# Tag Info

7

The problem is, we want to see a trend in everything. There are various factors that govern melting point and boiling point which is the reason of perceived anomalies. "The equation which has more number of variables, is harder to solve." For melting point, few of them are: Crystal system, size of atom, atom-atom distance, distance between two ...

7

According to Wikipedia, ethanol flash point is $\pu{55 ^\circ F} = \pu{12 ^\circ C}$. Auto-ignition temperature is $\pu{793 ^\circ F} = \pu{423 ^\circ C}$. It means that ethanol vapor cannot be put on fire with a match at a temperature under $\pu{12 ^\circ C}$. But its vapor will not spontaneously ignite at temperature lower than $\pu{423 ^\circ C}$.

3

If you heat the commercial concentrated ammonia solution ($25$% $\ce{NH3}$) at usual pressure, it will boil at $32$°C and the vapor contains $3$% $\ce{H2O}$ (and of course $97$% $\ce{NH3}$). So the liquid looses much ammonia and nearly no water. Its total volume decreases a bit but the concentration of ammonia decreases more, so that it is necessary to heat ...

2

But my source of confusion is that ambient pressure is not the only pressure pressing down on the liquid. Pressure does not press down. When something is under pressure, it exerts it in all directions. Maybe it would help imagining this problem in the absence of gravity (you would have to put the sample in a stretchy balloon to get some pressure while being ...

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