A flask partially full of liquid water is heated to boiling and capped cold water is poured over the flask. The water boils even more vigorously explain
The boiling point of a solvent is the temperature at which the vapor pressure of the solvent equals atmospheric pressure (the pressure surrounding the solvent in the case of a capped flask). So, a boiling solution means the vapor pressure = 760 mm Hg if the atmospheric pressure is 760 mm. Now, we cap the flask, run cold water over the outside. What happens. The cold water reduces the temperature of the boiling water. (P1/T1) = (P2/T2) which means that the pressure inside the flask is reduced significantly, the vapor pressure is reduced also; however, the vapor pressure of the liquid STILL IS as high or higher than the pressure above it and that is the definition of boiling. The solution continues to boil. This is the same phenomenon that exists when boiling water on top of Pike's Peak. The atmospheric pressure is lower than at the base of the mountain and water boils at a lower temperature; i.e., when the vapor pressure of the water is less than 760 mm.
The phenomenon of the water boiling more vigorously when cold water is poured over a partially full flask that is already heated to boiling is due to a process called "superheating" or "nucleate boiling."
When the flask is heated, the liquid water inside starts to absorb heat energy, causing the temperature to rise. Eventually, the water reaches its boiling point, which is when the liquid turns into vapor or steam. At this point, the water molecules at the surface of the liquid gain enough energy to overcome the atmospheric pressure and escape into the air as steam bubbles.
Now, when cold water is poured over the flask, it rapidly lowers the temperature of the flask and its contents. This sudden decrease in temperature causes a drastic change in pressure inside the flask. Due to the lower temperature and increased pressure, the water inside the flask becomes superheated.
Superheating occurs when a liquid is heated above its boiling point, but still remains in the liquid state due to the absence of nucleation sites. In other words, the water boils at a higher temperature than its boiling point without actually turning into steam.
However, when cold water is poured over the flask, the temperature drops, and tiny air bubbles or impurities in the water provide nucleation sites for the superheated water. These nucleation sites allow the superheated water to rapidly convert into steam, resulting in a more vigorous boiling process compared to before.
In summary, pouring cold water over a heated flask partially filled with liquid water causes the superheated water inside to rapidly boil once it encounters nucleation sites created by the cold water. This leads to a more vigorous boiling process.
When a flask partially filled with liquid water is heated, the heat increases the temperature of the water molecules. As the temperature rises, the molecules gain kinetic energy, which causes them to move faster and collide with each other more frequently.
When the water reaches its boiling point, which is typically 100 degrees Celsius or 212 degrees Fahrenheit at standard atmospheric pressure, the water molecules have enough energy to overcome the intermolecular forces holding them together in the liquid state. This results in the formation of water vapor or steam.
As the flask is capped and cold water is poured over it, the surrounding cold water reduces the temperature of the flask and the areas in contact with it. This creates a temperature gradient, with the cooler areas being in contact with the cold water and the hotter areas containing the heated water.
The difference in temperature between the heated water and the colder flask causes convection currents in the water. These currents are created by the density difference between the hot and cold regions of the water. The heated water near the bottom of the flask becomes less dense due to the increase in temperature, while the cold water poured over the flask remains denser.
The movement of liquid water due to convection currents enhances the contact between the water and the hot surfaces of the flask. This leads to more rapid transfer of heat from the flask to the water, accelerating the boiling process.
Overall, the combination of heating the flask and pouring cold water over it creates a temperature difference that drives convection currents in the liquid water, resulting in more vigorous boiling.