1988-7-b-iv-cre

Liquid \(A\) decomposes by first order kinetics in an isothermal batch reactor. Fifty percent of \(A\) is converted in 300 seconds. The time required for a conversion of 75 percent is

- \(300 \times 0.75/0.25\) seconds
- \(300 \ln 1\) seconds
- \(300 \ln (0.5/0.25)\) seconds
- \(300 [\ln (0.25) / \ln (0.5)]\) seconds

1989-7-i-b-cre

For the following reaction, the rate constant at 373 K is 0.5 per minute. \[ 0.5A + B \rightarrow C \] The overall order of the reaction is

- 0.5
- 1.0
- 1.5
- 0

1992-2-c-cre

A gaseous reaction \(A\rightarrow 2B+C\) takes place isothermally in a constant pressure reactor. Starting with a gaseous mixture containing 50% \(A\) (rest inerts), the ratio of final to initial volume is found to be 1.6. The percentage conversion of
\(A\) is

- 30
- 50
- 60
- 74

1992-8-a-cre

The conversion of a reactant, undergoing a first order reaction, at a time equal to three times the half life of the reaction is

- 0.875
- 0.5
- 0.425
- not possible to calculate because of insufficient data

1999-2-14-cre

Consider the n\(^{th}\) order irreversible liquid phase reaction \(A \rightarrow B\). Which one of the following plots involving half-life of the reaction \((t_{1/2})\) and the initial reactant concentration \((C_{A0})\) gives a straight line plot?

- \(C_{A0}\) vs. \(t_{1/2}\)
- \(\ln C_{A0}\) vs. \(t_{1/2}\)
- \(C_{A0}\) vs. \(\ln t_{1/2}\)
- \(\ln C_{A0}\) vs. \(\ln t_{1/2}\)

2000-1-19-cre

The reaction \(A\rightarrow B\) is conducted in an isothermal batch reactor. If the conversion of \(A\) increases linearly with holding time, then the order of the reaction is

- 0
- 1
- 1.5
- 2

2000-2-17-cre

The following half-life data are available for the irreversible liquid phase reaction, \[ A \rightarrow \text { Products} \]

Initial concentration (kmol/m ^{3}) |
Half-life (min) |

2 | 2 |

8 | 1 |

The overall order of the reaction is

- 0.5
- 1
- 1.5
- 2

2001-1-14-cre

The conversion for a second order, irreversible reaction (constant volume), \(A \stackrel {k_2}{\longrightarrow } B\), in batch mode is given by

- \(\displaystyle \frac {1}{1+k_2C_{A0}t}\)
- \(\displaystyle \frac {k_2C_{A0}t}{1+k_2C_{A0}t}\)
- \(\displaystyle \frac {(k_2C_{A0}t)^2}{1+k_2C_{A0}t}\)
- \(\displaystyle \frac {k_2C_{A0}t}{(1+k_2C_{A0}t)^2}\)

2001-2-17-cre

The first-order, gas phase reaction \(A \stackrel {k_1}{\rightarrow } 2B\) is conducted isothermally in batch mode. The rate of change of conversion with time is given by

- \(\displaystyle dX_A/dt = k_1(1-X_A)^2(1+2X_A)\)
- \(\displaystyle dX_A/dt = k_1(1-X_A)(1+0.5X_A)\)
- \(\displaystyle dX_A/dt = k_1(1-X_A)\)
- \(\displaystyle dX_A/dt = k_1(1-X_A)/(1+X_A)\)

2004-73-cre

For an isothermal second order aqueous phase reaction \(A \rightarrow B\), the ratio of the time required for 90% conversion to the time required for 45% conversion is

- 2
- 4
- 11
- 22

2005-26-cre

For the liquid phase reaction \(A \rightarrow P\), in a series of experiments in a batch reactor, the half-life \(t_{1/2}\) was found to be inversely proportional to the square root of the initial concentration of \(A\). The order of the reaction is

- \(3/2\)
- \(1\)
- \(+1/2\)
- \(-1/2\)

2006-16-cre

A first order reversible reaction \(A\xrightleftharpoons [k_2]{k_1} B\) occurs in a batch reactor. The exponential decay of the concentration of \(A\) has the time constant

- \(\dfrac {1}{k_1}\)
- \(\dfrac {1}{k_2}\)
- \(\dfrac {1}{k_1-k_2}\)
- \(\dfrac {1}{k_1+k_2}\)

2009-14-cre

The half-life of a first order liquid phase reaction is 30 seconds. Then the rate constant, in min^{-1}, is

- 0.0231
- 0.602
- 1.386
- 2.0

2012-19-cre

The half-life of an \(n^{\text {th}}\) order reaction in a batch reactor depends on

- only the rate constant
- only the rate constant and the order of the reaction
- only the rate constant and the initial reactant concentration
- the rate constant, initial reactant concentration, and the order of the reaction

2015-18-cre

For which reaction order, the half-life of the reactant is half of the full lifetime (time for 100% conversion) of the reactant?

- Zero order
- Half order
- First order
- Second order

2015-19-cre

An irreversible, homogeneous reaction \(A\rightarrow \text {products}\), has the rate expression: \[ \text {Rate} = \frac {2C_A^2+0.1C_A}{1+50C_A}, \qquad \text {where \(C_A\) is the concentration of \(A\).} \] \(C_A\) varies in the range 0.5 - 50 mol/m^{3}.

For very high concentrations of \(A\), the reaction order tends to:

- 0
- 1
- 1.5
- 2

2007-58-cre

The following rate-concentration data are calculated from experiment. Find the activation energy temperature (\(E/R\)) of the first order reaction.

\(d_p\) | \(C_A\) | \(-r_A\) | \(T\) |
---|---|---|---|

1 | 20 | 1 | 480 |

2 | 40 | 2 | 480 |

2 | 40 | 3 | 500 |

- 2432.8
- 4865.6
- 9731.2
- 13183.3

2014-37-cre

A homogeneous reaction (\(R\rightarrow P\)) occurs in a batch reactor. The conversion of the reactant \(R\) is 67% after 10 minutes and 80% after 20 minutes. The rate equation for this reaction is

- \(-r_R=k\)
- \(-r_R=kC_R^2\)
- \(-r_R=kC_R^3\)
- \(-r_R=kC_R^{0.5}\)

The concentration versus batch time data for a constant volume, isothermal batch reactor is given in the table below.

\(t\) (s) | 0 | 30 | 60 | 90 | 120 | 150 | 180 |
---|---|---|---|---|---|---|---|

\(C_A\) (kmol/m\(^3\)) | 1.00 | 0.92 | 0.89 | 0.81 | 0.76 | 0.72 | 0.70 |

Assuming the reaction to be first order in \(A\), the best value of \(k\) by least squares regression is found to be = _______________ \(\times 10^{-3}\) s\(^{-1}\)

BT-2016-48-cre

Decimal reduction of bacterial spores is 23 min at 121^{o}C and the death kinetics follow first order. One litre medium containing \(10^5\) spores per mL was sterilized for 10 min at 121^{o}C in a batch sterilizer. The number of spores
in the medium after sterilization (assuming destruction of spores in heating and cooling period is negligible) will be ____________\(\times 10^7\).

BT-2018-48-cre

Mammalian cells in active growth phase were seeded at a density of \(1\times 10^5\) cells/mL. After 72 hours, \(1\times 10^6\) cells/mL were obtained. The population double time of the cells in hours is (up to two decimal places) ____________

0700-3-cre

Consider the reaction \(A+2B\rightarrow R\). This reaction was carried out and the following initial-rate data were reported. Determine the overall order of reaction and the reaction rate constant.

Run No. | \(C_{A0}\) (mol/litre) | \(C_{B0}\) (mol/litre) | Initial rate (mol/litre.s) |
---|---|---|---|

1 | 0.10 | 0.10 | 1.01 |

2 | 0.15 | 0.10 | 1.51 |

3 | 0.10 | 0.20 | 2.01 |

Last Modified on: 01-May-2024

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