Question

Effects of temperature on exothermic and endothermic reaction

Answer 1

Temperature has a significant impact on both exothermic and endothermic reactions, influencing their rates, equilibrium positions, and extent of reaction. Here’s how temperature affects each type of reaction:

### Exothermic Reactions

**Definition:** Exothermic reactions are those that release energy in the form of heat. Common examples include combustion and the formation of products from reactants (e.g., the reaction of hydrogen and oxygen to form water).

**Effects of Temperature:**
1. **Rate of Reaction:** Increasing the temperature generally increases the rate of exothermic reactions. Higher temperatures provide more kinetic energy to the reactant molecules, leading to more frequent and effective collisions.

2. **Equilibrium Position:** According to Le Chatelier's principle, if the temperature of an exothermic reaction is increased, the equilibrium will shift to favor the reactants to absorb the excess heat. Conversely, decreasing the temperature favors the formation of products.

3. **Energy Release:** At higher temperatures, the overall energy change for the reaction remains negative, but the amount of heat released may be slightly less when considering the equilibrium shift.

### Endothermic Reactions

**Definition:** Endothermic reactions absorb energy (usually in the form of heat) from their surroundings. Examples include photosynthesis and the dissolution of salts like ammonium nitrate in water.

**Effects of Temperature:**
1. **Rate of Reaction:** Like exothermic reactions, endothermic reactions typically become faster with an increase in temperature. Higher temperatures provide reactant molecules with more kinetic energy, allowing them to overcome activation energy barriers more easily.

2. **Equilibrium Position:** For endothermic reactions, increasing the temperature shifts the equilibrium position toward the products, as the system attempts to absorb the added heat. Conversely, lowering the temperature shifts the equilibrium toward the reactants.

3. **Energy Requirement:** In endothermic reactions, the overall energy change is positive, indicating that heat is absorbed. Increased temperature can further increase the extent to which the reaction proceeds toward products.

### Summary

1. **Exothermic Reactions:**
- Increasing temperature speeds up the reaction rate.
- Higher temperatures favor reactants at equilibrium.

2. **Endothermic Reactions:**
- Increasing temperature speeds up the reaction rate.
- Higher temperatures favor products at equilibrium.

In both types of reactions, temperature plays a crucial role in not only determining the speed of the reaction but also influencing the position of equilibrium, thereby affecting the overall yield of the products.