Askiitians Tutor Team
Last Activity: 13 Days ago
To understand why the heat required to boil water at 100°C (x) is equal to the heat required to evaporate water at 0°C (y), we need to delve into the concepts of phase changes and the specific heat capacities involved in these processes.
Phase Changes and Heat Transfer
Water can exist in three states: solid (ice), liquid (water), and gas (steam). The transitions between these states—melting, boiling, and evaporation—require energy, which is measured in joules. The key to your question lies in the definitions of boiling and evaporation.
Boiling vs. Evaporation
Boiling occurs when water reaches its boiling point (100°C at standard atmospheric pressure). At this temperature, water molecules have enough energy to break free from the liquid state and become steam. The heat required to accomplish this is known as the latent heat of vaporization.
On the other hand, evaporation can occur at any temperature, including 0°C. It happens when individual water molecules at the surface gain enough energy to escape into the air. The heat required for this process is also related to the latent heat of vaporization, albeit under different conditions.
Understanding the Heat Requirements
Now, let’s break down the heat requirements:
- For boiling (x): To convert 1g of water at 100°C to steam, you need to provide the latent heat of vaporization, which is approximately 2260 joules for 1g of water.
- For evaporation (y): To evaporate 1g of water at 0°C, you also need to provide the same latent heat of vaporization, which is again about 2260 joules.
Why x Equals y
Both processes require the same amount of energy because they involve the same fundamental transition from liquid to gas. The temperature at which the water starts (0°C for evaporation and 100°C for boiling) does not change the amount of energy needed to overcome the intermolecular forces holding the water molecules together in the liquid state.
In essence, while the initial conditions differ (temperature), the energy required to change the state from liquid to gas remains constant due to the nature of the phase change itself. This is why we find that x equals y.
Real-World Implications
This concept is crucial in various applications, from understanding weather patterns to designing efficient heating systems. For instance, knowing that the energy required for phase changes is consistent helps engineers calculate energy needs for heating or cooling systems effectively.
In summary, both boiling and evaporation require the same amount of energy to convert water from liquid to gas, which is why the heat required (x and y) is equal. Understanding these principles not only clarifies this specific question but also enhances your grasp of thermodynamics and energy transfer in general.