does oil evaporate
Oil evaporates very slowly. Oil doesn’t mix with water, and most oils are less dense than water. So oil floats on top of water, and usually makes a very thin layer, covering all the water you have, or else it spreads out until the oil layer is just one or two molecules thick and you run out of oil.
Most vegetable cooking oils are classified as fixed oils. However, if you set out a container of most cooking oils, it would partially evaporate very slowly over months to years leaving a sticky varnish. You can see this varnish on the sides of pots and baking pans where the …
Jun 29, 2007 · Answers. Oils can evaporate, but they have a much lower vapor pressure at room temperature than does water. I have experienced the evaporation of oil when I heat it up for use as a high-temperature oil bath for heating chemical reactions. After a few hours at temperatures around 180C, you can see the oil level has gone down a bit.
Q & A: Oil and evaporation of water. Some oils evaporate themselves, though, and if you wait long enough, the oil may evaporate away, leaving a hole for the water underneath to evaporate. If the oil layer is too thin, it may leave a hole somewhere for the water molecules to escape by evaporation.
Jul 20, 2013 · Yes, oil can evaporate. Any oil is a mixture of a bunch of different substances which evaporate at different temperatures– In general, the oils with smaller molecules will evaporate more easily than those with larger molecules. This process is used in oil refineries to separate out the different components, which are used for different purposes.
As oil breaks up before it boils, there is no oil evaporation. You can destroy oil by heating it, because it will turn into something different than oil. You can also burn it by heating it in the presence of oxygen, and this is what happens when you see smoke coming from your pan.
I am afraid Chef Flambe’s answer is wrong. Not everything has a melting point and a boiling point. Oil is made of big organic molecules, containing long carbon chains*. Unlike anorganic substances with small molecules (like water), heating oil does not lead to a point where the molecules stop attracting each other (that would be the boiling point). Instead, the big, fragile molecules just break up. Which means that oil has no boiling point at all, and it is impossible to produce oil in a gas phase. (You can produce something similar to “oil vapor” with a mister, but this consists of tiny droplets of liquid oil, not a real gas). As oil breaks up before it boils, there is no oil evaporation. You can destroy oil by heating it, because it will turn into something different than oil. You can also burn it by heating it in the presence of oxygen, and this is what happens when you see smoke coming from your pan. (This is chemically different from simple breaking up of molecules). But no, it does not evaporate. The chambers of the chimney get a greasy film because: 1) the particles in the smoke from smoking oil can feel somewhat greasy (pure soot feels greasy too) 2) when your oil breaks down under heat, some of the new molecules (pieces of oil molecules) can be light enough to become air borne and go up and build a film. While technically not an edible oil any more, they can have a greasy feeling to them. 3) When you fry, oil droplets fly through the air. You notice it on the stove around your pan, but I bet some droplets are small enough to be carried by the upward draft of hot air into the chimney. *I simplified here a bit, because the oils we cook with are not made from a single chemical compound, they are a mix of different compounds. But the explanation still works for the mix, because it is always the same type of compound.16Yes, every substance theoretically has a boiling point, depending on pressure too (hydrogen at 0K in atmospheric pressure is still a gas). Still, quite a few substances are flammable – with flash point far below their boiling point. Oil, for example, will first start smoking, then go up in flames long before reaching its boiling point in our atmosphere with ~20% oxygen. Moreover, some substances undergo significant chemical reactions at certain temperatures, meaning whatever would eventually reach the boiling point will no longer be the original substance (thus the theoretical boiling point – the substance can’t reach it because it will cease to exist and become something entirely different before reaching it.) I’m not entirely sure, but I’m fairly convinced thermal cracking temperature of oil is still below its boiling point, meaning no, even if you remove oxygen, oil will first separate into simple hydrocarbons, before they begin boiling. OTOH, vegetable oil dries up – gets thick and sticky (although very slowly), meaning it shouldn’t be used for bearings, hinges and the like. But that’s not really on-topic.2Everything has a melting point and a vapour point but oil needs the extra heat added to get it to the vapour point.
The smoke you see is the oil breaking down and turning into vapour. However, when you get oil build up in the oven hoods what is usually happening is a combination of vapourized oils and regular oil droplets which have been carried up with help from steam.0While mixtures do have a specific boiling point, the amount of each component that boils off is not the same. If one of the components has a low boiling point compared to the others, then it is said to be more volatile, and so more of this component will boil off than the others when the boiling point is reached. Also, when you get above this volatile component’s boiling point, it will be evaporating a fair amount even if the entire mixture isn’t boiling. However, in the case of a mixture that interacts a lot on a molecular level, the situation is different. Water and alcohol are both very polar, and hold to each other relatively strongly. When this happens, once you boil off a certain amount of alcohol, you won’t decrease the concentration, because the small amount left is held as tightly as the water is. However, in the case of oil, because air is present, the high temperature causes the oil to break down to the same components as you would get if you burnt it, even though it isn’t technically burning (i.e. with a flame). When it burns, ideally, carbon dioxide and water is formed. However, since the temperature isn’t as high as in a furnace for example, there is a lot of residual carbon left over. The airflow from the hot surface of the frying pan etc. pushes the carbon (Smoke), which is still very hot, onto the steel or brick, where it binds to imperfections in the steel’s surface. Likewise, low boiling point oils can pass to the surfaces above, and very small droplets of more high boiling point oils can be carried upward in the bulk flow of hot air rising from the pan also. All this is from a chemical engineering perspective, but I hope you can read between the lines.0
Lighter oils will usually be thinner than the high molecular weight oils. Basically if you can smell a pure oil, then you are basically detecting the molecules that have evaporated. Sometimes you smell additives or other impurities that are of low molecular weight.
This would seemingly make oil evaporate more quickly than water, however, these weak forces increase in strength with increasing number of electrons in the molecule. Oil has a much greater mass than water, and thus has many more electrons than water does. I am sure others will elaborate.
Top responsesAll other things being equal, smaller molecules are more readily vaporized than larger ones. The water molecule (H2O) approximately 50x smaller … read more3 votesFor one thing, although oil is non-polar and only exhibits relatively weak inter-molecular forces (forces that act to bind neighboring molecules together … read more2 votesAll though there is a very elaborate explanation through inter-molecular forces (van der waals, hydrogen bonding etc) for the same reason but easier to … read more1 voteSee all
City driving tends to be more becaues it spends By the way, it does not evaporate. It gets burned. There’s always a miniscule amount that remains on the cylinder walls after the oil rings pass by and provides some lubrication for the compression rings, and that gets burned in …
Synthetic oil does not react to temperature changes as petroleum based motor oil. Synthetic motor oil will not thicken during cold temperatures which will make engine starting and oil pressure buildup better. Synthetic motor oil does not evaporate as quickly. This reduces the risk of oil sludge and replacing oil …
Even solids evaporate. For example, camphor evaporates. This fact can be verified simply by their smell and the reduction of its volume over time. And in fact, many substances, in any physical state (phase) may evaporate. And this is measured by i
Oct 07, 2002 · Oil will evaporate at temps much lower than 250C, but you’d have to run the ASTM test for a much longer period of time. This test does corrolate very well with oil consumption in actual use. Accelerated aging tests are commonly used to look at degradation of polymeric materials.