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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132 views

How many significant figures?

In Brown, Theodore E.; LeMay, H. Eugene; Bursten, Bruce E.; Murphy, Catherine; Woodward, Patrick; Stoltzfus, Matthew E.. Chemistry: The Central Science (Page 35). Pearson Education. Kindle Edition, an ...
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How do I dissolve sodium oleate in distilled water

I wanted to know how to dissolve sodium oleate powder in distilled water? Does it have to be at a certain temp? I need a 2% solution
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What is the difference between fractional freezing and fractional crystallization?

More simply put, what is the difference between freezing and precipitation when considering a mixture? Take two scenarios: First a mineral in water. If the temperature of this solution is lowered, ...
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Are complex ions thermochromic?

Does raising the temperature of a complex ion (formed from a transition metal ion and ligand(s)) affect its color? For example, if the temperature of $\ce{[Cr(H2O)6]^3+}$ is raised, will its color ...
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Why is there no standard temperature?

The standard state for a gas is defined at 1 bar of ideal gas. Why isn't there a corresponding standard state temperature?
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Why there is no one scale universal in measuring temperature? [closed]

a) Why we use Fahrenheit scale for measuring body temperature, Celsius scale for whether report, and for no use in daily life of kelvin scale it has importance in scientific calculations or in my ...
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Temperature dependence of molarity and molality

My textbook informs me that Molarity is dependent on temperature, whereas molality is not. I'm aware of the definitions of both molarity and molality, but consider this scenario: A solution of $\...
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The effect of temperature on the caffeine intensity

Does the brewing temperature have an effect on the caffeine level? For instance, coffee with 100*C have higher caffeine level compared to coffee with 50*C?
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Can we freeze water at −1 °C?

Is it possible to freeze water if it is directly exposed to $-1\ \mathrm{^\circ C}$ and not $0\ \mathrm{^\circ C}$? Is freezing point the minimum temperature at which a substance can be froze?
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What is the formula for evaporation rate of water?

I did my own research, and according to The Engineering Toolbox,the formula for the evaporation rate of water is as follows: $g_\mathrm h = \Theta A (x_\mathrm s - x)$ $g_\mathrm h$ = amount of ...
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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. ...