Question

Chemical reactions occur when molecules or atoms collide in a way that the bonds between atoms break and new bonds form. Breaking the bonds of the reactants requires energy, whereas bond formation releases energy. Select the true statements regarding energy changes during a reaction. Increasing the concentration of reactants increases the number of collisions, and the reaction goes faster. If the heat of reaction, Δ𝻠, is positive, the energy of the products is lower than the energy of the reactants and the reaction is endothermic. When the activation energy is low, the reaction rate is slow. The activation energy, đť¸a , of the forward reaction is the difference between the energy of the products and the energy of the transition state. Decreasing the temperature decreases the kinetic energy of the reactants, and the reaction goes more slowly. Reactants must collide with proper orientation and with energy greater than or equal to the activation energy for a reaction to occur. The energy of a collision between atoms or molecules must be greater than or equal to the activation energy, đť¸a , for bonds to be broken.

Answer 1

The correct statements are as follows:  

1. Reactants must collide, with proper orientations, with the energy greater than or equal to the activation energy for a reaction to take place. It is a correct statement, as to undergo a chemical reaction, the atoms should exhibit proper orientations and enough energy to reach the activation energy.

2. Increasing the concentration of a reactant increases the number of collisions, and the reaction goes faster. The mentioned statement is true, as when increasing the concentration of reactants, there should be more reactants. Thus, the collision will be more that makes the reaction to go faster.  

3. The energy of a collision between the molecules or atoms must be greater than the activation energy to break the bonds. The given statement is true, as, with the increase in activation energy, the reaction will get slower. Thus, the energy of the reactants is greater in comparison to the activation energy, and then the reaction is faster to break the bond.  

4. Decreasing the temperature decreases the kinetic energy of the reactants, and the reaction goes very slowly. The given statement is true, as when the temperature decreases, the kinetic energy that is required to dissociate the bond, also decreases. This undergoes a slow reaction.