# Chemical Kinetics

### For a first order reaction, the concentration of A changes

For a first order reaction, (A) → products, the concentration of A changes from 0.1 M to 0.025 M in 40 minutes. The rate of reaction when the concentration of A is 0.01 M is

1. 3.47 x 10-5 M/min
2. 1.73 x 10-4 M/min
3. 1.73 x 10-5 M/min
4. 3.47 x 10-4 M/min

### For the non-stoichiometric reaction 2A + B → C + D

For the non-stoichiometric reaction 2A + B → C + D, the following kinetic data were obtained in three separate experiments, all at 298 K.

The rate law for the formation of C is

1. dc/dt = k[A]2[B]
2. dc/dt = k[A]
3. dc/dt = k[A][B]
4. dc/dt = k[A][B]2

### A reaction involving two different reactants can never be

A reaction involving two different reactants can never be

1. unimolecular reaction
2. bimolecular reaction
3. second order reaction
4. first order reaction

### The rate of a chemical reaction doubles for every 10ºC rise of temperature

The rate of a chemical reaction doubles for every 10ºC rise of temperature. If the temperature is raised by 50ºC, the rate of the reaction increases by about

1. 10 times
2. 24 times
3. 32 times
4. 64 times

### The following mechanism has been proposed for the reaction of NO with Br2

The following mechanism has been proposed for the reaction of NO with Br2 to form NOBr.

NO(g) + Br2(g) ↔ NOBr2(g)

NOBr2(g) + NO(g) → 2NOBr(g)

If the second step is the rate determining step, the order of the reaction with respect to NO(g) is

1. 0
2. 1
3. 2
4. 3

### The half­-life of a radioisotope is four hours

The half­-life of a radioisotope is four hours. If the initial mass of the isotope was 200 g, the mass remaining after 24 hours undecayed is

1. 1.042 g
2. 2.084 g
3. 3.125 g
4. 4.167 g

### A reaction was found to be second order

A reaction was found to be second order with respect to the concentration of carbon monoxide. If the concentration of carbon monoxide is doubled, with everything else kept the same, the rate of reaction will be

1. remain unchanged
2. increased by a factor of 4
3. doubled
4. tripled

### The half ­life of a radioactive isotope is three hours

The half ­life of a radioactive isotope is three hours. If the initial mass of the isotope were 256 g, the mass of it remaining undecayed after 18 hours would be

1. 16.0 g
2. 12.0 g
3. 8.0 g
4. 4.0 g

### Decomposition of H2O2 follows a first order reaction. In fifty minutes the concentration

Decomposition of H2O2 follows a first order reaction. In fifty minutes the concentration of H2O2 decreases from 0.5 to 0.125 M in one such decomposition. When the concentration of H2O2 reaches 0.05 M, the rate of formation of O2 will be:

1. 6.93 × 10–4 mol min–1
2. 2.66 L min–1 at STP
3. 1.34 × 10–2 mol min–1
4. 6.93 × 10–2 mol min–1