Questions tagged [melting-point]
The melting point of a solid is the temperature at which it changes state from solid to liquid.
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Why is heptadecane referred to as a solid if its melting point is below standard ambient temperature? [closed]
Heptadecane's melting point is $22^\circ $ and standard ambient temperature is $25^\circ$, but online I see that heptadecane is marked as a solid. Why is that?
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Dipole-dipole vs London dispersion forces for deducing melting and boiling points
To determine the melting and boiling points of compounds, London dispersion forces are typically compared. However, why are the polarity and dipole-dipole forces ignored?
For instance, $\ce{HI}$ has a ...
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Phases in equilibrium and not in equilibrium
What is the difference between the phases of a substance in equilibrium or not in equilibrium? For example, at room temperature, water is a liquid. It is also a vapor above the liquid formed from the ...
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Anomaly in boiling point as compared to melting point in d-block [duplicate]
Consider the following graph:-
In the above graph, it can be observed that the melting point of Chromium is higher than that of Vanadium (though there's not much greater difference despite the fact ...
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Why is the melting point of copper higher than gold which in turn is higher than silver?
In a d-block group, as we go down, the effective nuclear charge increases. The increase in effective nuclear charge would in turn result in greater strength of metallic bonding. So as we move gown the ...
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Was an accepted answer wrong in using the word "maximum"?
Melting and boiling points of transition elements
It was asked:
The melting and boiling points of transition elements increase from
scandium (1530 ∘C ) to vanadium (1917 ∘C ). They increase because ...
user151937
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Question regarding enthalpy of sublimation vaporization and fusion
While learning Thermochemistry, I came across the formula
$\Delta H_{sub} = \Delta H_{vap} + \Delta H_{fus}$
Now my question is how that when we want to change the phase of a substance from solid to ...
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Does gunpowder (black powder) melt when heated?
I was just watching a video about yellow powder (similar formula to black powder, but with potassium carbonate instead of charcoal), and I was wondering:
Does regular black powder melt (and ...
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Why DMSO has much higher freezing point than DMF (19 °C vs -61 °C)?
Recently, while solvent optimization of a reaction, I found DMSO froze in an ice-bath but DMF didn't.
From Wikipedia, I found out that DMSO (dimethyl sulfoxide) has a freezing point of 19 °C (ref. 1) ...
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Why does pectin/agar jelly taste sweet, if they stay solid at 36.5 °C, entrapping sugar?
When we eat pectin jelly(fruit jelly) or agar jelly, they taste sweet.
This should imply that sugar entrapped in gel network is somehow exposed and dissolved to saliva.
However, pectin and agar gel ...
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Melting Point Order of Benzene Derivatives
Q)Compare the melting points of the following?
o-Hydroxybenzaldehyde
o-Methoxybenzaldehyde
p-Hydroxybenzaldehyde
p-Methoxybenzaldehyde
My attempt: Intermolecular H-bonding increases melting point ...
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Melting point of sulfur
The melting point (m.p.) of rhombic sulfur is 385.8 K while the m.p. for monoclinic sulfur is 392 K. Also, the transition temperature of rhombic to monoclinic sulfur is 369 K.
Now, consider heating ...
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Wide temperature range fluids
I am investigating various fluid power compounds for use at high temperatures. I am seeking a material that is liquid around room temperature, or melts at under 300 C, but that remains a stable liquid ...
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Alkali-rich lead glass with working range at room temperature
I understand that the glass transition temperature (above which it is considered a super-cooled liquid) is quite far below the liquidus of the corresponding crystalline mixture. In the paper, "...
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Why is that during a phase transition, a single melting point exists for melting?
I know that during melting, latent heat is used in increasing potential energy (as intermolecular distance increases) of the complete structure of given solid to liquid. But it can also happen ...
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What explains the relative order of melting and boiling of oxygen and nitrogen?
Why is the melting point of nitrogen ($\ce{N2}$) greater than that of oxygen ($\ce{O2}$)? After all, both are non-polar, and $\ce{O2}$ has more electrons than $\ce{N2}$.
In addition, why is the ...
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How would you explain the general trend in melting point between Group 1 and Group 2 chlorides?
This question is based off of the attached chart. I notice how there's a general increase in melting point down group 2 chlorides and a general decrease (except for Lithium) down the group 1 chlorides....
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Why exactly does copper have a higher melting point than zinc?
It is said that copper has a higher melting point than zinc because of the d electrons in copper being involved in metallic bonding. However, copper has no unpaired electrons in its d subshell just ...
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Why is the melting point of meta-diiodobenzene higher than that of ortho-diiodobenzene?
I'm currently trying to reason for as why the melting point of meta-diiodobenzene higher than that of ortho-diiodobenzene and I'm unsure of what to say. I understand the para isomer has the highest ...
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Neopentane melting point [duplicate]
Given that neopentane and n-pentane are both hydrocarbons derived from pentane with five carbon atoms each, but differ in their structural arrangements — with neopentane being more branched and n-...
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Why does the melting point of hexafluorosilicic acid differ that much in these two solution concentrations?
From the Wikipedia article for hexafluorosilicic acid:
Melting point:
ca. 19 °C (66 °F; 292 K) (60–70% solution)
$<$ −30 °C (−22 °F; 243 K) (35% solution)
What's the reason for this huge ...
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Why does Cr have higher melting point in the 4 period among the transition metal? [duplicate]
There is a lot of answer stating that the low enthalpy of atomisation in Cr is due to the reason of partially filled d orbital, thus having extra stability. This makes the orbital more attracted ...
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Melting point of various solids: should strength of ionic bond make ionic solids the highest melting [closed]
Arrange the following in the increasing order of melting point of different types of crystalline solids
covalent solid
metallic solid
molecular
ionic
According to me the arrangement should be:
ionic ...
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Why do Mn and Tc have lower melting points with respect to their immediate neighbors but Re doesn't?
Manganese (Mn) and technetium (Tc) show a sharp decline in their melting point in comparison to the neighboring transition elements, which is unexpected while following the general trend which says ...
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Lower melting points of zinc, cadmium and mercury
I am aware of the fact that d-block elements like zinc, cadmium and mercury have lower melting points than other d-block elements. Also I am aware that these three metals have a fully filled d shell.
...
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Making a super-eutectic
A eutectic system is a mixture of substances which has a lower melting point than any of it's components. For example salt to melt ice. Also, a eutectic has the right mixture of components so that it ...
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Comparing melting point of neopentane and butanol
Why does something like 2,2-dimethylpropane have a much higher melting point than butan-1-ol?
I know that butan-1-ol has a hydroxyl group, and is capable of hydrogen bonding, and I know that 2,2-...
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How to calculate the freezing point of an equimolar ethanol: water mixture using colligative properties [closed]
I am familiar with how to calculate the freezing point of a mixture with a 9:1 molar ratio of ethanol to water (see below). I can understand that ethanol, having a higher mole fraction, is considered ...
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Melting and boiling point of transition-metals, primarily for the groups of Cr and Mn [duplicate]
The NCERT Chemistry book for Grade 12 writes
The high melting points of these metals are attributed to the involvement of greater number of electrons from $(n-1)d$ in addition to the ns electrons in ...
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Extent of Melting of Bonds or Intermolecular Forces
I'm currently having a revisit on the subject of periodicity of the periodic table, and I came across an issue that is kind of bugging me.
If we take a look at the melting and boiling point trends of ...
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Interpreting Ternary Phase Diagram Stoichiometry
I am trying to locate the lowest-melting mixture in a system of three nitrate salts: sodium, potassium, and calcium nitrate. I have the relevant ternary phase diagram, but I am unsure exactly about ...
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What easily accessible material has melting point between 500 °C and 590 °C?
Is there an available at home material with the melting point between 500 °C and 590 °C?
Plastics usually melt below 400 °C.
Tin and lead also below that.
Aluminum is melting above 600 °C.
I made a ...
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What is the difference between milk and cream that causes disparate result when freezing and thawing?
If you freeze milk and then let it thaw/melt again you just need to shake and it is more or less indistinguishable from unfrozen milk. That is not true for cream - after letting frozen cream (40 % fat)...
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lowest melting point of alkali salts [closed]
I want to make the alkali metals sodium and potassium through electrolysis of molten salts. However, I only have the ability to heat stuff up to about 260 degrees Celsius.
What would be the lowest ...
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Boiling and melting points of hydrocarbons [closed]
What happens while boiling and melting hydrocarbons? Which bonds are broken?
When we compare the boiling point (b.p.) and melting point (m.p.) of certain hydrocarbons the order is inverted. For ...
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What happens to the sea of electrons when a metal melts/boils? [closed]
I was taught about metallic solids with the sea of electrons model. My question is how does the sea of electrons function when metal turns into a liquid and a gas. The way I see a liquid is ...
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By how much does borax reduce the melting temperature of gold?
I'm researching ways in how to salvage gold from old electronics. I think I got the process down but I have one question. When you have salvaged the gold from the electronics you are left with gold ...
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How can steel be so different from iron, even if amount of carbon is small?
Perhaps I am too naive, but I am having a hard time visualizing how even 'high-carbon' iron and steel alloys are maybe, at most, about four percent carbon by mass, which still means only one (smaller) ...
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Why does fcc lithium melt with increased pressure?
According to the phase diagram of lithium given here, the fcc phase formed at moderately high pressure melts at decreasing temperature upon adding more pressure, an effect better known with the ...
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The melting and boiling point decreases down the group up to group 14 (not including transition metals), but the trend reverses from group 15. Why?
In groups 1, 2, 13 and 14, the melting and boiling point decreases down the group with a few exceptions. In group 15 the melting/boiling point increases up to Arsenic and then started decreasing. In ...
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Why is the thermal stability of calcium carbonate higher than that of magnesium carbonate even though lattice energy decreases down a group?
The difference in thermal stability of $\ce{CaCO3}$ and $\ce{MgCO3}$ can be explained using Fajans' rules, but why not using the lattice energy method?
Why is the thermal stability of $\ce{CaCO3}$ ...
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What are some of the lowest melting point glasses available out there?
I'm wondering about lead-free "glass solder" or any glass frit powder or paste that has a very low melting point (under 400 c). What products are available to the layman, where can I find ...
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Why there is not a consistent pattern between the carbon chain length and the melting point of fatty acids? [duplicate]
I looked at the melting temperature of different saturated fatty acids and I expected to see that with a longer chain of carbon the melting point would be higher as after all the var der Waals ...
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Methanol-water mix freezing points - clarify contradictory online data > 60% w/w?
Extending an exploration of windshield washer-fluid choices to freezing points of methanol-water mixes, all web-sources located agreed to within a couple of degrees from 0-60% w/w, yet above this ...
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Why is the melting point of magnesium nitride less than that of beryllium nitride?
Why is melting point of $\ce{Mg3N2}$ lower than that of $\ce{Be3N2}$ ?
I have two reasonings:
The lattice energy of $\ce{Be3N2}$ is higher than that of $\ce{Mg3N2}$ so accordingly the melting point ...
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Why is there no exothermic crystallization peak visible during cooling of PLA and no endothermic melting peak visible during a second heating of PLA?
I am doing lab research on DSC measurement (Heat-cool-heat) for understanding melting characteristics of polymers (PLA, PA6 and PE). During cooling i saw exothermic peak and during second heating i ...
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What happens if you superheat timber in a zero oxygen environment? [duplicate]
I was thinking to myself, what would happen if you were to put a lump of wood in a zero oxygen environment and superheat it? It couldn’t burn because fire needs fuel, heat and oxygen however because ...
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Compound with pressure sensitive melting point at moderate temperature and pressure
I'm in need for a compound with ideally all of the following properties:
A melting point of 5 °C or less at 1 atmosphere (or slightly lower pressure)
A melting point of 12 °C or more at less than 20 ...
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Crucible design for melting alumina
I'd like to melt alumina in a slow, controlled manner.
So I thought a graphite crucible with a tungsten wire wrapped around it for heating would be a good start. To reduce heat losses, I put that ...
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Comparing of melting point of dibromo p-xylenes
How to compare the melting points of the above isomers? I know that melting point depends upon the packing of the molecule, more efficient the packing, higher is the melting point. Symmetry in a ...
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