What is meant by the term lower in energy? Which is lower in energy, a mixture of hydrogen and oxygen gases or liquid water? How do you know? Which of the two is more stable? How do you know?

The term "lower in energy" refers to a system or substance with less potential energy compared to another system or substance. Lowering the energy of a system leads to increased stability. In chemistry, when a chemical reaction occurs, the molecules with lower energy are typically the more stable products and require less energy to maintain their structure.

In order to compare the energy levels between a mixture of hydrogen and oxygen gases and liquid water, we need to study their chemical compositions and the energy changes associated with the formation of chemical bonds. A mixture of hydrogen and oxygen gases consists of separate H2 and O2 molecules. In this gaseous state, the molecules are moving freely and have a higher potential energy. On the other hand, liquid water consists of H2O molecules, formed when hydrogen and oxygen gases chemically react with each other. During the formation of the water molecule, two hydrogen atoms combine with one oxygen atom, releasing energy in the process.

The chemical reaction between hydrogen and oxygen gases can be represented as: \[2H_{2(g)} + O_{2(g)} \rightarrow 2H_{2O(l)}\] This reaction is exothermic, meaning it releases energy in the form of heat and light. The energy released during the formation of water molecules is mainly due to the bond formation between hydrogen and oxygen atoms, creating strong and stable chemical bonds. The energy released during this reaction lowers the potential energy of the system as a whole.

Since the formation of water molecules from hydrogen and oxygen gases is an exothermic process, the potential energy of the system decreases as a result. Liquid water has a lower potential energy than the mixture of hydrogen and oxygen gases, and thus it is considered to be "lower in energy". A substance with lower potential energy is typically more stable, as it requires less energy to maintain its structure. Therefore, liquid water is more stable than the mixture of hydrogen and oxygen gases. In conclusion, the term "lower in energy" refers to substances with less potential energy and increased stability. Liquid water has a lower potential energy and is more stable than a mixture of hydrogen and oxygen gases due to the strong chemical bonds formed between hydrogen and oxygen atoms during the exothermic reaction.