Boiling Point of Water at 762 mmHg

The boiling point of water is a fundamental concept in chemistry and physics, often defined as the temperature at which a liquid turns into vapor under standard atmospheric pressure (760 mmHg). At standard atmospheric pressure, water boils at 100 degrees Celsius (212°F).

The Impact of Atmospheric Pressure on Boiling Point

However, the boiling point of water changes with variations in atmospheric pressure. This relationship is due to the fundamental principle that the boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals the surrounding atmospheric pressure. Thus, when the pressure is increased, the boiling point of water also increases.

Calculating the Boiling Point at 762 mmHg

When the pressure is slightly higher than the standard atmospheric pressure, for example at 762 mmHg, the boiling point of water will be slightly above its standard value of 100°C. The exact boiling point can be determined more accurately using steam tables or the Clausius-Clapeyron equation.

A rough estimate can be made as follows:

Increment in pressure  762 mmHg - 760 mmHg  2 mmHgEstimated increase in boiling point  (2 mmHg / 10 mmHg) * 0.3°C ≈ 0.06°CEstimated boiling point ≈ 100°C   0.06°C ≈ 100.06°C

Therefore, the boiling point of water at 762 mmHg is approximately 100.06°C.

Understanding the Definition of Boiling Point

The standard definition of the boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals the surrounding ambient pressure. In simpler terms, it is the point at which bubbles of vapor form directly in the liquid and rise to the surface.

Boiling occurs because the vapor pressure of the liquid equals the pressure exerted on the liquid by its surroundings. Since 762 mmHg is just slightly above standard atmospheric pressure, the increase in the ambient pressure means that the liquid requires a slightly higher temperature to achieve the same vapor pressure.

aLTERNAte Methods for Determining Boiling Point

While a rough estimate can be made using simple equations, more precise methods involve steam tables and the Clausius-Clapeyron equation. Steam tables are a set of tables that provide the state (temperature and pressure) at which water vaporizes under different conditions. The Clausius-Clapeyron equation, on the other hand, provides a relationship between the vapor pressure of a substance and its temperature, based on certain assumptions and measurements.

Real-world Implications

This variation in boiling point with pressure has practical implications in various fields such as chemistry, food preparation, and industrial processes. For example, in high-altitude areas where the atmospheric pressure is lower, water boils at a lower temperature (less than 100°C). Conversely, in high-pressure systems, the boiling point of water is higher. Understanding this relationship helps in regulating cooking times and equipment design.

In conclusion, the boiling point of water at 762 mmHg is approximately 100.06°C. This slight increase reflects the relationship between vapor pressure and boiling point, which is a crucial principle in understanding the behavior of liquids under various conditions.