Questions tagged [temperature]

A measure of the average kinetic energy of the particles in a sample of matter; may be expressed either in kelvin (symbol K) or in degree Celsius (symbol °C).

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288 views

Liquids that keeps the lowest temperature for the longer time after being frozen

I am working on a personal project, however I know nothing about chemistry and I would like to ask you guys for a quick question. I need to use a liquid for my project, which after being put into a ...
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Evaporation Rate of Water

In AP Chem we did a lab investigating the relationship between vapor pressure and water temperature. The relationship is linear and as the vapor pressure approaches atmospheric pressure, it begins to ...
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Is there a structured data source containing information on the World Health Organisation's Stability Testing Policies?

Hoping to automate some product testing guidance software, I've been attempting to find a (hopefully live, up-to-date) Database, Web-service, or other structured data source containing the ...
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Regarding Kw, titrations, and pH

So I have need of performing a titration upon a fruit juice to determine acid concentration. I will be using 1M NaOH as my base. Seeing as the solution will be coloured, it would be difficult to use ...
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Does boiling water alter the chemical properties of dishwashing liquid?

An ex-housemate of mine claimed to be a former chemist, and once told me not to use boiling water (or recently boiled water) when leaving dishes to soak, as the temperature would chemically alter the ...
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What causes mercury to expand equaly unregarded what the temperature increase is?

Mercury seemed to be a good liquid to use in thermometers. But why are most liquids expanding non-linearly with increase of temperature compared to other liquids?
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Is there a way to counteract the problems with weighing hot objects?

I am currently performing an experiment in which it would be greatly beneficial to be able to accurately measure the mass of a hot object without waiting for it to cool. The current plan is simply to ...
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Metaphosphoric acid and water in cold

Consider this redox reaction: $$\ce{3PCl3 + 2HNO3 (conc.) + 5H2O → 2NO + 3[HPO3] + 9HCl}$$ The metaphosphoric acid is taken in square brackets, because I have doubts about it. As I know, this ...
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Unable to find sources for uncommon specific heat

I'm calculating the energy, temperature, and gas volume outputs of gunpowder. To solve this I need to find the specific heat of Potassium sulfate (K2SO4) and Potassium carbonate (K2CO3). If anyone can ...
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Parameter effects on kinetics of esterification for bio-diesel production

I want to discuss the effect of parameters on the kinetics of esterification for bio-diesel production. In esterification process, temperature effect and molar ration are two important parameters. ...
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Is temperature just the phenomenon of particles colliding against an object?

This is just something that I thought up while doing busy work at my job. Is the sensation of heat simply coming from particles colliding with your, say, hand? Are they transferring energy more to ...
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Is the final temperature of a solution affected by the order of mixing components?

For example, I have two beakers each containing water. One is at 90 $^{\circ}$C and one is at 10 ${^\circ}$C. Will the final temperature of the solution I make from mixing the two components be ...
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Latent Heat and Kinetic Energy

The kinetic theory says that temperature is the measure of the average kinetic energy. That would mean then: The temperature rises with the rise in kinetic energy. We know that when matter changes ...
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At what temperature does carbon dioxide decompose into carbon and oxygen? [duplicate]

If you were to super-heat a mole of carbon dioxide gas, at what point would it decompose into carbon and oxygen? If it decomposes into carbon monoxide and oxygen, at what point do those products ...
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What is the lowest temperature tungsten starts sublimating at?

What is the lowest temperature tungsten starts sublimating at? I've tried to search in Google but without any luck. For example, $\ce{WO3}$ starts sublimating roughly at $\pu{550 °C}$, according to ...
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Why are some organic reactions run at elevated temperatures?

We are using a water bath at $70\ ^\circ\mathrm{C}$ for different reactions to identify oxygen-containing organic compounds, such as the Tollens reaction, the iodoform test and hydroxamic acid test. ...
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Supersaturated gas solution

Can you make a supersaturated gas solution? As we know solubility decreases when we increase the temperature, So If I do that, will the gas molecules escape the solution or will they stay in the ...
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Safe endothermic reaction that gets below freezing?

I have a project/idea I am working on but I am only 14 years old and I need some help. I'm looking for an endothermic reaction that gets below freezing, but the chemicals before the reaction and ...
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How accurate would be the following conclusion on 'Critical Temperature'?

"Boiling does not occur when liquid is heated in a closed vessel. On heating continuously vapour pressure increases. At first a boundary is visible between the liquid and vapour phases because liquid ...
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The temperature rise after neutralisation

The answer to this question is B, however, I don't quite understand. If considering Q= mc delta T, the heat released is to some extent being influenced by the no. of moles. If using that line of ...
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How does iceskating work?

I was willing to understand a little bit better the physics behind iceskating. Messy thoughts From New Scientist (1964) (probably not the most up-to-date reference $\ddot \smile$), I found a diagram ...
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Why is −78 °C a magic temperature for organic reactions?

In many organic reactions that I have seen, running the reaction at $\mathrm{-78\ ^\circ C}$ seems to be quite a popular choice, but I've never seen any explanation for this. What makes this ...
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Can 0-Carborane be stored at room temperature?

I am a physics post-doc at Oak Ridge National Lab (with a bit more training in chem than the average physicist). I ordered a small sample of o-Carborane from Sigma-Aldrich to test for doping liquid ...
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Entropy as “extent of energy dispersal” vs. entropy as defined by the Clausius equation

Currently, the concept of entropy as "energy dispersal" has been proved to be more easy to understand than the concept of "disorder". While the first can be applied successfully to explain the ...
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Liquification of gas to liquid at critical temperature

The gas that liquifies first, when cooled from 500 K to its critical temperature given in parenthesis is a) $\ce{CO2}$ (304.1 K) b) $\ce{NH3}$ (405.5 K) c) $\ce{O2}$ (154.3 K) d) $\...
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Non-Ideal Gas Behavior

I obtained measurements of temperature and pressure at various temperatures ($-10, 0, 20, \text{ and } 50^\circ \mathrm{C}$) and plotted them on a graph. Projecting backwards, the best-fit line ...
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How do I control the negative temperature in an experiment?

If one were to adjust the positive temperature in an experiment, they would use a heating plate, or a stovetop. How would one adjust negative temperatures in an experiment? (Not keeping the ...
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Is there a chemical reaction that speeds up when the temprature gets lower?

We were talking about chemical reaction speed on our chemistry class, and I asked my teacher if there is a chemical reaction that speeds up when the temprature gets lower? I think this is not everyday ...
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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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Resultant temperature of mixture

**Question: ** There are 2 flasks of equal volume, connected by a narrow tube of negligible volume, filled with nitrogen gas. When both are immersed in boiling water, the gas pressure inside the ...
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Which temperature to subtract from which when calculating a difference? [closed]

Is $\Delta T$ solved by using: $T(\mathrm{final})-T(\mathrm{initial})$? Or $T(\mathrm{initial})-T(\mathrm{final})$? I am getting some conflicting info from class and online.
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Stability of CN molecule

The $\ce{CN}$ molecule has been observed spectroscopically in comets where pressure has been estimated to be as low as $10^{-10}\ \mathrm{mmHg}$. Draw a Lewis structure for $\ce{CN}$. Suggest an ...
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Does the initial rate in the reaction of magnesium powder with nitric acid depend on the volume or the concentration of the acid?

For the question regarding the initial reaction rate, I don't quite understand why the answer is D. If I calculated the number of moles from the volume and conc, I would get A=0.4 moles; B=0.2 moles;...
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What is the meaning when it is said “Temperature of an Oxyacetylene Torch is 3500 degrees Celsius”?

I don't think flame is anything but the product at that temperature but I am not sure. What exactly is flame? And I think the correct statement should be that the exothermic reaction here produces ...
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Liquid nitrogen superheating with a layer of oil?

edit: Thanks Ivan, also further research. Pure water can be superheated to a few degrees above 100 degrees. However I remember reading reading that water can be superheated to even higher ...
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Peak Wavelength of Emission Spectrum of a Flame vs. Actual Flame Temperature

I am looking at a lab test of two variants of mixed hydrocarbon gas (57.8% $H_2$, 16.9% $N_2$, 12.4% $CH_4$, 1.11% water vapor, and 11.8% "unknown" gases) burning in oxygen which shows a discontinous ...
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Why is the Haber process carried out at such high temperatures?

On a large scale, ammonia is prepared via the Haber process: $$\ce{N2(g) + 3H2(g)->2NH3(g)} \qquad \Delta _\mathrm{f}H^\circ = -46.1~\mathrm{kJ \cdot mol^{-1}}$$ The optimum conditions for the ...
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what contributes to the temperature of a vacuum [closed]

what is the temperature of Vacuum since temperature of a system is related to the average of the molecular kinetic energy and there is no molecule in a vacuum? i know there could be radiations but i ...
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When is a reaction feasible at room temperature?

Gibbs free energy determines whether a reaction will occur spontaneously or not. Still, the activation barrier of a reaction determines if a reaction will occur at a given temperature. At any non-zero ...
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At which temperature does carbon monoxide explode?

I had doubt whether carbon monoxide explodes or not. I checked out this resource and found out that carbon monoxide explodes when heated. But they didn't mention the temperature at which it explodes. ...
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Does an increase of area lead to more collisons in a confined jar of gas?

I'm reading a lecture by Richard Feynman in which he is talking about the behaviour of gas molecules/atoms within a confined vessel. The confined vessel is a cylinder with a piston to stop the water ...
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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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Increase in Yield of products in an exothermic reaction [closed]

Given an exothermic reaction $\ce{N2 + 3H2 -> 2NH3}$ (which was initially in equilibrium). The temperature is then increasing with time. I am supposed to predict the yield of ammonia with time. ...
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When it is said 'at constant pressure, at constant pressure ', is it about pressure & temp. of the system or surroundings?

These are the following statements: [...] the thermal decomposition of $1.0$ mole $\ce {CaCO3}(\text{s})$ at $1$ bar results in an increase of volume of nearly $90~\text{dm}^3$ at $800^\circ \text{...
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Heat capacity during state change

I read that the heat capacity of water when it is at 100 °C or 0 °C is infinite because all the heat given to it will not be used to increase temperature but to change the state. I am unable to ...
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Pressure change of a gas upon increasing the temperature

My assignment is as follows: A sample of air is trapped in a container at 16.2 psi. If the initial temperature is increased from 10°C to 32°C, what is the final pressure? I am really confused as ...
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Why does melting point depend on external pressure?

The melting point of a substance is the temperature at which the solid form's vapor pressure equals the liquid form's vapor pressure. I read that the vapor pressure of something depends ONLY on the ...
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Why does the Temperature Decrease?

This is from a calorimetry lab. $50\ \mathrm{ml}$ of acid and base were mixed. Why does the temperature keep decreasing after 1 minute and why isn't at a constant rate? Is it because heat is lost to ...
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At what temperature do complex hydrocarbons become ashes?

When heating a metal tube with polypropelene in it, i found that i still had brittle black foam and flakes in it even though it had been in a blue flame at around 500'C What happens to complex ...
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Which phase is more efficient for temperature changes?

In the case of attempting to heat and cool down an object of different states, if you in some case managed to achieve the same temperature of a solid, liquid and gas what state would scientifically ...