Question

Can you please help post lab question..

DATA AND CALCULATIONS

Absorbance	Trial 1 0.039		Trial 2 0.045		Trial 3 0.063		Trial 4 0.086
Absorbance of standard (Trial 5)		0.792		Temperature		25°C

K_c expression K_c =

[Fe³⁺]i

Trial 1

Trial 2

Trial 3

Trial 4

[SCN^–]_i

[FeSCN²⁺]_eq

[Fe³⁺]_eq

[SCN^–]_eq

K_c value

Average of K_c values

Kc = ________________________ at ___25_____°C

	beaker	Fe(NO3)3 (mL)	KSCN (mL)	H2O (mL)
	1	5	2	93
	2	5	3	92
	3	5	4	91
	4	5	5	90

PROCESSING THE DATA
1. Write the Kc expression for the reaction in the Data and Calculation table.
2. Calculate the initial concentration of Fe3+, based on the dilution that results from addingKSCN solution and water to the original 0.0020 M Fe(NO3)3 solution. See Step 2 of theprocedure for the volume of each substance used in Trials 1-4. Calculate [Fe3+]i using theequation:

[Fe3+]i =

Fe(NO3)3 mLtotal mL X (0.0020 M)

This should be the same for all four test tubes.
3. Calculate the initial concentration of SCN–, based on its dilution by Fe(NO3)3 and water:

[SCN–]i =

KSCN mLtotal mL X (0.0020 M)

In beaker 1, [SCN–]i = (2 mL / 100 mL)(.0020 M) = .000040 M. Calculate this for the otherthree beakers.
4. [FeSCN2+]eq is calculated using the formula:

[FeSCN2+]eq =

AeqAstd

X [FeSCN2+]std

where Aeq and Astd are the absorbance values for the equilibrium and standard solutions,
respectively, and [FeSCN2+]std = (1/100)(0.0020) = 0.000020 M. Calculate [FeSCN2+]eq foreach of the four trials.
5. [Fe3+]eq: Calculate the concentration of Fe3+ at equilibrium for Trials 1-4 using the equation:

[Fe3+]eq = [Fe3+]i – [FeSCN2+]eq

6. [SCN–]eq: Calculate the concentration of SCN- at equilibrium for Trials 1-4 using theequation:

[SCN–]eq = [SCN–]i – [FeSCN2+]eq

7. Calculate Kc for Trials 1-4. Be sure to show the Kc expression and the values substituted infor each of these calculations.
8. Using your four calculated Kc values, determine an average value for Kc.