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 melting point of Vanadium higher than Iron? [duplicate]

The iron is found to have four unpaired electrons while vanadium has 3 of them. we say the binding energy is directly proportional to number of unpaired electrons and hence number of metallic bonds ...
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Why does diethylmethylamine have such a low melting point?

According to PubChem, diethylmethylamine has a remarkably low melting point of $-196.0\ \mathrm{^\circ C}$. This is substantially lower than the melting points of dimethylethylamine ($-140.0\ \mathrm{^...
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Why the melting point increase up to arsenic and then decrease down the group 16? [duplicate]

I am already google this but can't find the answer that staisfy me. I know down the group, mass and atomic size increase which result in increase in van-der-waal forces. But in group 16 the trend is ...
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Melting point of objects and food

What is the melting point of egg yolk? Well, generally, when we break an egg, the yolk is in liquid state. After we pour it on a pan, the egg starts to cook and it hardens. My question is, can an egg ...
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Comparing melting points of substituted benzaldehydes

The correct decreasing order of melting point for the given organic compounds is: 3 has maximum melting point because of intermolecular hydrogen bonding. I am unable to predict rest of the order ...
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Can silicon dioxide melt at 20 °C?

Can $\ce{SiO2}$ melt at $\pu{20 ^\circ C}$? I have searched the web for $\ce{SiO2}$ phase diagram, but it seems to me that almost all the graph I can find have the temperature axis where the minimum ...
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Can Aluminum Hydroxide (Al(OH)3) be heated to it's melting temperature before decomposing?

On the wikipedia page for aluminum hydroxide the listed melting point is 300 °C (572 °F), but in the same page it states that aluminum hydroxide decomposes at only 180 °C (356 °F). Can aluminum ...
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Clausius–Clapeyron equation: shape of phase diagrams makes no sense

I am trying to model the melting point of a substance at varying pressures (ranging from very small to very very large). All I am trying to do is make an equation that relates melting temperature to ...
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Melting point of crystalline solids

Why crystalline solids have sharp melting points but melting point of amorphous solids vary within a range? Is it because the interaction energy is equal between atoms of crystalline solids so they ...
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How can we tell if a salt will melt or decompose?

Take $\rm NaCl$ for instance, a salt that will melt when it reaches its melting point, and compare it with $\rm NH_4NO_3$, a salt that doesn't melt, but instead decomposes to $\rm N_2O$ and $\rm H_2O$ ...
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Covalent Bonds and Ionic Bonds [duplicate]

Covalent bond is a strong bond compared to Ionic Bonds but Ionic Compounds have higher melting and boiling points then covalent compounds. Why?
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Mechanistic explanation of salt lowering temperature of ice slush

As we all know, adding salt to ice water lowers its temperature. I've read plenty of system-level accounts of energy balances, enthalpies, vapor pressures, phase equilibria and freezing points—I ...
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Why does strength of bond matter if melting only affects the the intermolecular of the molecules

So as I've been told, when a substance melts, the actual bonds of the substance aren't broken, only the IMFs (inter-molecular forces). So why is it that metal groups decrease in melting points going ...
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when Al2O3 melts which bonds are broken?

Previously, I was trying to understand why $\ce{Al2O3}$ has a lower melting point than MgO. An answer on quora said Do not confuse the character of the bond between the metal and oxygen with the ...
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Why does aluminum chloride have a higher lattice energy than aluminum fluoride?

From the table below (source: McMurry's Chemistry [1, p. 212]), it is evident that $\ce{AlCl_3}$ has a higher lattice energy than $\ce{AlF3},$ even though $\ce{F}$ is smaller than $\ce{Cl}$. Why is ...
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melting and boiling …really equilibrium? [closed]

Why are melting and boiling considered equilibrium processes even though the amount (concentration) of both phases keep changing i.e from solid to liquid and so on?
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d-Menthol vs dl-menthol: Does an enantiomer and its racemic mixture have different melting points?

I am checking out Wikipedia and it shows a different melting point (m.p.) for l-menthol $(\pu{42 ^\circ C}$ to $\pu{45 ^\circ C})$ vs dl-menthol $(\pu{36 ^\circ C}$ to $\pu{38 ^\circ C}).$ How 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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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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Pure gallium with lower melting point?

I melted about 2 kg of gallium and put it in a plastic container, in order to make crystals. After letting them grow and extracting them, I let the gallium freeze at the room temperature, which is ...
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Why does roasting requires lower temperature than melting point

Why do processes like roasting and calcination require a temperature lower than the melting point? Since intermolecular forces are lower in a liquid won't it be easier to oxidise (roasting) / ...
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How do scientists study liquid tungsten? [duplicate]

Inspired by this What If article: https://what-if.xkcd.com/50/ In the above article, Randall Munroe mentions that liquid tungsten is difficult to study because of its extremely high melting point. ...
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Freezing point vs Intermolecular forces

Water has a higher boiling point (100°C) than cyclohexane (81°C). This is probably because of stronger intermolecular forces between water molecules as compared to cyclohexane molecules. Then, why is ...
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Which has a high melting point, cocoa powder or cocoa butter?

I have been doing some research into chocolate, and after looking at the chemical compositions of cocoa butter and cocoa powder, struggled to determine which had a formula/structure that would have a ...
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Does melting HDPE plastic produce toxic fumes? (melting, not burning)

● The question isn't about burning HDPE but melting it at the proper temperature. (At 120 to 180°C depending on it's density, it becomes gooey. According to the source below the "extrusion" ...
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Question on Melting Points of Group 17,18 and 1

So , I have done some searching and found that melting points of groups 17 and 18 increase going down the group whereas group 1 decreases. However , the explanation seem to all be the same. Number ...
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Reasons for low melting point of gallium

J.D. Lee writes in Concise Inorganic Chemistry: Gallium has an unusual structure. Each atom has one closest neighbor at a distance of 2.43 Å. This remarkable structure tends towards discrete diatomic ...
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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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Melting point of aspirin, contradicting sources

Querying wolfram alpha for the melting point of aspirin (link) returns $\pu{140 °C}$. The Wikipedia page for Aspirin lists $\pu{136 °C}$ instead, citing this book. How am I supposed to know which ...
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Melting point in hydrocarbons

Checking out the molecular structure and the melting points of various hydrocarbons I concluded: 1)branching increases the melting point of a hydrocarbon molecule 2)symmetry increases the melting ...
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Is honey really a supersaturated solution? Does heating to un-crystalize redissolve it or melt it?

In the SciShow video Honey: Bacteria's Worst Enemy after about 00:30 the narrator says: Honey is only about 17% water. Most, but not all of what remains is sugar. ...
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Is there any sort of correlation between melting point and the degrees of freedom for the molecules of a substance?

Suppose I had a solid whose molecules did not have rotational freedom. But if I were able to make it so that the molecules had rotational freedom ceteris paribus, is there a way to tell how the ...
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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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Chemical that won't freeze below melting point

I have an organic chemical (can't say due to an NDA) that has a nominal melting point of 28 °C. When I raise it above this temperature, it melts, but then it will stay a liquid indefinitely at lab ...
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Why does substance that sublime not come to liquid state? [duplicate]

A substance that sublimates doesn't come to a liquid state at room temperature. But when we melt the substance it melts! Why does it skip the liquid state at room temperature?
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Melting point of unsymmetrical dimethylhydrazine vs 1,2-dimethylhydrazine

Unsymmetrical dimethylhydrazine ($\ce{H2NN(CH3)2}$) has a melting point of −57 °C, but its isomer, 1,2-dimethylhydrazine ($\ce{(CH3NH)2}$) has a melting point of −9 °C. That looks to me like a ...
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Where can I find reliable data for melting points of organic compounds?

I'm interested in the melting/freezing points of organic compounds, but the online literature has data that's all over the map. I can understand that especially for isomers of alkanes, pure samples ...
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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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Why does the temperature remain constant during freezing?

I know it's the most silly question one could ever ask but why is that so? I am aware of what latent heat means and I also know it has something to do with freezing too. Say I have with me, a mug of ...
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How does addition of impurities in a solid decrease the melting point? [duplicate]

In my textbook, it is written: The addition of impurities in a solid decreases the melting point of the solid. How does it do so? Why can't it increase the melting point?
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Comaparing melting points of group 14 elements [duplicate]

I found that melting point of $\ce{Sn(232°C)}$ is less than $\ce {Pb (327.5°C)} $ but i also saw that the bond enthalpy of $\ce {Sn-Sn(187.1 ±0.3 kJ mol^{-1})}$ is more than $\ce{Pb-Pb 86.6 ±0.8 kJ ...
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Melting of ionic compound hydrates

My professor asked us the reason of the melting point of potash alum being so low, despite it being an ionic salt. He later went on to answer it by saying that melting point is a misnomer for the ...
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Why is the melting point of iodine so high compared to ammonia? What about Zn and C(diamond)? [closed]

Increasing order of melting point by searching the temperature on the web: $$\ce{NH3} <\ce{I2} <\ce{Zn}<\ce{C_{diamond}}.$$ The idea I have read on "Chemistry: The Central Science" by ...
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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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Applying salt to roads to melt ice--is it special? [duplicate]

Most everyone is familiar with applying salt to the roads during winter to melt ice. I'm wondering if there's anything special about placing salt on the roads or would any other substance, sand for ...
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Why are highly branched alcohols solid?

Usually branching (or decrease in surface area) leads to increased volatility. But in case of alcohols, my book states that: The higher alcohols (butanols to decanols) are somewhat viscous, and ...
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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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Phantom Material: why formaldehyde doesn't rise my jelly melting point?

Just to be clear, I'm not a chemical but only a electronic engineer which want create a "phantom material" to reproduce the electrical characteristic of epidermis for the analysis of electrodes ...
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Melting point of trans-4-methylhex-4-enoic acid and cis-4-methylhex-4-enoic acid

My book said that the cis isomer has a higher melting point. But I dont understand isn't that the trans isomer can pack more efficiently, because the trans isomer less bulky/ create less 'kink' than ...
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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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