Quote:
Originally Posted by vstech
antifreeze has little to do with the boiling point protection.
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Incorrect. Freezing point depression and boiling point elevation are colligative properties and are solely due to the presence of other molecules/ions/atoms being dissolved in water. If you dissolve ANY substance in water it will both lower the freezing point and raise the boiling point.
Quote:
Originally Posted by vstech
higher pressure caps boil water at a higher boiling point.
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Correct. The phase diagram of water (and every other substance I can think of) reveals that the boiling point increases with system pressure. The exact relationsip is described by the Clausius-Clapeyron equation.
Quote:
Originally Posted by vstech
the water wetter products reduce the water particles and make it absorb heat faster... keeps the motor cool.
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"Wetter" water has surfactants present that lower the surface tension. This increases the efficiency of the heat transfer from the metal to the water.
Quote:
Originally Posted by patbob
Hydrometer tests amound of dissolved stuff in coolant. Freeze and boil temps are dependant mostly on that. As vstech points out, pressure held by cap is predominant boil temp control.
Corrosion protection is via chems in antifreeze, and they get used up over time, hence the periodic repacement.
Expect corrosion protection to degrade nearly independently from hydrometer reading.
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Correct.
Quote:
Originally Posted by shertex
If I wanted to test corrosion protection, how would I do that? With one of those little strips?
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I am not aware of any product that will do this. Measuring the specific gravity with a hydrometer will not. You would need to identify what compounds are the corrosion inhibitors and then measure their concentration.
Quote:
Originally Posted by Biosudds
I believe he means that the anti-freeze reduces the hydrogen bonding between water molecules, which actually does reduce their size.
Generally the high boiling point of water and its high heat capacity is due to the hydrogen bonding between molecules. However, Tango, you are correct that the addition of antifreeze increases the boiling point of water. This is due to the colligative properties of mixtures and the fact that anti-freeze has a higher vapor pressure than water. The addition of anti-freeze increases the overall boiling point, despite reducing the hydrogen bonding of the water molecules.
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Incorrect. Hydrogen bonding is the major component of water's large heat capacity but does not explain the variation in boiling point (or freezing point) with the addition of anti-freeze.
Incorrect. Anti-freeze does not significantly alter hydrogen-bonding.
Incorrect. The size of these molecules size does not appreciable change because of the presence or absence of inter-molecular forces from other molecules.
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04-14-2011, 04:34 PM
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