New answers tagged phase
8
It is a problem of phase.
The standard entropy of butane is $\pu{310 J mol-1 K-1}$ in the gaseous phase.
The standard entropy of hexane is $\pu{296 J mol-1 K-1}$ in the liquid phase. But it is $\pu{389 J mol-1 K-1}$ in the gaseous phase. So the entropy increases from butane to hexane in the gaseous phase, as expected.
10
There are two factors to consider. Certainly, the dominant factor is that the degrees of freedom available for the molecule to disperse energy into increases as the carbon chain extends. Thinking along these lines, one would expect a monotonic increase of entropy with carbon chain length.
However, we must also consider phase. As the carbon chain increases in ...
2
The question: $\pu{1kg}$ of a solution of cane sugar is cooled and maintained at $\pu{-4 ^\circ C}$. How much ice will separate out if molality of solution is $0.75$?
Given: $K_\mathrm{f} \text{ (Water)}= \pu{1.86 K kg/mol}$
The solution is given assuming you understand the concept. It seems you did not completely understand the colligative properties of ...
3
There is really not much to it. Basically you have a metal and an oxide phase, and never the twain shall mix significantly even after melting the oxide above 2000°C [1]. The suboxide that is sometimes mentioned, $\ce{Al2O}$, is not indicated here.
From Ref. 1
Reference
1.
S. Das, "The Al-O-Ti System", J. Phase Equilibria 23(6) (2002), 525-536.
6
Ionic liquids have very special properties, the most important of those of interest is that they are liquids at low temperature with extremely low vapour pressure. This is in fact the main reason they have caused excitement among chemists. Quoting (1) from a report comparing the volatility of various ILs:
An extremely low vapor pressure (e.g., ca. 100 pPa ...
7
Ionic liquids are not magical liquids. They are just typical organic compounds with certain properties. These compounds generated a storm in the tea cup in the late 1990s and 2000s, but they are as toxic as other solvents. Certainly they have niche applications especially as a gas chromatography stationary phase, where they can be used at high temperature (...
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