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 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 ...
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How can HCl be liquid if it has a boiling point at -85°C?

Shouldn't it at least be boiling? When water reaches its boiling point it makes bubbles, but that doesn't happen with HCl, why? Did I misunderstand some basic chemistry?
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Is there a relationship between boiling point and van der Waals constants [closed]

Is there a relation of the boiling point of a gas with its van der Waals constants, $a$ & $b$? I know if constant $a$ is greater, then the boiling point will also be greater, because of more ...
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Why does acetonitrile have a larger dipole moment and boiling point than acetaldehyde?

Experimentally, acetonitrile has a larger dipole moment than acetaldehyde, but I've never understood why. I always thought that the charge separation between carbon/oxygen is larger than that of ...
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Why do alkanes have higher boiling point than their ether counterparts?

Based on my understanding of inter-molecular forces, I expect dipole-dipole interactions to be significantly stronger than van der Waal's interactions. Hence, I expect ethers (which obviously have ...
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Boiling point trend in group 13

My Theory: Since atomic mass increases down the group, the van der Waal's forces should also operate to a greater extent, thereby making it difficult to change the phase of the substance. Hence, ...
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How to compare the boiling point of water, ammonia and hydrogen fluoride?

According to the values of boiling points that I found on internet the order is as follows: $\ce{H2O}$ > $\ce{HF}$ > $\ce{NH3}$ I was expecting $\ce{HF}$ to have highest boiling point because F ...
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Why is the boiling point of polonium less than that of tellurium?

My textbook states that polonium has a lower boiling point than tellurium because it has weaker intermolecular forces of attractions (van der Waals forces). Why are van der Waals forces of attraction ...
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Enrichment of D2O

The Wikipedia page for deuterium oxide (heavy water) says that its boiling point is 374.5 K and the one for ordinary water is 373.13 K. Is there a way of distillation which we can use to enrich ...
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Lowering the boiling point of wax

Wax comes in all kinds (paraffin, bee wax, palm oil wax, gel wax, ...) but since it's usually a mixture of different carbonated chains, its physical properties vary a lot from one manufacturer to ...
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When boiling a liquid, how vapour pressure and ambient pressure get equal? [duplicate]

When boiling a liquid, how vapour pressure and ambient pressure get equal? As vapour pressure will increase, it will lead to increase in ambient pressure also. let, Initially there would be some ...
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General organic chemistry [closed]

What is the correct order of boiling points of the following compounds ? 1) butanol 2)butanal 3)butanoic acid
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Boiling point of alkynes from n = 2 to 10

From a video on organic chemistry, I found this table that shows the boiling point temperatures of alkynes $\ce{C_{n}H_{2n-2}}$ with $\,n=2...10$. $$\begin{array}{|c|c|c|c|} \hline n & t_\mathrm{...
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Why is the boiling point of hydrogen sulfide higher than that of hydrogen chloride?

The boiling point of $\ce{H_2S}$ is higher than $\ce{HCl}$. Is this due to the greater number of hydrogen bond that $\ce{H_2S}$ can form compared to $\ce{HCl}$? I found this explanation for the ...
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Chemical bonding [duplicate]

How do we compare the strength of permanent dipole permanent dipole (PDPD) interaction? Is it by bond polarity? Since H-X (where X is halogen) is polar, and for bond polarity (PDPD bond strength): ...
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Do mixtures have a boiling point?

Let's assume a mixture which can be heated without decomposing. This site explains that while pure substances have a sharply defined melting point and boiling point, mixtures tend to have a melting ...
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When comparing boiling points of two ionic compounds, what bonding factors should you assess?

When comparing boiling points of two ionic compounds, should you look at their electronegativity difference, lattice energy, or strength from LDF forces (or all 3 factors)? For example, between LiCL ...
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Is my proof valid for the formula of elevation in boiling point? [closed]

Is my proof valid for the formula of elevation in boiling point? proof By Clausius clayperon equation, $$\ln(P)=-\frac{∆H_v}{RT}+c$$ Differentiating, $$\frac{dP}{...
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Solid with Boiling Point less than 100 °C [closed]

For an experiment I require a substance which is a solid at room temperature and boils at a temperature lower than 100 °C. Also, this solid should preferably be soluble in water. Are there any such ...
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Confusion over boiling point of gallium

I am completing a project on gallium, and I need to include its boiling point. I thought that this would be fairly simple to look up, however, it appears that different sources quote different ...
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Can someone explain me the difference in boiling point of water when I add: KBr; CaCl2; AlCl3?

I have noticed (during an experiment) that the boiling point of the solutions created by H2O+KBr; H2O+CaCl2 and H2O+AlCl3 see their boiling point increase. During the experiment, I thought that, ...
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Polarisability of alkynes, alkenes and alkanes

I have noted a little trend in the boiling points of alkynes, alkenes and alkanes. Upon searching for the explanation, I have chanced upon an answer written by M.A.R. (Alkane, Alkene, Alkyne boiling ...
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Ordering compounds by boiling points

Here is a MC question from my chemistry professor: What is the correct order of boiling points for molecules: $\ce{CO2}$, $\ce{LiOH}$, $\ce{CH3OH}$, $\ce{CH2O}$? I am mainly confused about ...
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How do I know how many molecules a solute will split into when it dissolves in a solvent?

I'm in high school and I'm learning about freezing point depression and boiling point elevation. I've been given this chemistry problem: Acetic acid has a boiling point elevation constant of 2.93 ...
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How does hydrogen bonding affect the boiling points of chemical compounds?

My main question is why is the boiling point of methanol so much different from that of water? I understand that both compound are able to develop hydrogen bonding, and obviously water can develop ...
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How do foundries prevent zinc from boiling away when alloyed with Aluminum?

How do foundries prevent lower boiling point metals such as zinc from boiling away when alloyed in a furnace with higher boiling point metals such as aluminum?
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Boiling points of Hydroxylamine and water

Why does $\ce{NH2OH}$ have a lower boiling point than water? According to Wikipedia, hydroxyamine has a boiling point of 58 °C. Could this be due to the extent of hydrogen bonding among both molecules?...
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What are the boiling points of DMSO-water concentrations?

What are the boiling points of DMSO-water concentrations with respect to wt% DMSO? I have found extensive information on the freezing point change of wt% DMSO but nothing regarding boiling.
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Why does AsF3 boil at 60.4 Celsius and AsF5 at -52.8?

I don't understand why the boiling point of $\ce{AsF3}$ is at 60.4 degrees Celsius and $\ce{AsF5}$ boils at -52.8 degrees Celsius. I understand that it has to do with the bondings, but I can't see ...
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Why do alkenes with more surface contact have greater London forces?

Why is it that alkenes with greater surface contact have greater London forces? I thought greater London forces were dependent on the size of the molecules, or the number of electrons, rather than the ...
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The Boiling or Evaporation of Diethyl Ether

When we heat water, we see bubbles appear as the boiling point approaches. The water then "boils" vigorously as it is converted from the liquid phase to a gas. I realised recently that during an ...
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Real boiling temperature

I've been thaught that water at 1 atm water boils at 100 °C (the so called “normal boiling point”). However, I came across a more rigorous description of the boiling process saying that in order to ...
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Calculating Boiling Point of solution

I wish to calculate the boiling point of the following solution. (w/w) 78.8% Glycerol, 11.6% Propylene Glycol, 8.3% Water, 1.2% Nicotine (molar fraction) 0.5790 Glycerol, 0.1037 Propylene Glycol, ...
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Need help interpreting this data table (provided below)

I am confused about this data table. Can someone please explain how this person got a linear alkanes of differing molar masses? (I know some basics of organic chemistry, but I'm still learning.) Are ...
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Is using melting/boiling point good to measure volatility?

I wanted to figure out a way to compare volatility in organic compounds, so I read on many forums on the differing ways to measure volatility, which included enthalpy of vaporization and melting/...
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Phase Diagrams and Equilibrium

In this link http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch14/phase.php It says (in the latter part ) that for all combinations of Pressure and Temperature along line BC the rate of ...
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Can somebody help me understand this sentence?

"The molar enthalpy of vaporisation of a liquid is the enthalpy change when one mole of the liquid changes into one mole of its gas at the boiling temperature." The part which i am not sure of is the ...
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Boiling point comparison between cyclohexane derivatives

I am trying to order these according to boiling point. I think that B is the highest because it has hydrogen bonding. I am not sure how to differentiate A and C though. They both have about the same ...
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Boiling Point trend

Why does group 13 and 14 show reverse the trend of boiling point? In other groups, boiling point increases down the group but here it decreases.
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IChO problem involving the condensation point of NF3, NHF2, NH2F

This is a problem from the 2016 International Chemistry Olympiad (IChO): Which of $\ce{NF3}$, $\ce{NHF2}$, and $\ce{NH2F}$ condenses at the lowest temperature? The answer book says that it is $\ce{...
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how to determine the volatility of an organic compound using the physical properties of organic molecules

How do you tell if a compound has a high volatility? Also can the boiling point of a compound be taken into consideration when determining if a compound has a high volatility?
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Lewis Structure of Fe4(SiO4)3

I'm a first year university student and am working on a paper regarding factors that affect how far an asteroid will penetrate into the Earth's atmosphere before exploding. One of the factors I came ...
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Throwing water into lava

While discussing magma in class with my students, I showed a video of a man throwing water onto molten, running lava. A large flame ensued. I realize that the water is being converted into steam and ...
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Does fumaric acid form stronger hydrogen bonds than maleic acid?

My book claims: Fumaric acid can form intermolecular hydrogen bonds (strong) while maleic acid forms intramolecular hydrogen bonds (weak), hence fumaric acid has higher boiling point than maleic ...
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Why do alkyl chlorides have lower boiling points than the corresponding alkyl bromides and iodides?

To my knowledge, the $\ce{C-Cl}$ bond is stronger than the $\ce{C-Br}$ and the $\ce{C-I}$ bond. I always thought that the stronger a bond, the harder it is to break so the boiling point would be ...
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Is varnish with a flash point above 40 celsius safe in a microwave oven?

I've painted regular white mugs and want to varnish them too. But my varnish has the following specs: Gloss varnish based on alkyd resin. Flash point: Above 40 degrees celsius. Is it safe to ...
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How can a substance have a higher boiling point but lower melting point than another substance?

Looking at 1,3-Butadiene and Isoprene, I'm wondering: why does Isoprene have a higher boiling point, but a lower melting point than 1,3-Butadiene? I'm thinking this might be because the Methyl group ...
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Boiling point elevation for a mixture of ethanol and water

Properties such as boiling point, freezing point and vapour pressure of a pure solvent change when solute molecules are added to get homogeneous solution. These are called colligative properties....
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Is it correct to say that SOME iodine undergoes sublimation at 1 ATM

The triple point of Iodine occurs at 0.12 atm and at standard temperature it is a solid on the phase diagram. I understand that therefore, when heating iodine at 1 atm, it (at least some of it) will ...