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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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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492 views

How would you measure the rate of this SN1 reaction?

I am performing the following $\mathrm{S_N1}$ reaction: $$\ce{t-BuOH + HCl -> t-BuCl + H2O}$$ I would also like to measure the rate of this reaction, but I cannot seem to find a way. I initially ...
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Has a concept of temperature ever been defined in the context of a single atom?

I wonder if this answer to What would happen if we supercool and then superheat an atom very abruptly? goes far enough. I almost wrote the comment: I don't think we can even talk about the ...
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80 views

Can this happen to superheated water?

Superheated water refers to water that is heating well beyond its usual boiling point under extreme pressure. This cause it to display anomalous property. I noticed that as temperature increases, so ...
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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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Formulations for wax thermostatic element for effect in alternative temperature range

Wax thermostatic elements are used automobile cooling systems and anti-scald mixing valves to control flow rates or to adjust mixing of flow inputs. These devices operate on the principle of thermal ...
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28 views

A formula for the refractive index of a gas dependent on temperature and pressure

I am in search for a formula that gives me the refractive index of a gas at a given temperature and pressure. Does such a formula exist? Ideally the solution should have this form: $n_g(t, p) = \...
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645 views

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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98 views

How could I find the solubility of hydrocarbons such as iso- and n-Butane in liquid Methane?

I am trying to figure out the dissolution capacity of iso and normal butane in methane at very low temperatures (110K). This would allow me to make compositions that prevent freeze out of these ...
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71 views

Target temperature for infused cooking oil

A little context: I make craft chili oils for friends and family. I use a two-step infusion process. First, I infuse the oil for flavor by simmering spices in the oil held around 250 degrees ...
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Non-conducting substance with a glass transition temperature around 400 to 600 °C?

Am looking for a substance to seel two pieces of ceramic that will have molten plastics flowing between at 300+ °C however silver solder circuit traces inside the device prevent me from going much ...
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431 views

Why is temperature considered as an important factor in deciding chemical reaction kinetics?

According to the Arrhenius equation, the rate of reaction is proportional to $e^{-1/RT}$. Here is a plot of the equation and its derivative with respect to temperature, both with respect to ...
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2k views

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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423 views

What is the explanation of the odd even effect in liquid crystals?

What is the most accepted theory for explaining the odd even effect in liquid crystals? Can anyone explain and refer the corresponding paper?
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600 views

heat capacity and thermal equilibrium

A $52\ \mathrm{g}$ piece of iron at $250\ \mathrm{^\circ C}$ is added to a mixture of $100\ \mathrm{g}$ of ice and $100\ \mathrm{g}$ of liquid water at thermal equilibrium $(0\ \mathrm{^\circ C})$. ...
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Thermochemistry: On Units of Enthalpy Change and Implicit Given of Initial Temperature of Calorimeter

I would like to ask two separate questions. But first, so that we are on the same page, the experiment used a constant-pressure calorimeter, and it is a neutralization reaction of 1M of HCl and 1M of ...
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58 views

Does fractionation use enough heat to destroy nutrients in Coconut Oils when seperating the MCT oils?

We have recently been giving MCT (medium-chain triglyceride) oil to our dogs in place of Coconut Oil as from what I understand the majority of the benefits of Coconut Oil comes from the MCT's ...
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How can we say that Helium (He) is liquid at “absolute zero”?

According to Wikipedia, Helium can never be solidified at $\pu{1 atm}$ ($\pu{101325 Pa}$) pressure, not even at absolute zero. A minimum of $\pu{25 atm}$ pressure is required to make Helium solid. But ...
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Adiabatic flame temperature of hydrogen peroxide calculation

I will first demonstrate my cursory method for evaluating the adiabatic flame temperature of H2O2 at atmospheric pressure. $$\ce{H2O2 -> H2O + 0.5O2}$$ At $\pu{1200 K}$, \begin{align} h_\ce{...
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Arrhenius equation using concentration

I've been conducting some experiments to determine the temperature dependence of a reaction. To do this, I've been conducting the experiments at different temperatures and generated a graph of $\ln{[\...
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22 views

Gas Law - increasing temperature with constant volume held

I've set up a simple experiment to look at the ideal gas laws. My experiment is relatively simple in that I have a metal tube which is capped on one side. I am then pressurising the tube with air to ...
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65 views

Derive expression for average heat flux in heat exchanger

The single-tube heat exchanger is used to increase the temperature of fluid I from $T_{b1}$ to $T_{b2}$. The heating oil (fluid II) used for this task enters at temperature $T_{02}$ and leaves at ...
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62 views

Freezing point lowering for a mixture of many liquids

I have been taught that if I have a solute of molality $m$ mixed with a liquid, the freezing point in lowered by an amount $K_\mathrm{f}\cdot m$ where $K_\mathrm{f}$ is the molal freezing depression ...
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Why do higher intermolecular forces lead to a higher change in temperature?

We performed an experiment in chemistry where tissue paper soaked in various chemicals was wrapped around the end of a temperature probe. The chemicals with stronger intermolecular forces had a lower ...
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55 views

How does Boudouard reaction influence the temperature?

I've a question that is giving me a lot of troubles: I'm depositing and gasifying Carbon by varying a flow rate of $\ce{CO}$ and $\ce{CO2}$ and by using the Boudouard reaction ($\ce{2CO -> C + CO}$)...
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Up to which temperature and pressure can dendrimers (PAMAM) be stable?

I am preparing PAMAM (poly amido-amine) dendrimer and I want to know up to which temperature and pressure can it be stable?
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Determining the acid dissociation constant change with temperature in sparkling water

I already have the different values of pH at the different temperatures, but what I'm trying to figure out is obtaining the acid dissociation constant using these pH values. Is there a way I can do ...
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171 views

How to evaluate enthalpy variation of combustion of sucrose in a constant volume calorimeter?

Consider combustion reaction (with the formation of $H_2O$ and $CO_2$) of a mass $m$ of sucrose in a constant volume calorimeter with thermal capacity $C$. This reaction increases the temperature of $...
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83 views

Silicone with good thermal conductivity

I am looking for a material with the same properties of silicone (flexible, easy to manipulate, soft, etc.) but without being a thermal isolate. I need this material to do the junction between a ...
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130 views

How to determine parameters range?

I am into running some leaching experiments and wanted to study the effect of different parameters on my dissolution results. But I am confused with determining the parameters range. For example, I ...
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103 views

Reaction rate in terms of temperature change

For exothermic reaction where concentration changed in hard to measure, can I interpret the rate of reaction in terms of temperature change? For example, if the experiment is iron rusting reaction ...
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124 views

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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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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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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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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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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190 views

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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564 views

Does freezing tights make them more durable?

Various blog posts and articles suggest that freezing a pair of tights will make them last longer. From a blog named Eclipsed Moon: Put your tights in the freezer. I thought that this was ...
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How can I use sunlight to heat a RBF and reflux a reaction?

This may seem like a off topic question but I really need help on it. I am currently working on a polymerization reaction in which I'm breaking down plastic polymers into smaller molecules. However, ...
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Melting temperature vs Isotropisation temperature in liquid crystals

What is exactly the difference between these two? I think melting point is when the compound melts down to visually liquid state but actually LC state and latter is when polymer becomes completely ...
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What is the equation that demonstrates the relationship between molar conductivity and temperature?

Can someone please help me find the equation that defines the relation between molar conductivity and temperature. I have found some information, but it was not really that much complete.
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How to resolve Amine Blush problems of a Epoxy curing Agent without having to change the temperature and moisture of the air?

The formation of Carbamate as a result of the reaction between amine groups of curing agents and H2O/ CO2 leaves the surface of the cured epoxy with some blurry lines and dots. the typical solutions ...
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Stability of Peroxynitric Acid in cold temperature

I have a question about the stability of Peroxynitric Acid i.e. $\ce{HO2NO2}$ at cold temperature. I know that it becomes stable when temperature decreases, but what is the specific reason for it? I ...
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272 views

Why doesn't a temperature and pressure gradient exist in a container of real gas?

In the Kinetic theory of gases, it is assumed that there are no intermolecular forces between the atoms/molecules. But real gases, have intermolecular attractive and repulsive forces. Suppose a ...
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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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Can I freeze water at 100 °C if I add 28 grams NaCl in 100 grams water?

Can I freeze water at 100 °C if I add 28 grams NaCl in 100 grams water at 20 °C? I found this diagram that says, if I have 28.05 wt% NaCl in water, then the equilibrium temperature between two phases ...
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Temperature required for E1 elimination reaction

I wanted to ask what's the temperature required for carrying out elimination reactions? Wherever I read about elimination reactions, they just mention that elimination reactions occur at high ...
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Can the melting / freezing / boiling points of a molecule be calculated dynamically?

I'm just starting to self-learn about chemistry. Lets say we know the atoms that make a molecule and their structure. From that information alone is there any single formula that can dynamically ...