Question

The equations showing the effect of temperature change on the heat of reaction is known as (a) Arrhenius equation (b) Kirchhoff's equation (c) Ostwald's equation (d) none of these

Short answer

The correct answer is (b) Kirchhoff's equation.

Step-by-step solution

Understand the Options

First, it's crucial to understand what each of the options represents. The Arrhenius equation illustrates the temperature dependence of reaction rates. The Kirchhoff's equation calculates heat capacity changes in chemical reactions, thus it connects the variation of the heat of reaction with the temperature. The Ostwald's equation is actually the Ostwald's dilution law, which concerns weak electrolytes.

Identify the Correct Answer

In this case, only Kirchhoff's equation describes the effect of temperature change on the heat of reaction, making Option (b) the correct answer.

Key concepts

Temperature Dependence

In the world of chemistry, understanding how temperature affects different variables is vital. One key aspect of this is how temperature impacts reaction rates and other properties, such as heat capacity. Kirchhoff's equation provides a crucial link in this aspect, as it explains how the heat of reaction changes with temperature. This is why it is known as the temperature dependence equation in the context of heat of reaction. By analyzing reactions at different temperatures, chemists can predict how much energy will be released or absorbed. This helps in designing processes that are efficient and safe.

• Keeps reactions predictable: Ensures reactions occur at the desired rate and efficiency.
• Enhances safety: Understanding temperature effects prevents unexpected or unsafe reactions.

Thus, temperature dependence in chemical reactions involves careful measurement and prediction of how temperature influences various reaction outcomes.

Heat of Reaction

The heat of reaction, also known as reaction enthalpy, is a core concept in thermodynamics. It describes the amount of heat energy either absorbed or released during a chemical reaction. Heating and cooling effects within a reaction are directly tied to whether the reaction is exothermic or endothermic. Kirchhoff's equation allows chemists to understand how this heat changes when temperature varies. This is because heat capacities of substances involved in the reaction might change with temperature. Understanding the heat of reaction is crucial for applications like:

• Determining energy requirements: Critical for industrial processes to ensure energy efficiency.
• Predicting reaction behavior: Helps in foreseeing the feasibility and spontaneity of reactions under different conditions.

Therefore, the heat of reaction is a fundamental aspect when it comes to understanding and utilizing chemical processes.

Chemical Reaction

A chemical reaction involves the rearrangement of atoms to transform substances. This process can involve both the breaking and forming of chemical bonds, which often results in energy changes. Kirchhoff's equation helps to understand how these energy changes, specifically the heat component, vary with temperature. Every chemical reaction can be described by an equation that represents:

• Reactants: Initial substances that undergo transformation.
• Products: New substances formed as a result of the reaction.

Knowledge about chemical reactions is key for: - Designing new materials and chemicals. - Devising energy-efficient methods in laboratories and industries. Thus, mastering chemical reactions allows chemists to predict and manipulate outcomes for various scientific applications.