IB Chemistry HL 4.1 Reactivity Question Bank

The increased concentration of carbon dioxide in the atmosphere is thought to result from the increased combustion of fossil fuels such as petroleum.

Outline why the energy available from an engine will be less than these theoretical values.

Two groups of students (Group A and Group B) carried out a project* on the chemistry of some group 7 elements (the halogens) and their compounds.

In the first part of the project, the two groups had a sample of iodine monochloride (a corrosive brown liquid) prepared for them by their teacher using the following reaction.

The following data were recorded.

Using a digital thermometer, the students discovered that the reaction was exothermic. State the sign of the enthalpy change of the reaction, $\Delta H$.

Phenylethene (styrene) is produced from ethylbenzene in a gas-phase equilibrium.

The forward reaction is endothermic, uses iron(III) oxide as a catalyst, and takes place at 900 K .

Sketch the energy profile for the reaction, both with and without the catalyst, labelling $\Delta H$ and the activation energies.