When water changes to steam, the expansion ratio is?
The Correct Answer and Explanation is:
The expansion ratio of water when it changes to steam is approximately 1,600:1.
Explanation:
When water undergoes a phase change from liquid to gas (steam), it expands significantly. This expansion is due to the change in the molecular arrangement and the energy dynamics between the two phases.
- Physical Transition:
Water molecules in the liquid state are closely packed together, with intermolecular forces (hydrogen bonds) holding them in place. When heat is applied, these intermolecular forces are overcome, and the water molecules move farther apart as they transition into the gas phase, which is steam. - Volume Change:
The liquid phase of water has a much denser molecular structure compared to its gaseous phase. The density of liquid water is around 1,000 kg/m³ at room temperature, whereas the density of steam is much lower, approximately 0.6 kg/m³ at 100°C and 1 atmosphere of pressure. - The Expansion Ratio:
To calculate the expansion ratio, we compare the volume of water in its liquid state to its volume as steam. When 1 liter of liquid water is converted to steam, it expands to occupy about 1,600 liters. This vast increase in volume occurs because the gas phase has much more space between molecules than the liquid phase, leading to a dramatic increase in the volume. - Practical Implications:
This expansion is the reason why water vapor (steam) can cause significant pressure buildup in confined spaces (like in a pressure cooker or a steam engine). In everyday applications, the high expansion ratio of steam is utilized for driving engines or heating systems, where steam’s ability to do work is directly related to this expansive property.
In summary, the phase change from water to steam leads to an expansion ratio of about 1,600:1, driven by the significant difference in molecular density between liquid water and steam.