NO3)3 solution (in L) x concentration of Fe(NO3)3 (in M)
= 9.00 mL x (1 L/1000 mL) x 0.200 M
= 0.0018 moles
Moles of KSCN = volume of KSCN solution (in L) x concentration of KSCN (in M)
= 1.00 mL x (1 L/1000 mL) x 0.0020 M
= 0.000002 moles
2. Now, let's determine the limiting reactant. The reactant that is completely consumed determines the amount of product formed. In this case, the limiting reactant is the one that produces the least amount of product.
To find the limiting reactant, we compare the moles of Fe(NO3)3 and KSCN. Since the molar ratio between Fe(NO3)3 and FeSCN2+ is 1:1 and the molar ratio between KSCN and FeSCN2+ is 1:1, the limiting reactant will be determined by the smallest number of moles.
Here, KSCN has fewer moles (0.000002 moles) compared to Fe(NO3)3 (0.0018 moles), so it is the limiting reactant.
3. Next, we need to determine the moles of FeSCN2+ formed using the limiting reactant.
Moles of FeSCN2+ = moles of limiting reactant (KSCN) = 0.000002 moles
4. Finally, let's determine the equilibrium concentration of FeSCN2+ ([FeSCN2+]std).
Equilibrium concentration (in M) = moles of FeSCN2+ / total volume of the solution (in L)
= 0.000002 moles / (9.00 mL + 1.00 mL) x (1 L/1000 mL)
= 2.0 x 10^-7 M
Therefore, the equilibrium concentration of FeSCN2+ ([FeSCN2+]std) for this standard solution is 2.0 x 10^-7 M.