Question

Nitrogen gas reacts with oxygen gas to make \(\mathrm{NO}(\mathrm{g})\) while absorbing \(180 \mathrm{~kJ}\). Is this process exothermic or endothermic?

Short answer

The process is endothermic.

Step-by-step solution

Understanding Exothermic and Endothermic Reactions

An exothermic reaction releases energy, usually in the form of heat, to the surroundings. This means that the overall energy of the system decreases. In contrast, an endothermic reaction absorbs energy from the surroundings, resulting in an increase in the overall energy of the system.

Analyzing the Given Information

The reaction involves nitrogen gas reacting with oxygen gas to form NO(g). The problem states that this process absorbs \(180 \text{ kJ}\) of energy. This key detail indicates the nature of the reaction regarding energy changes in the system.

Applying the Concept

Since the process absorbs \(180 \text{ kJ}\) of energy, it is taking in energy from the surroundings. According to the definitions, when a reaction absorbs energy, it is considered endothermic.

Conclusion

Based on the information given and the analysis, this particular reaction is classified as endothermic because it absorbs \(180 \text{ kJ}\) of energy.

Key concepts

Chemical Reactions

Chemical reactions are processes where substances come together and transform into new ones. Every reaction involves changes at the molecular level, where atoms are rearranged to form new molecules. This can either release or absorb energy, depending on the nature of the reaction.

• Exothermic reactions release energy, typically as heat, meaning the products have less energy than the reactants.
• Endothermic reactions absorb energy, causing the products to have more energy than the reactants.

In the example given, the chemical reaction involves nitrogen ( {N}_{2}) and oxygen ( {O}_{2}) gases coming together to form nitric oxide ( {NO}), a process that absorbs energy. Understanding how substances interact at this fundamental level helps us figure out whether energy will be released or absorbed.

Energy Absorption

When a chemical reaction occurs, energy absorption may take place, especially in endothermic reactions. These reactions require an input of energy to proceed. This is because the bonds being broken absorb more energy than is released when new bonds form.
For the nitrogen and oxygen reaction, the absorption of 180 kJ indicates this specific energy input. This energy allows the reaction to progress, forming nitric oxide, while energy is taken from the surroundings. This is a key characteristic of endothermic reactions and reflects how energy plays a pivotal role in transforming reactants into products.

Thermodynamics

Thermodynamics is the study of energy transformations in chemical reactions. It gives us tools to understand how energy is transferred or transformed within a system. Such principles help categorize reactions as either endothermic or exothermic. Appling thermodynamic concepts, we see:

• In an endothermic reaction like the one with nitrogen and oxygen, energy is absorbed from the environment, increasing the internal energy.
• The process is guided by enthalpy changes, where a positive enthalpy change ( {H}) suggests that the reaction absorbs heat from the surroundings.

In this scenario, the absorption of 180 kJ indicates a positive enthalpy change, aligning with thermodynamic principles for classifying endothermic reactions.

Nitrogen and Oxygen Reaction

The reaction between nitrogen and oxygen gases is a classic example of an endothermic process. This chemical transformation involves combining {N}_{2} and {O}_{2} to form nitric oxide ( {NO}). During this process, 180 kJ of energy is absorbed.
Understanding this reaction involves grasping the concept that energy must be input to break strong nitrogen-nitrogen and oxygen-oxygen bonds. Only then can nitric oxide form, with its new chemical bonds. This kind of reaction is important in various industrial processes, showing how specific conditions (like energy input) can guide the production of desired products. By studying this reaction, we see how fundamental chemical principles apply to real-world applications.