What Happens to Alcohol When it Evaporates?

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In summary: Generally speaking, most cleaning agents will not cause any health concerns if they are used in moderation. I see no reason to worry. If it is giving you headaches, ventilate the room (or look for another roommate). Generally speaking, most cleaning agents will not cause any health concerns if they are used in moderation.
  • #1
bballwaterboy
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So, let's say you have either a bottle of rubbing alcohol (isopropyl) or a bottle of drinking alcohol (ethanol) and you leave it in the open air for a day or two (or however long it takes for it to evaporate). What happens when the alcohol evaporates into the air? Supposedly, the alcohol from the liquid goes away and you're left with water right? That's why you have to put lid tightly on alcohol.

My question is where does the alcohol go? Does it chemically break down or something and just no longer exist? Or is it still existing in some gaseous/vaporous state in the air? Like is the alcohol still lingering in the air around you (like in the form of fumes or something)?

Oh and lastly, why does the alcohol part evaporate out and the other liquid part not go away so fast? Why doesn't the water just evaporate too?

Thanks for your help!
 
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  • #2
Molecules of alcohol just exist somewhere in the air. Sooner or later they will react with oxygen.

Basically alcohol evaporates first because its boiling point is lower.
 
  • #3
bballwaterboy said:
Oh and lastly, why does the alcohol part evaporate out and the other liquid part not go away so fast? Why doesn't the water just evaporate too?

Who says the water doesn't evaporate?

When wine or spirits are put into oaken barrels for aging, a certain amount of liquid stored within is lost over time due to evaporation, and some of this loss unfortunately includes the alcohol. This lost portion is known as the 'Angel's Share':

http://en.wikipedia.org/wiki/Barrel
 
  • #4
As was mentioned already, the alcohol doesn't disappear. It will diffuse away as a gas.

Also, you will not evaporate ONLY the alcohol but a mixture of the alcohol and water which is enriched in alcohol due to the lower BP of the alcohol. At a certain point you will come to a mixture known as an azeotrope (http://en.m.wikipedia.org/wiki/Azeotrope) where no further enrichment will take place. This is for the case of ethanol/water, by the way. Not all mixtures form azeotropes but EtOH/water is a well known one.
 
  • #5
Borek said:
Molecules of alcohol just exist somewhere in the air. Sooner or later they will react with oxygen.

Basically alcohol evaporates first because its boiling point is lower.


Thanks everyone. So it does linger in the air then. Interesting. Thanks for explaining.

Quick follow-up: What'd you mean when you said that sooner or later it will react with oxygen? As in a "bad" way (like explode, etc.)?

Lastly, is it safe to use for cleaning around the house? My roommate uses it ALL the time in the apartment on his computer stuff and it has a strong smell to it (which can give me a headache at times).

He'll even use it in the bathroom (cleaning the toilet , counter, and floors with it) from what I've seen. Is this safe to do?
 
  • #6
bballwaterboy said:
Quick follow-up: What'd you mean when you said that sooner or later it will react with oxygen? As in a "bad" way (like explode, etc.)?

For the explosion you would need quite high concentration (google explosion limits). In general ethanol will get oxidized, first to aldehyde, then to acetic acid, finally to just carbon dioxide and water.

Lastly, is it safe to use for cleaning around the house? My roommate uses it ALL the time in the apartment on his computer stuff and it has a strong smell to it (which can give me a headache at times).

He'll even use it in the bathroom (cleaning the toilet , counter, and floors with it) from what I've seen. Is this safe to do?

I see no reason to worry. If it is giving you headaches, ventilate the room (or look for another roommate).
 

What Happens to Alcohol When it Evaporates?

Alcohol, such as ethanol, is a volatile liquid that can readily evaporate at room temperature. Let's explore the process of alcohol evaporation and its effects:

Q1: What Does it Mean for Alcohol to Evaporate?

Evaporation is the process by which a liquid, in this case, alcohol, changes from its liquid state to a gaseous state when exposed to air. This transformation occurs as the molecules of the liquid gain enough energy to break their bonds and become vapor.

Q2: Why Does Alcohol Evaporate?

Alcohol evaporates due to the kinetic energy of its molecules. The higher the temperature, the more kinetic energy the molecules possess, leading to increased evaporation rates. Additionally, alcohol molecules are relatively small and have weaker intermolecular forces compared to water, making them more prone to evaporation.

Q3: What Happens to Alcohol Molecules During Evaporation?

During the evaporation of alcohol, individual alcohol molecules absorb heat energy from their surroundings. As their kinetic energy increases, the molecules move more rapidly and eventually gain enough energy to overcome the forces holding them together in the liquid phase. This causes them to break away from the liquid's surface and enter the air as vapor.

Q4: Does Alcohol Evaporate Completely?

Alcohol can evaporate completely under the right conditions. However, the rate and completeness of evaporation depend on factors such as temperature, humidity, and the surface area exposed to the air. In open air or with sufficient airflow, alcohol can evaporate completely, leaving no liquid residue.

Q5: What Are Some Common Uses of Alcohol Evaporation?

Alcohol evaporation is widely used in various applications, including:

  • Cleaning: Alcohol is often used as a cleaning agent due to its ability to evaporate quickly and leave surfaces clean and dry.
  • Disinfection: Alcohol-based disinfectants and hand sanitizers use evaporation to kill bacteria and viruses on surfaces and skin.
  • Food Preparation: Alcohol is used in cooking to extract flavors from ingredients like vanilla beans. The alcohol evaporates during cooking, leaving behind the flavor.
  • Lab and Industrial Processes: Alcohol evaporation is utilized in scientific experiments, chemical processes, and the production of perfumes, pharmaceuticals, and cosmetics.

Q6: Can Alcohol Evaporation Be Dangerous?

Alcohol evaporation itself is not dangerous. However, it's essential to be cautious when using alcohol in open flames or high-temperature environments, as alcohol vapor is flammable. Proper ventilation should be ensured in areas where alcohol is used to prevent the buildup of vapor concentrations that could ignite.

Q7: Does Alcohol Evaporation Affect Alcoholic Beverages?

Alcoholic beverages can experience evaporation over time if not sealed properly. This can lead to changes in flavor and alcohol content. To prevent evaporation and maintain the quality of alcoholic beverages, it's essential to store them in tightly sealed containers and in a cool, dark place.

In summary, alcohol evaporates when its molecules gain enough energy to transition from a liquid to a gaseous state. The rate and completeness of evaporation depend on environmental conditions. Alcohol evaporation is commonly used in cleaning, disinfection, food preparation, and various industrial processes.

This FAQ provides insights into the process of alcohol evaporation, its uses, and

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