1. Tutorial 3 solutions Lecturer: Miss Anis Atikah Ahmad
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2. Questions
Write the rate laws for the following reactions assuming each reaction follows an elementary rate laws.
C2H6 → C2H4 + H2
(CH3)3COOC(CH3)3 ⇌ C2H6 + 2CH3COCH3
Write the rate law for the reaction:
2A + B → C
if the reaction
is second order in B and overall third order,
is zero order in A and first order in B
is zero order in both A and B
is first order in A and overall zero order

3. The formation of ortho-nitroaniline is formed from the reaction of ortho-nitrochlorobenzene (ONCB) and aqueous ammonia.
The liquid-phase reaction is first order in both ONCB and ammonia with k= m3/kmol-min at 188°C with E = 11,273 cal/mol. The initial entering concentration of ONCB and ammonia are 1.8 kmol/m3 and 6.6 kmol/m3 respectively.
Write the rate law for the rate of disappearance of ONCB in terms of concentration.
Set up stoichiometric table for this reaction for a flow system.
Explain how part (a) and (b) would be different for a batch system.
Write –rA solely as a function of conversion.
What is the initial rate of reaction (X=0) at 188°C and at 25°C?
What is the rate of reaction when X = 0.9 at 188°C and at 25°C?
What would be the corresponding CSTR volume at 25°C to achieve 90% conversion at 188°C for a feed rate of 2 dm3/min

4. Question (1)
Write the rate laws for the following reactions assuming each reaction follows an elementary rate laws.
C2H6 → C2H4 + H2
(CH3)3COOC(CH3)3 ⇌ C2H6 + 2CH3COCH3
(a)
(b)
C2H6 → C2H4 + H2
A → B C
(CH3)3COOC(CH3)3 ⇌ C2H6 + 2CH3COCH3
A ⇌ B C

5. Question (2) (a) (b) (c) (d) Write the rate law for the reaction:
if the reaction
is second order in B and overall third order
is zero order in A and first order in B
is zero order in both A and B
is first order in A and overall zero order
(a)
(b)
(c)
(d)

6. Question (3)(a) Let A = ONCB, B = NH3, C = Nitroaniline , D = NH4Cl
The formation of ortho-nitroaniline is formed from the reaction of ortho-nitrochlorobenzene (ONCB) and aqueous ammonia.
The liquid-phase reaction is first order in both ONCB and ammonia with k= m3/kmol-min at 188°C with E = 11,273 cal/mol. The initial entering concentration of ONCB and ammonia are 1.8 kmol/m3 and 6.6 kmol/m3 respectively.
Write the rate law for the rate of disappearance of ONCB in terms of concentration.
Let A = ONCB, B = NH3, C = Nitroaniline , D = NH4Cl

7. Question (3)(b) Species Entering Change Leaving A B C D A + 2B → C + D
Set up stoichiometric table for this reaction for a flow system
Species
Entering
Change
Leaving A B C D

8. Question (3)(c)
Explain how part (a) and (b) would be different for a batch system
For batch system,

9. Question (3)(d) Write –rA solely as a function of conversion.
For liquid phase rxn, υ = υ0

10. Question (3)(d)
Substituting the concentration of A & B;

11. Question (3)(e)
What is the initial rate of reaction (X=0) at 188°C and at 25°C
i) At T= 188°C, k =0.017m3/kmol-min
Substituting X=0 and k =0.017m3/kmol-min into (1);
---(1)

12. Question (3)(e)
What is the initial rate of reaction (X=0) at 188°C and at 25°C
ii) At T= 25°C ( K), k =? m3/kmol-min
Find k at T =25°C first
k at initial T is
k at any temperature is
Taking the ratio;
---(1)

13. Question (3)(e)
What is the initial rate of reaction (X=0) at 188°C and at 25°C
ii) Now we know that, at T= 25°C ( K), k = x 10-6 m3/kmol-min
Therefore, we can calculate –rA at 25° by susbtituting
k= x 10-6 m3/kmol-min, and X = 0 in eq (1).
---(1)

14. Question (3)(f) (i) At T= 188°C, k =0.0017m3/kmol-min
What is the rate of reaction when X = 0.9 at 188°C and at 25°C?
(i) At T= 188°C, k =0.0017m3/kmol-min
Substituting X=0.9 and k =0.017m3/kmol-min into (1);
---(1)

15. Question (3)(f)
What is the rate of reaction when X = 0.9 at 188°C and at 25°C?
(ii) From part (e) when T= 25°C, k = x 10-6 m3/kmol-min
Substituting X=0.9 and k = k = x 10-6 m3/kmol-min into (1);
---(1)

16. Question (3)(g)
What would be the corresponding CSTR volume at 25°C to achieve 90% conversion at 188°C for a feed rate of 2 dm3/min?
Substituting the value of CA0, υ0 and –rA(at 288°C & X=0.9);