Final answer:
The reaction rate increases when the temperature increases as it results in more frequent and more energetic collisions between reactant particles. Other factors like pressure, concentration, and surface area also generally increase the reaction rate, and a catalyst does so by lowering the activation energy required.
Step-by-step explanation:
The effect of temperature on reaction rate is significant. As the temperature increases, the kinetic energy of the reactant particles also increases. This results in more frequent and more energetic collisions between the reacting particles, boosting the chances of successful collisions that lead to a reaction. Therefore, when the temperature increases, the reaction rate increases, corresponding to option (c).
In relation to other factors affecting the reaction rate:
- Pressure: For gaseous reactions, increasing the pressure results in particles being closer together, which also increases the reaction rate due to more frequent collisions.
- Concentration: Higher concentration of reactants leads to an increase in the number of collisions, and subsequently the reaction rate increases.
- Surface area: Increasing the surface area of reactants (e.g., by breaking a solid reactant into smaller pieces) exposes more particles for reactions, leading to an increased reaction rate.
A catalyst is a substance that increases the reaction rate without being consumed in the process. It works by providing an alternative reaction pathway with a lower activation energy, allowing more reactant particles to have sufficient energy to react upon collision.