The thermochemical equation for the reaction of carbon dioxide with sulfur dioxide is shown below. How can the reaction be described : co2 (g) + 2s0s (g) + 1104 kj - > cs2 (g) + 302 (g)

a. it is exothermic

b. has low activation energy

c. it is endothermic

d. has high activation energy

Answer: d. has high activation energy

Activation energy is the energy that a system requires to start a certain process. Also, it is the minimum energy necessary for a given chemical reaction to occur. For a reaction to occur between two molecules, they must collide in the correct orientation and have a minimum amount of energy equal to the activation energy.

As the molecules approach, their electron clouds repel, so energy is required for the collision to occur and therefore the reaction. The activation energy comes from the heat of the system, that is, the translational, vibrational energy, etc. of each molecule. However, if this energy is not enough, the reaction will not be spontaneous.

A reaction between two molecules can be favored by supplying energy to the system. In the case raised in the question, energy equal to 1104 kJ is provided to the system to favor the next reaction

CO2 (g) + 2SO2 (g) → CS2 (g) + 3O2 (g)

Since the energy equal to 1104 kJ is included in the reactants, it can be deduced that it is the energy that is provided to the system for the reaction to occur. However, from the value of this energy it can not be said whether the system is endothermic or exothermic since it is a kinetic variable and the variables of this type do not allow predicting the thermodynamic behavior of a system.

Furthermore, it can be seen that the value of this energy is considerably high, therefore the reaction described has a high activation energy.