Water molecules and hydrogen atoms are different entities with distinct properties. Here are the key differences:
Composition: A water molecule (H2O) consists of two hydrogen atoms (H) bonded to one oxygen atom (O). It forms a stable compound with unique properties due to the nature of its chemical bonding. Hydrogen atoms, on the other hand, exist as single, unbound atoms.
Physical state: Water is a liquid at standard temperature and pressure, whereas hydrogen gas (H2) is a colorless, odorless, and highly flammable gas.
Energy content: Water does not readily release energy when broken down into its constituent elements. Hydrogen gas, however, is highly energy-dense and combustible, making it a potential fuel source.
Regarding your question about using water in car engines instead of pure hydrogen gas, here are a few reasons:
Energy storage: Water does not store energy as effectively as hydrogen gas. In order to use water as a fuel, it would need to be electrolyzed (split into hydrogen and oxygen) first, which requires energy input. The resulting hydrogen gas can then be used as a fuel source. Using water directly as a fuel in car engines would require a substantial amount of energy to convert it into hydrogen gas, making the overall process inefficient.
Safety and storage: Hydrogen gas can be stored and transported more easily than water, as it has a lower density and is less corrosive. Water, in its liquid form, would require significantly larger storage tanks and pose challenges in terms of transportation and infrastructure.
Infrastructure and technology: The existing infrastructure for car engines, such as internal combustion engines or fuel cells, is designed to use hydrogen gas as a fuel. Switching to water as a fuel would require substantial modifications to the engine design and infrastructure, which would be cost-prohibitive.
Environmental impact: Using hydrogen gas produced from renewable sources (such as electrolysis using renewable electricity) can potentially provide a cleaner energy option compared to fossil fuels. Water as a direct fuel source would not have the same environmental benefits unless the process of generating hydrogen gas from water is performed using renewable energy sources.
While water is not used directly as a fuel in car engines, it can still be utilized indirectly through processes like electrolysis to produce hydrogen gas, which can then be used as a clean fuel source in fuel cell vehicles or hydrogen combustion engines.