Alcohol and Water

alvin l nunley

alvin l nunley

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Question; does alcohol attract water?

Looking at the 2 pictures, you can see that there is an oxygen atom attached to one Hydrogen atom. I've been told by a chemist that the Oxygen atom wants to be bonded to 2 hydrogen atoms. There is a very strong attraction between the 2 atoms. If that oxygen atom is exposed to the air, and a hydrogen atom finds it and bonds do it, it becomes water H2O.

My chemist friend says; alcohol does not attract water, it attracts hydrogen atoms and becomes water.

The hydrogen atom, being the smallest atom on the periodic table, can get into places the water molecule could never get into.
 

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In order for the oxygen atom to connect with the oxygen and hydrogen, it must first break the bonds with the carbon atom.

Chemical reactions are either exothermic, or endothermic.
Meaning they give off heat, or require heat energy to complete the reaction.
 
95 shaw said:
In order for the oxygen atom to connect with the oxygen and hydrogen, it must first break the bonds with the carbon atom.

Chemical reactions are either exothermic, or endothermic.
Meaning they give off heat, or require heat energy to complete the reaction.
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If my memory serves me correctly, when Alcohol/methanol mixes with the water it is an endo reaction which is why it feels cool on your skin if you get it on you.

And just a clarification, endothermic doesn't necessarily need to have heat applied, but will pull heat from the area around it.
 
jaymancds said:
If my memory serves me correctly, when Alcohol/methanol mixes with the water it is an endo reaction which is why it feels cool on your skin if you get it on you.
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That cooling is the alcohol absorbing heat necessary to go from liquid state to a gaseous state. (heat of evaporation)
If you were to measure the temp, it stays steady until all the liquid requiring that particular temp is evaporated.
The temp would then rise to the next point of evaporation of the mixture.

This is the principle that a still operates on.
Catching the product of a particular range of distillation temperature produces the alcohol in a more concentrated version.

Water is distilled in the same manner.
 
Can anyone explain why plastic jugs of alky when not in a controlled environment (ie a hot trailer, left in sunlight or even left on the shop floor) sweat like crazy on the outside? And since moisture builds up on the jug is it safe to assume these jugs are also absorbing moisture?
 
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twostroketoowoke said:
Can anyone explain why plastic jugs of alky when not in a controlled environment (ie a hot trailer, left in sunlight) sweat like crazy on the outside? And since moisture builds up on the jug is it safe to assume these jugs are also absorbing moisture?
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A check of the temperature of the alky, and a reference of the dew point will give some insight.

If the jug is not sealed, moisture into the air is on the inside of the jug also.

I would say the jug is not sealed.

The air in the jug will reach the point of saturation, and the evaporation will stop, or be overcome by the condensation of the alky, effectively canceling the temp drop.

If the evaporated methanol escapes, the cooling continues at the heat of evaporation. If the energy is there, it will be absorbed.
This is also why a full jug absorbs less water than a almost empty jug.
Same thing applies to the fuel tank on your car.

Unlike gasoline, water mixes with methanol.
See water test for reference.
 
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Fill a glass with a cold liquid (preferably beer) and a dew forms on the outside of the glass. The higher the humidity in the room, the more due forms on the outside of the glass. Same thing with your alcohol container. If the container is tightly sealed, nothing gets in it.

When warm humid air comes in contact with a cold surface, the air is cool to it's dew point, the moisture falls out of the air onto the cold surface. "Falls out of the air" is not the precise thing that is happening. Go to Wikipedia for a better understanding of "due point".
 
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