Rate equations & orders of reaction

The rate constant, k, for a first order reaction is 6.19 × 10^–3 s^–1.

What is the half-life, in s, for the reaction?

A 4.29 × 10^–3

B 49

C 112

D 323

Nitrogen monoxide, NO, reacts with oxygen to form nitrogen dioxide, NO₂.

The rate of reaction increases in the presence of a heterogeneous platinum catalyst.

Explain why platinum is an example of a heterogeneous catalyst for Reaction 18.1.

Explain how the platinum catalyst increases the rate of reaction.

Include a labelled sketch of the Boltzmann distribution on the grid.

In industry, catalysts have great economic importance and benefits for increased sustainability.

Explain how the use of catalysts is beneficial to the environment.

The following data was obtained in a series of experiments on the rate of the reaction for Reaction 18.1 at a constant temperature.

Determine the orders with respect to NO and O₂. Explain your reasoning.

Determine the rate equation and calculate the rate constant, k, including units.

Complete the table by adding the missing value of ln k.

This question is about equilibrium and rates.

Using collision theory, explain why the gradient decreases over time.

* Use the graph to determine the order of reaction with respect to CV, the rate of the reaction at three minutes and the rate constant, k.

Your answer must show full working on the graph and on the lines below.

These questions are from different areas of chemistry.

This question is about two salts of rubidium (atomic number 37): RbClO₃ and RbClO₄.

The oxidation number of chlorine is different in the two rubidium salts, RbClO₃ and RbClO₄.

What is the name of RbClO₄?

A student carries out an experiment to determine the enthalpy change of solution of RbClO₃ using the method below.

• A 2.00 g sample of solid RbClO₃ is added to water in a well-insulated container. The initial temperature is 23.0 °C.

• The mixture is stirred until all the RbClO₃ has dissolved. The final temperature is 21.5 °C. The final solution has a mass of 102 g.

Determine the enthalpy change of solution, _solH, of RbClO₃ in kJ mol^–1.

Assume that the specific heat capacity of the solution is the same as that of pure water.

_solH (RbClO₃) =........ kJ mol^–1

A student investigates the rate of a reaction that is 1st order with respect to hydrochloric acid, HC l (aq).

• The student carries out a reaction using 0.680 mol dm^–3 HCl(aq). The initial rate is

• The student dilutes a different sample of 0.680 mol dm^–3 HCl(aq) with water. The pH of this diluted acid is 1.50.

• The student repeats the reaction using the same volume of this diluted acid.

Determine the initial rate using this diluted acid.

initial rate =........ mol dm^–3 s^–1

The half-life for a first order reaction is 80 s.

What is the rate constant k, in s^–1, for this reaction?

A 8.66 × 10^–3

B 0.0125

C 55.5

D 115

Your answer

A catalytic converter in a car removes nitrogen monoxide, NO, and carbon monoxide, CO, from the exhaust gases.

One reaction that happens in a catalytic converter is shown below.

Explain how increasing the temperature increases the rate of Reaction 16.1.

Include a labelled sketch, using Boltzmann distributions, on the grid below.

Label the axes.

Carbon monoxide also reacts with nitrogen dioxide as shown in Reaction 16.2.

The rate equation for Reaction 16.2 is shown below:

rate = k [NO₂(g)]²

Suggest a possible two-step mechanism for Reaction 16.2. The first step is much slower than the second step.

These short questions are from different areas of chemistry.

Explain why a CF₄ molecule has polar bonds but does not have an overall dipole.

Explain why a small proportion of molecules in water have a relative molecular mass of 20.

What is the partial pressure of O₂ (in Pa) in a gas mixture containing 21% O₂ by volume and with a total pressure of 1.0 × 10⁵ Pa?

What mass of carbon dioxide (in g) is formed by the complete combustion of 42.0 m³ (measured at RTP) of propane?

What is the number of oxygen atoms in 4.26 g of P₂O₅?

* Determine the rate constant and a possible two-step mechanism for this reaction that are

consistent with these results.

A student carries out an investigation to find the activation energy, E_a, and the pre-exponential factor, A, of a reaction.

The student determines the rate constant, k, at different temperatures, T. The student then plots a graph of ln k against 1 / T as shown below.

Draw a best-fit straight line and calculate the activation energy, in J mol^–1. Give your answer to three significant figures.

Show your working.

activation energy, E_a = +........ J mol^–1

Use the graph to calculate the value of the pre-exponential factor, A.

Show your working.