Introduction: just stuff dissolved in water and the
At the risk of sounding like im on drugs, aren’t liquids supper weird? Like, the idea that there is stuff without a shape, how did they get away without having a shape? And there aren’t that many of them like name three… My first choices were juice, milk and blood and I think it’s a little weird that I jumped from milk to blood but they are both produced by the body… I’ve gotten off topic. My point is that all those things are just stuff dissolved in water and the only pure non water liquid that the average human would run into would be liquid fats. Produced only by plants and animals. Liquidds are super weird and super rare of the hundred plus elements on the periodic table only two of them are liquid at room temperature. Lucky for us water is a really cool liquid so at least we have a quality over quantity scenario. Water is insane! If you put a drop of water on top of a flat surface of water it will bounce on top of it before affiliating itself with the water because of surface tension. Among the many amazing things water can do, I have always wondered why it bubbles (and more specifically boils), how do they boil. This research paper is an excuse for me to find out!
What causes liquids to boil? What is a “boiling point”?
The boiling point of a substance is the temperature at which it changes from a liquid state to a gas state throughout the bulk of the liquid at a given pressure. Boiling is the transition of a substance from the liquid to gaseous state of matter. When a liquid boils, its vapor pressure equals the atmospheric pressure. At high altitudes, liquids boil at a much lower temperature because there is less atmospheric pressure acting upon them.How do liquids boil?
A liquid can change to a gas at temperatures below the boiling point through a process called evaporation. Any change of state from a liquid to a gas at boiling point is considered vaporization. Evaporation is only a surface phenomenon, in which only the molecules located near the surface can evaporate. Boiling on the other hand deals with the totality of the liquid reaching the boiling point where molecules anywhere in the liquid system may be vaporized, resulting in the formation of vapor bubbles, hence what we observe as boiling.
What is saturation temperature?
Saturation temperature is another term that basically means boiling point and has to do with chemical thermodynamics. Saturation temperature is the temperature for a corresponding “Saturation Pressure” at which a liquid boils into the vapor phase. The liquid is said to be saturated with thermal energy. Any addition of energy results in a phase change. If the pressure in a system remains the same, a vapor at Saturation Temperature and Pressure will begin to condense into its liquid phase as heat is removed. Comparable, a liquid at Saturation Temperature and Pressure will boil into its vapor phase as additional thermal energy is applied. The boiling point is correlated with the temperature at which the vapor pressure of the substance equals the surrounding pressure. Therefore boiling point is dependent on the pressure.
What factors/forces affect the boiling point?
Molecules with stronger intermolecular force have higher boiling points. The molecules in a liquid are able to slide past each other. They are still however held close enough to each other by their intermolecular forces of attraction that they remain a liquid instead of a gas. If the temperature is high enough that it gives the molecules enough kinetic energy to break away from the rest of their system they can escape into the atmosphere as a gas. Liquids with weak intermolecular forces have weak attractions to each other and the molecules can escape into the gas phase with ease and therefore, their boiling points are lower. However, another factor is that of the molecules size. If the molecule is very large it will have more difficulty escaping the liquid and will require greater energy to do so. Therefore molecules that have a larger mass have higher boiling points. This puts water in a really interesting position. Water is very light compared to most elements so it should have a low boiling point but the truth is that it doesn’t because water is incredibly polar due to its double hydrogen bonding.
What happens when liquids boil?
Something that should be remembered is that boiling is usually represented by the appearance of bubbles containing vapor from the liquid. The bubbles that precede real boiling in the container are either water vapor forming next to a heat element or formerly dissolved air which will be condensed before it can get to the top of the liquid. The production of vapor requires energy and thus does not occur without some transfer of energy from another source. This source can be a hot surface or even another liquid including itself.
The dangers of boiling
Hot liquid will boil as it rises through the bulk liquid if the pressure of the environment drops to the vapor pressure of the liquid at its temperature. This production of vapor will quickly stop because the temperature of the liquid will be reduced by the vaporization thus reducing the vapor pressure. This production of vapor can produce catastrophic results. One refinery release (which resulted in an explosion that killed 15 people) was initiated by the movement of hot liquid from the bottom of an inadvertently filled tower. When the liquid rose the pressure dropped and the liquid began to boil. This further mixed the tower and produced more vapor which expanded greatly and forced liquid into the vapor line. The head of the liquid in a normally gas filled line caused the pressure relief valves to open and vented material into a “stand pipe” where it escaped and caused a vapor cloud. The vapor cloud ignited and the resulting explosion killed 15 people. (From the CSB report of the incident)