Questions tagged [boiling-point]

The boiling point of a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid

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Why is the boiling point of stibane higher than that of ammonia?

I recently came across the fact that the boiling point of $\ce{SbH3}$ (stibane) is greater than that of $\ce{NH3}$ (ammonia). I was expecting $\ce{NH3}$ to have a greater boiling point as a ...
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Can I make a container of (kind of) perpetually boiling water?

It's a common school experiment to make water boil at room temperature by putting it in a container and reducing pressure. I am wondering if it is possible to make a sealed sphere containing water ...
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Is there a liquid that looks like water but boils at a low temperature? [closed]

I just watched a movie where someone put their hand into boiling water. Disregarding how this was actually done, I wondered whether there was a liquid which could be used for an illusion of someone "...
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Confusion about boiling point and vapor pressure [duplicate]

It is said that a liquid boils when its vapor pressure equals to the external pressure of its environment (e.g. atmospheric pressure). That’s because the bubbles of water vapor that form will be ...
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As we go down a fluoride-alkali metal series, why doesn't the boiling point decrease?

As you can see from the graph below, as we go down the blue fluoride-alkali metal series (alkali metal ion is varied from Lithium to Rubidium, which is represented by an increase in ionic mass on the ...
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Why o-Nitrophenol is more volatile than p-Nitrophenol? [duplicate]

Why o-Nitrophenol is more steam volatile than p-Nitrophenol?
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What are the factors affecting Boiling Point in Ions?

I understand that for molecular substances, intermolecular forces such as van der Waals forces and hydrogen bonding are the major factors effecting the boiling point. However, I am not sure about ...
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Hydrogen bonding in alcohols vs amines

Consider an alcohol and an amine compound with roughly the same molar mass. If I understand correctly, the boiling point for the alcohol is greater for two reasons: The $\ce{O-H}$ bond is more polar ...
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What determines the boiling point of esters of the same number of carbon atoms but different structural formula?

The boiling point of esters increases with molecular weight (and therefore, number of carbon atoms) because of more dispersion forces. But if you had two different esters with the same number of ...
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Why is the boiling point of m-dichlorobenzene less than that of p-dichlorobenzene?

Why is the boiling point of m-dichlorobenzene less than that of p-dichlorobenzene? Shouldn't the former have a higher boiling point because it possesses a dipole moment? I think the van der Waals ...
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The effect of pressure on boiling point?

My textbook states the following: Qualitatively, I understand why the boiling point of a substance increases when the pressure is increased. However, I learned that if the pressure is increased when ...
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Physical properties of phenols

Order of increasing boiling point is p-nitrophenol > m-nitrophenol > o-nitrophenol. The difference between bp of p- and o-nitrophenol is that one form intermolecular hydrogen bonding while other form ...
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Boiling Point Reversal

If substance A boils at a lower Temperature than substance B under atm. pressure, can it be that under some other condition, say, elevated Pressure or under vacuum a reversal of the trend occurs? i.e....
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Why is the boiling point of alkyl iodide is more than alkyl fluoride?

As far as I know, more the polar character of the organic compound, more will be the energy required to break the bond and thus more boiling temperature. Here in this case, $\ce{R-F}$ is more polar in ...
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Why is the boiling point of a solution higher than that of a pure solvent? [duplicate]

Why is the boiling point of a solution higher than that of a pure solvent? I think when a non-volatile solid solute is added to a solvent, some of the liquid solvent molecules are replaced by solute ...
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Boiling point of: Halogenoalkanes vs alkanes vs alcohols

We know that Boiling point (alcohol) > Boiling point (halogenoalkane) > Boiling point(alkane) with same number of $\ce C$ atoms, but is the following, good explanation of that?: Since e.g. $\ce{...
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Melting and boiling point trend in Group II

The following picture shows the melting and boiling point trends down group II elements. I have added question marks where the variability in data was rather disturbing (over two hundred degrees ...
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Vapor pressure, volume and boling point

The saturated vapor pressure is designated as the gas pressure in a closed container when the evaporation process has reached an equilibrium (when there are as many molecules returning to the liquid ...
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1answer
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Is this Boiling point apparatus?

I have some chemistry equipment but I am not sure what it is for; I think it may be apparatus for measuring elevated boiling points. I have included a drawing of how I think it should go together. ...
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1answer
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Heating of mixture of gases with one gas barely above its boiling point

What happens when mixture of two gases is heated in a closed container? If one gas expands faster than the other and increases pressure of the container enough so that the boiling point of the other ...
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1answer
830 views

Why is the boiling point of rectified spirit lower than alcohol absolute?

The boiling point of rectified spirit is ($78.1~\mathrm{^\circ C}$) while that of absolute alcohol is ($78.3~\mathrm{^\circ C}$). I know its too small, but shouldn't the addition of impurities ...
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1answer
288 views

How to separate benzyl alcohol and meta-cresol

Benzyl alcohol and meta-cresol boiling point's are not so different, the fractional distillation will be very difficult, what can i do for separate this two composites ?
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Dissociation of H3PO4 and colligative properties

Which of the following solutions that have concentrations of $0.01\ \mathrm{M}$ show the highest elevation in boiling point and why? A) $\ce{NaCl}$ B) $\ce{CaCl2}$ C) $\ce{H3PO4 }$ D) $\ce{...
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Why do alcohols and ethers have approximately the same solubility in water but different boiling points?

In Morrison & Boyd, I found this question: Butan-1-ol (b.p. $118~\mathrm{^\circ C}$) has a much higher boiling point than its isomer diethyl ether (b.p. $35~\mathrm{^\circ C}$), yet both ...
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Elevated boiling points in alkanes with even number of carbons [duplicate]

Why do alkanes with even number of carbon atoms have greater boiling points than those with odd number of carbon atoms?
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Does a freezing point of a substance always increase as its boiling point increases?

I am studying for an introductory to physical sciences test and came upon a chart describing substances found in petroleum and the distillation process. Each freezing point increases as each boiling ...
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How to determine what organic molecule has the highest boiling point?

Compare and answer which one has the highest boiling point: $\ce{CH3CH2CH2CH3}$ (butane) ... [$\pu{−1}$ to $\pu{1^\circ C};\ 30$ to $\pu{34^\circ F};\ 272$ to $274\ \pu K$] $\ce{CH3NH2}$ (...
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Colligative properties

I have some problems with these properties. 1) Lowering vapor pressure and boiling point. It happens because the solute molecules take space in the surface of the liquid so a lower number of the ...
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Why is the boiling point of sulfuric acid much higher than that of phosphoric acid?

Why is boiling point of sulfuric acid much higher than that of phosphoric acid? According to the data book, • The boiling point of sulfuric acid is 337 °C (639 °F; 610 K) When sulfuric acid is ...
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Boiling and Exploding Beaker?

A few days ago, I was creating a solution which involved boiling water. I had two 4L beakers on identical hot plates. After around 10 minutes, the first one boiled. Waiting another 30 minutes, the ...
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Boiling point and vapor pressure

Does a liquid having higher vapor pressure have a lower boiling point? I think so because I read in wikipedia that, "A substance with a high vapor pressure at normal temperatures is often referred to ...
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percent dissociation

Would these answers be correct? . Of 100% of the NaCL molecules dissociated, the Van't Hoff factor i, would be equal to 2 for NaCl. We assumed it equaled two when we figured out Kb of the NaCl ...
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What is the boiling point and density of LSD?

I have tried to do a lot of research and didn't succeed to find the boiling point and density of LSD. I would want to know this information. In addition, I can't use Clausius–Clapeyron equation ...
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What is the temperature at which lava evaporates?

According to this article -> http://ntrs.nasa.gov/search.jsp?R=19660041998 Lava evaporates under natural conditions, but apparently, only a little bit. I'd like to know the temperature at which ...
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Why does CO2 have higher boiling point than CO?

The intermolecular forces between $\ce{CO2}$ molecules are dispersion forces, while the forces between $\ce{CO}$ molecules are mostly dipole-dipole attraction forces. So, why does $\ce{CO2}$ have a ...
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Why does chlorine have a higher boiling point than hydrogen chloride?

Chlorine has a boiling point of $238~\mathrm{K}$ while hydrogen chloride has a boiling point of $188~\mathrm{K}$. Hydrogen chloride has dipole-dipole forces so I would expect it to have greater inter-...
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Trend in the boiling point of the hydrogen halides

The boiling points of the hydrogen halides are as follows: $$\begin{array}{cc} \hline \text{Species} & \text{Boiling point / }\mathrm{^\circ C} \\ \hline \ce{HCl} & -85.1 \\ \ce{HBr} & -...
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Why do chlorinated silanes have lower boiling points than their methane analogs?

The boiling points of the chlorinated silanes and methanes are given below: $$\begin{array}{ccc} \hline \text{Species} & \text{Boiling point (X = Si) / }\mathrm{^\circ C} & \text{Boiling ...
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Why is the boiling point of CH3COOH higher than that of C2H5OH?

Why is the boiling point of $\ce{CH3COOH}$ higher than that of $\ce{C2H5OH}$ ? Both are polar molecules held by hydrogen bond.
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Why do the boiling and melting points decrease as you go down group 1 and vice versa for group 7?

I used to think that because an alkali metal needs to lose one electron to complete its outer shell, when the atom increases in size (atomic radius), the electron would be easier to lose as the ...
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boiling point and distillation relation

i need help with the fractional distillation method of a couple of substances at least more than two substances , just like air actually what am i looking for is that why do substances in air with a ...
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At what temperature (in kelvin) are most of the elements on the periodic table liquids?

This question is out of pure curiosity. At what temperature are a majority of the elements on the periodic table in a liquid state/phase of matter? For the purpose of this question, assume the ...
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How are the boiling points of Tungsten and other metals determined and proved?

The boiling point of Tungsten is 10,030 degrees Fahrenheit. How was this determined and proved? And more generally how are the boiling points of metals determined and proved? Is it really so simple ...
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What is the connection between vapor pressure and intermolecular force explanations of boiling?

I've had boiling explained to me in two ways, and I'm having trouble understanding how they connect. The first way is that a liquid is held together by the intermolecular forces, and boiling involves ...
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Why do the melting points of Group 15 elements increase upto Arsenic but then decrease upto Bismuth?

The boiling points of group 15 elements increase on going down the group (or, as size increases) but the same is not true for the melting points. The melting points increase from $\ce{N}$ to $\ce{As}$ ...
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Why is CH4 a gas at room temperature but CH3Cl a liquid?

I cannot figure out a question on my review sheet. The full question is: Methane ($\ce{CH4}$) is a gas at room temperature but chloroform ($\ce{CH3Cl}$) is a liquid. Explain why changing just one $\...
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1answer
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What [if anything] is special about the boiling process of purifying water (excluding temperature)?

I know that water boils at $100~^{\circ}\rm C$. I also know that the standard way to purify water is to boil it for roughly a minute. What I'm curious about is, what properties of the boiling process ...
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What is the correct order of boiling points for group 15 hydrogen compounds? [duplicate]

What is the order of boiling points of the following $\ce{NH3}$, $\ce{PH3}$, $\ce{AsH3}$, $\ce{SbH3}$ and $\ce{BiH3}$? What I thought was, that as $\ce{H2O}$ has a higher boiling point compared to ...
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How can you boil milk without causing it to foam and overflow?

I have looked at this Why does milk overflow... But I've not found a solution to prevent the milk overflowing. I remember reading (cannot recall the source) that in industries where milk is boiled a ...
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Melting and boiling point comparison

Graphite, silica and diamond are covalent compounds and still they have high melting and boiling points. Why?