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a) The rate of formation of C in the reaction A + 3B 3C + 2D is 1.5 mol/L/s. Sta

ID: 701163 • Letter: A

Question

a) The rate of formation of C in the reaction A + 3B 3C + 2D is 1.5 mol/L/s. State the rates of formation or consumption of A, B, and D b) The stoichiometry of a particular liquid phase reaction is represented by 3A + 2B C 5D. The initial concentration of A and B are 2 mol/L before any product has formed. If at some time, the concentration of D is 1.5 mol/L, what is the concentration of the other species? of econcentraton of the others Rae c) Using the same initial concentrations as in part b), what will the concentration of all the species be if XA 0.4?

Explanation / Answer

Part a

A + 3B = 3C + 2D

Rate of formation of C

rC = 1.5 mol/L/s

Relation between the rate of species for the given reaction

-rA/1 = - rB/3 = rC/3 = rD/2

Rate of consumption of A = - rC/3 = - 1.5/3 = - 0.5 mol/L/s

Rate of consumption of B = - rC = - 1.5 mol/L/s

Negative sign shows thebRate of consumption of species

Rate of formation of D = 2* rC/3 = 2*1.5/3 = 1 mol/L/s

Part b

Initial concentration of A

CA0 = 2 mol/L

Initial concentration of B

CB0 = 2 mol/L

CC0 = CD0 = 0

After some time

Concentration of D, CD = 1.5 mol/L

Reaction 3A + 2B = C + 5D

Lets assume the conversion of A = XA

CD = CD0 + (5/3)*CA0*XA

1.5 = 0 + (5/3)*2*XA

XA = 0.45

Final concentration of C

CC = CC0 + (1/3)*CA0*XA

= 0 + (1/3)*2*0.45 = 0.3 mol/L

Final concentration of A

CA = CA0(1-XA)

= 2(1-0.45) = 1.1 mol/L

Final concentration of B

CB = CB0 - (2/3)*CA0*XA

= 2 - (2/3)*2*0.45 = 1.40 mol/L

Part C

CA0 = CB0 = 2 mol/L

XA = 0.4

Final concentration of A

CA = CA0(1-XA)

= 2(1-0.4) = 1.2 mol/L

Final concentration of B

CB = CB0 - (2/3)*CA0*XA

= 2 - (2/3)*2*0.4 = 1.467 mol/L

Final concentration of C

CC = CC0 + (1/3)*CA0*XA

= 0 + (1/3)*2*0.4 = 0.267 mol/L

Final concentration of D

CD = CD0 + (5/3)*CA0*XA

= 0 + (5/3)*2*0.4 = 1.333 mol/L