Chemical Kinetics
N_{2}O_{5} → 2NO_{2} + 1/2O_{2}
t/s | 0 | 300 | 600 |
[N_{2}O_{5}]/mol L^{–1} | 1.6 × 10^{–2} | 0.8 × 10^{–2} | 0.4 × 10^{–2} |
(a) Show that it follows first order reaction.
(b) Calculate the half-life.
(Given log 2 = 0.3010, log 4 = 0.6021)
For the first order thermal decomposition reaction, the following data were obtained:
C_{2}H_{5}Cl(g) → C_{2}H_{4}(g) + HCl(g)
Time/sec | Total pressure/ atm |
0 | 0.30 |
300 | 0.50 |
Calculate the rate constant.
(Given: log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021)
For the hydrolysis of methyl acetate in aqueous solution, the following results were obtained :
t/s | 0 | 30 | 60 |
[CH_{3}COOCH_{3}] / mol L^{–1} | 0.60 | 0.30 | 0.15 |
(i) Show that it follows pseudo first order reaction, as the concentration of water remains constant.
(ii) Calculate the average rate of reaction between the time interval 30 to 60 seconds.
(Given log 2 = 0.3010, log 4 = 0.6021)
Or
(a) For a reaction A + B → P, the rate is given by
Rate = k[A] [B]^{2}
(i) How is the rate of reaction affected if the concentration of B is doubled ?
(ii) What is the overall order of reaction if A is present in large excess ?
(b) A first order reaction takes 30 minutes for 50% completion. Calculate the time required for 90% completion of this reaction.
(log 2 = 0.3010)
For the hydrolysis of methyl acetate in aqueous solution, the following results were obtained :
t/s | 0 | 30 | 60 |
[CH_{3}COOCH_{3}] / mol L^{–1} | 0.60 | 0.30 | 0.15 |
(i) Show that it follows pseudo first order reaction, as the concentration of water remains constant.
(ii) Calculate the average rate of reaction between the time interval 30 to 60 seconds.
(Given log 2 = 0.3010, log 4 = 0.6021)
Or
(a) For a reaction A + B → P, the rate is given by
Rate = k[A] [B]^{2}
(i) How is the rate of reaction affected if the concentration of B is doubled ?
(ii) What is the overall order of reaction if A is present in large excess ?
(b) A first order reaction takes 30 minutes for 50% completion. Calculate the time required for 90% completion of this reaction.
(log 2 = 0.3010)
For the hydrolysis of methyl acetate in aqueous solution, the following results were obtained :
t/s | 0 | 30 | 60 |
[CH_{3}COOCH_{3}] / mol L^{–1} | 0.60 | 0.30 | 0.15 |
(i) Show that it follows pseudo first order reaction, as the concentration of water remains constant.
(ii) Calculate the average rate of reaction between the time interval 30 to 60 seconds.
(Given log 2 = 0.3010, log 4 = 0.6021)
Or
(a) For a reaction A + B → P, the rate is given by
Rate = k[A] [B]^{2}
(i) How is the rate of reaction affected if the concentration of B is doubled ?
(ii) What is the overall order of reaction if A is present in large excess ?
(b) A first order reaction takes 30 minutes for 50% completion. Calculate the time required for 90% completion of this reaction.
(log 2 = 0.3010)
SO_{2}Cl_{2} (g) → SO_{2} (g) + Cl_{2} (g)
Experiment | Time/s^{−1} | Total pressure/atm |
1 | 0 | 0·4 |
2 | 100 | 0·7 |
(Given: log 4 = 0·6021 and log 2 = 0·3010)
SO_{2}Cl_{2}(g) → SO_{2}(g) + Cl_{2}(g)
Experiment | Time/s^{−1} | Total pressure/atm |
1 2 |
0 100 |
0.4 0.7 |
(Given : log 4 = 0.6021, log 2 = 0.3010)
SO_{2}Cl_{2}(g) → SO_{2}(g) + Cl_{2}(g)
Experiment | Time/s^{−1} | Total pressure/atm |
1 2 |
0 100 |
0.4 0.7 |
(Given : log 4 = 0.6021, log 2 = 0.3010)
(i) Rate constant (k)
(ii) Half life period of a reaction (t_{1}_{/2})
The following data were obtained during the first order thermal decomposition of SO_{2}Cl_{2} at a constant volume :
SO_{2}Cl_{2} (g) → SO_{2} (g) + Cl_{2} (g)
Experiment |
Time/s^{−1} |
Total pressure/atm |
1 |
0 |
0·4 |
2 |
100 |
0·7 |
Calculate the rate constant.
(Given : log 4 = 0·6021, log 2 = 0·3010)
SO_{2}Cl_{2}(g) → SO_{2}(g) + Cl_{2}(g)
Experiment | Time/s^{−1} | Total pressure/atm |
1 2 |
0 100 |
0.4 0.7 |
(Given : log 4 = 0.6021, log 2 = 0.3010)
For the reaction
2NO_{(g)} + Cl_{2(g)} → 2 NOCl_{(g)}
The following data were collected. All the measurements were taken at 263 K:
Experiment No. |
Initial [NO] (M) |
Initial [Cl_{2}] (M) |
Initial rate of disappearance of Cl_{2} (M/min) |
1 |
0.15 |
0.15 |
0.60 |
2 |
0.15 |
0.30 |
1.20 |
3 |
0.30 |
0.15 |
2.40 |
4 |
0.25 |
0.25 |
? |
(a) Write the expression for rate law.
(b) Calculate the value of rate constant and specify its units.
(c) What is the initial rate of disappearance of Cl_{2 }in exp. 4?
For the reaction
2NO_{(g)} + Cl_{2(g)} → 2 NOCl_{(g)}
The following data were collected. All the measurements were taken at 263 K:
Experiment No. |
Initial [NO] (M) |
Initial [Cl_{2}] (M) |
Initial rate of disappearance of Cl_{2} (M/min) |
1 |
0.15 |
0.15 |
0.60 |
2 |
0.15 |
0.30 |
1.20 |
3 |
0.30 |
0.15 |
2.40 |
4 |
0.25 |
0.25 |
? |
(a) Write the expression for rate law.
(b) Calculate the value of rate constant and specify its units.
(c) What is the initial rate of disappearance of Cl_{2 }in exp. 4?
For the reaction
2NO_{(g)} + Cl_{2(g)} → 2 NOCl_{(g)}
The following data were collected. All the measurements were taken at 263 K:
Experiment No. |
Initial [NO] (M) |
Initial [Cl_{2}] (M) |
Initial rate of disappearance of Cl_{2} (M/min) |
1 |
0.15 |
0.15 |
0.60 |
2 |
0.15 |
0.30 |
1.20 |
3 |
0.30 |
0.15 |
2.40 |
4 |
0.25 |
0.25 |
? |
(a) Write the expression for rate law.
(b) Calculate the value of rate constant and specify its units.
(c) What is the initial rate of disappearance of Cl_{2 }in exp. 4?
Nitrogen pentoxide decomposes according to equation: 2N_{2}O_{5}(g) → 4NO_{2}(g) + O_{2}(g)
This first order reaction was allowed to proceed at 40° C and the data below were collected:
[N_{2}O_{5}] (M) | Time (min) |
0.400 | 0.00 |
0.289 | 20.0 |
0.209 | 40.0 |
0.151 | 60.0 |
0.109 | 80.0 |
(a) Calculate the rate constant. Include units with your answer.
(b) What will be the concentration of N_{2}O_{5} after 100 minutes?
(c) Calculate the initial rate of reaction.
Distinguish between reaction rate and reaction rate constant (specific reaction rate) of a reaction.