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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Large difference in boiling points of tetrafluoromethane and tetrachloromethane

Why is carbon tetrachloride $\ce{CCl4}$ is seen to posses liquid state (b.p. $\pu{76.72 °C}),$ whereas carbon tetrafluoride $\ce{CF4}$ is in gaseous state at room temperature (b.p. $\pu{−127.8 °C})?$
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The relationship between the temperatures at different times and pressures at different times is? [closed]

At the instant the boiling point is reached, the vapour pressure of the solution should be equal to atm. pressure. And since the boiling is continued the pressure will keep on increasing. Thus the ...
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51 views

The boiling points of Alkali metal group

As I know, the melting points of Alkali metals decrease down to the group due to decreasing of the energy of the metallic bond. But according to my understanding, after it has become to liquid the ...
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35 views

Boiling point elevation and liquid solutions

$\pu{1 L}$ of an aqueous solution of urea having density $\pu{1.06 g mL-1}$ is found to have elevation in boiling point $\Delta T_\mathrm{b} = \pu{0.5 °C}.$ If the temperature of this solution is ...
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Why does ammonia have higher melting point but lower boiling point than HF? [duplicate]

I guess the reason is hydrogen bonding, but shouldn't both the trends be similar in that case?
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Should High Vacuum oil smell?

I recently have purchased a high vacuum pump and am currently repairing it, the internals have a strong smell of oil. I was going to do an oil change anyway but should I clean all the old oil. High ...
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57 views

Change in boiling and freezing point

I recently encountered a question while solving previous year question papers for JEE. This is a JEE 2005 question. The question demands to complete this statement: Equimolar solutions in the ...
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289 views

Which one has the highest boiling point?

10 g of substance below were dissolve in each 1 L water: $\ce{Na2SO4}$ $\ce{NaCl}$ Glucose $\ce{MgCl2}$ Which one has the highest boiling point? Glucose has London dispersion force. $\...
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Why does chlorine gas have a higher boiling point than hydrogen iodide

Hydrogen iodide, $\ce{HI}$, is a dipolar molecule much larger than chlorine, $\ce{Cl2}$. The melting point of $\ce{HI}$ $(222.35\ \mathrm K)$ is definitely higher than that of $\ce{Cl2}$ $(171.6\ \...
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At boiling point, is the total pressure twice the atmospheric pressure? [duplicate]

We know that one definition of boiling point is that it's the temperature at which the vapor pressure is same as the atmospheric pressure. Assuming a closed container, does that mean that at this ...
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226 views

The Trend Between Boiling Point and Solubility in Organic Chemistry

Is it true in assuming that a higher boiling/melting point means that an organic compound will be more soluble in water? I'm trying to distinguish between the solubility of aldehydes vs. ketones ...
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How much salt (or any other substance one can find in a kitchen) do I need to add to make water boil at 104 °C?

I've seen some formulas around in other questions and Google searches, but my chemistry is pretty much dead so I have no clue where to find the relevant values to calculate it myself. I just need to ...
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48 views

Microscopic and mechanical approach to boiling point [duplicate]

I am confused as to how I should visualize the boiling process throughout a liquid. From my understanding, the boiling point of a liquid is when its vapor pressure reaches atmospheric pressure. This ...
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400–430 degrees Celsius heated bath

I want to perform a reaction which needs the temperature to be maintained between 400–430 °C. Since it's the only practical solution, I opted for a heated bath. I'm looking for a hydrocarbon fraction/...
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511 views

Why are the dispersion forces in CS2 stronger than the dipole-dipole forces in COS?

London dispersion forces supposedly have the least strength out of all the intermolecular forces. But $\ce{CS2}$, which has only dispersion forces, has a higher boiling point (and thus stronger ...
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552 views

Any examples of liquids volatile at room temp but non-flammable?

I'm thinking of something similar to the liquid used in the classic dipping birds. Temperature differential in two "bulbs" at each end of a tube should cause vapor to expand and push liquid to the top,...
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How long do I have to burn a carbon steel pan laced with flaxseed oil?

I've a carbon steel pan that's 26 cm in diameter, about 2 mm thick, but I doubt that it matters. I haven't been able to find a reliable resource that would tell me the smoke point of flaxseed oil, but ...
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Explain this boiling point order please [closed]

I read it from a book but don't know the reason. Please explain... Boiling point orders are - Ethanamide > Ethanoic Anhydride > Ethanoic Acid
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Size of hydrocarbons and boiling point

Increasing the contract surface area between hydrocarbons raises boiling point, so hexane should have a higher boiling point than propane. This doesn't really make sense to me. What is the difference ...
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281 views

Boiling point of ethanamide vs propanamide

I just have a question regarding the boiling points of some primary amides. Ethanamide has a boiling point of 222 °C, while propanamide has a lower boiling point of 213 °C. Both amides are capable of ...
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How to determine the boiling point of substances? [closed]

Which of the substances has the lowest boiling point? a) $\ce{H2O}$ b) $\ce{H2S}$ c) $\ce{H2Se}$ d) $\ce{H2Te}$ I've been searching for any formula or rule to determine this, but I read that it ...
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766 views

What effect on boiling and melting points does intramolecular hydrogen bonding have? [duplicate]

I know that intermolecular forces increase the boiling and melting point of a compound, but what is the effect of intramolecular forces on boiling and melting points? I found contradicting answers ...
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Is 99% Isopropyl Alcohol sold in stores really 99%?

My understanding is that an azeotropic mixture of isopropanol and water is 91%. This makes sense as to why there are so many brands of rubbing alcohol sold at 91%. There are also some sold as 99%, ...
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Why does increase in pressure cause a increase in boiling point [closed]

When we increase the atomospheric pressure pressure above the solution , the boiling point of a solution increases. Why does this happen?
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Boiling methanol in a microwave

Some protocols (metabolomics) use boiling methanol for metabolites extraction and cleaning glassware. Is it safe to boil methanol in a microwave?
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Is sodium hypochlorite 100% concentrate possible?

Popular bleaching brands like Clorox contain liquid sodium hypochlorite in small concentrations, ranging from 5-12.5% (is this a mass/volume, mass/mass, or volume/volume concentrate?). Is it possible ...
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Ionic factor of glucose? [closed]

I am trying to find the $K_\mathrm{b}$ for 50 g of glucose dissolved in 1 kg of ethanol, given the change in boiling point is $\pu{2.2 °C}$. The molality is therefore 0.278. But what is the ionic ...
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difference in boiling point of 2-iodopentane and 3-iodopentane

There is no difference in boiling point of 2-fluoropentance and 3-fluoropentane, so is chloro- and bromo-. But why is there a difference in the boiling point of 2-iodopentane and 3-iodopentane, up to ...
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Which solution has higher boiling point?

Between a 2% (w/v) aqueous solutions of $\ce{NaCl}$ and $\ce{RbCl}$, which will have a higher boiling point. Here there are two competing factors. First there's the fact that $\ce{NaCl}$ has a higher ...
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How can I determine the highest boiling point given a list of molecules? [closed]

I know that the highest boiling point has to do with which has the strongest intermolecular force. I also know that the strongest would be ionic, then hydrogen bonding, then dipole-dipole, then london ...
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Why does phosphine have a dipole moment and a higher boiling point than carbon tetrafluoride?

Phosphine, PH3, and carbon tetrafluoride, CF4, are small molecules of a similar size and the same mass of 88 au. CF4 has a dipole moment of 0, which is unsurprising given its tetrahedral shape. ...
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181 views

On what factors do melting and boiling points depend upon?

In my book there is a separate discussion given for trends in melting and boiling points in each chapter in inorganic chemistry (the chapters on the various groups like group 15, group 16, etc.) and ...
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539 views

Melting point vs Freezing point

Is it possible to have Melting point different that Freezing point I mean is there any element/molecule in the liquid status that freeze at point X Centigrade but when it become solid then you need a ...
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636 views

Are specific heat capacity and boiling point of a substance related or proportional to each other?

That is, if the substance has a high specific heat, will it also have a high boiling point? ( and vice versa)
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Boiling of a liquid [duplicate]

Consider water as an example. I m really confused when does boiling takes place. When it's vapour pressure equals atmospheric pressure or when it's saturation atmospheric pressure equals atmospheric ...
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Boiling point of water [closed]

I was doing an experiment on boiling-point of water and I was supposed to measure the temperature of the water when it boils, but I saw the there were droplets of water on the lid of the pot, and I ...
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Which chemical could be used to decrease water boiling point to a minimum possible level without heating it [closed]

I aim to decrease boiling point of water that will be used to generate steam. I wonder maybe there is an opportunity to add a substance that will help to decrease boiling point of water without ...
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311 views

PCl3 vs SCl2 boiling point

Why does sulfur dichloride have a lower boiling point than phosphorus trichloride? Is it to do with the higher number of electrons causing stronger id-id interactions in PCl3, or do we need to compare ...
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Reason for formation of bubbles at boiling point [duplicate]

As I understand it, boiling takes place when the saturated vapour pressure equals to the atmospheric pressure. But, why does the vapour pressure need to be equal to the atmospheric pressure for ...
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277 views

Molar entropy of vaporization

If a substance has a molar heat of vaporization of $\pu{3.05\times10^4J/mol}$ and a normal boiling temperature of $\pu{80.0^\circ C}$, what is the value of its molar entropy of vaporization $\Delta S_\...
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Explain the effect of intramolecular hydrogen bonding on solubilities in cold and hot water?

There is a statement given in my textbook (Cengage, Organic Chemistry (Part 1), page 4.33) which is as follows: (I edited the statement to make it simpler) One can account for the solubilities of ...
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Is it true that an evaporating molecule has the same kinetic energy as a molecule in a pot of boiling water?

A molecule on the surface of room-temperature water shoots off the surface of said water, or in other words, it "evaporates." It does so because it gained kinetic energy ${x}$, and ${x}$ was great ...
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233 views

Does sodium ethoxide (sodium ethanolate) have a boiling point, or does it decompose?

According to Wikipedia, $\ce{C2H5ONa}$ melts at 260°C, but no boiling point is given. What will happen if $\ce{C2H5ONa}$ is heated further?
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Find the boiling point of a compound given a pressure

I need to find the boiling point (in degrees centigrade) of ethanol on a day when the atmospheric pressure is $780\text{ torr}$. I know that the molar mass of ethanol is $46.07\text{ g/mol}$ but I ...
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Does the van der Waals force not affect the alkali metal 's trend of decreasing melting points down the table? [duplicate]

Melting and boiling points increase further down the halogen group, but they decrease further down the alkali metal group. I know that the former's trend has to do with the van der Waals force, but I ...
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Does boiling milk really make the nutrients in it less useful to the body when ingesting it?

Does “denaturing” nutrients in milk by boiling it make them less useful, or actually more useful, as they undergo “denaturation” anyway during digestion? I've read online that boiling milk "denatures"...
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Why does Xe have a higher boiling point than Ne? [duplicate]

I am certain that the reason involves intermolecular forces, but since both $Xe$ and $Ne$ are noble and non-polar gases, shouldn't these forces have a much smaller effect or negligible on boiling ...
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Why is the boiling point of para hydroxybenzoic acid lower than that of ortho hydroxybenzoic acid?

As per the literature at 760mm of mercury, p-hydroxy benzoic acid has lower boiling point ($\pu{336^\circ C}$ - ChemSpider) than o-hydroxy benzoic acid ($\pu{372^\circ C}$ - ChemSpider). What is the ...
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772 views

Why is the difference between the melting point and boiling point large for some compounds, and small for others? [duplicate]

I was looking at a list of melting and boiling points of various compounds and I realised some had very large differences while some have very less differences between their melting and boiling points....
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For a given period, why is the boiling point of the halogen greater than that of the noble gas?

The boiling point of bromine, a halogen, is $\pu{58.8^\circ C}$, while the boiling point of krypton, the noble gas in the same period as bromine, is $\pu{-153.4 ^\circ C}$. I thought that the larger ...