The half-life for radioactive decay of 14C is 5730 years. A wood sample contains only 80% of the 14C. The age of the wood sample would be-
1. 1898 years
2. 1765 years
3. 1931 years
4. 1860 years
The rate constant for the decomposition of hydrocarbons is 2.418 × 10–5 s–1 at 546 K. If the energy of activation is 179.9 kJ/mol,
the value of the pre-exponential factor will be:
1.
2.
3.
4.
For a reaction A → Product, with k = 2.0 × 10–2 s–1, if the initial concentration of A is 1.0 mol L–1, the concentration of A after 100 seconds would be :
1. | 0.23 mol L–1 | 2. | 0.18 mol L–1 |
3. | 0.11 mol L–1 | 4. | 0.13 mol L–1 |
The decomposition of sucrose follows the first-order rate law. For this decomposition, t1/2 is 3.00 hours. The fraction of a sample of sucrose that remains after 8 hours would be:
1. | 0.13 | 2. | 0.42 |
3. | 0.16 | 4. | 0.25 |
The decomposition of hydrocarbons follows the equation: k = (4.5 × 1011s–1) e–28000K/T
The activation energy (Ea) for the reaction would be:
1. 232.79 kJ mol–1
2. 245.86 kJ mol–1
3. 126.12 kJ mol–1
4. 242.51 kJ mol–1
The rate constant for the first-order decomposition of H2O2 is given by the equation:
\(log \ k \ = \ 14.34 \ - \ 1.25 \ \times \ 10^{4}\frac{K}{T}\).
The value of Ea for the reaction would be:
1. 249.34 kJ mol–1
2. 242.64 J mol–1
3. –275.68 kJ mol–1
4. 239.34 kJ mol–1
The decomposition of A into the product has a value of k as 4.5 × 103 s–1 at 10°C and energy of activation of 60 kJ mol–1. The temperature at which the rate constant becomes 1.5 × 104 s–1 would be -
1. \(24 \text { K} \)
2. \(24 ^\circ \text { C} \)
3. \(31 ^\circ \text { C} \)
4. \(38 ^\circ \text { C} \)
The rate of a reaction quadruples when the temperature changes from 293 K to 313 K. The energy of activation of the reaction would be -
1. 65.93 kJ mol–1
2. 52.85 kJ mol–1
3. 55.46 kJ mol–1
4. 60.93 kJ mol–1
The decomposition of NH3 on a platinum surface is a zero-order reaction. The rates of production of N2 and H2 will be respectively:
(given ; k = 2.5 × 10–4 mol–1 L s–1 )
1. | 2.5 × 10−4 mol L−1 s−1 and 5.5 × 10−4 mol L−1 s−1
|
2. | 2.5 × 10−4 mol L−1 s−1 and 7.5 × 10−4 mol L−1 s−1
|
3. | 1.5 × 10−4 mol L−1 s−1 and 4.5 × 10−4 mol L−1 s−1
|
4. | 0.5 × 10−4 mol L−1 s−1 and 3.5 × 10−4 mol L−1 s−1 |
The rate equation of a reaction is expressed as, Rate = \(k(P_{CH_{3}OCH_{3}})^{\frac{3}{2}}\)
(Unit of rate = bar min–1)
The units of the rate constant will be:
1. bar1/2 min
2. bar2 min–1
3. bar–1 min–2
4. bar–1/2 min–1