Questions tagged [viscosity]
Viscosity refers to the 'thickness' of a fluid as well as its resistance to shear and tensile stresses.
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Data sheet for the dynamic viscosity of salt-water-glycerol solutions
Does anyone know where I can get data for the dynamic viscosity of salt-water-glycerol solutions? Specifically 80% glycerol and 20% salt water by mass at 19.2 degrees celsius. Salt concentrations vary ...
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How to Choose the Appropriate Spindle and RPM in Rotary Viscometer for Viscosity Measurement of a Suspension Sample?
I am currently conducting a method validation for the analysis of a suspension. This would be the first time we will be conducting viscosity analysis via rotary viscometer and the below statements are ...
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Are all humectants sticky?
While using a topical lotion based on ethanol, water and propylene glycol, I noticed that it becomes sticky while drying. Propylene glycol is a humectant and is used for this purpose in ...
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IAPWS-IF97 empirical equations for water and steam
IAPWS-IF97 provides empirical equation the dynamic viscosity and the thermal conductivity for water, are there any formulas by IAPWS-IF97 for the density and the specific heat capacity of water?
I ...
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Details of what actually happens in cold sulfuric acid between 80 and 90%; what molecular changes cause the viscosity to skyrocket?
AChem's answer to Why does the graph of the electrical conductivity of sulfuric acid/water solutions have this knee in the ~85%-~92% range? includes this plot from Horace E. Darling in "...
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How to make a paste out of vinegar?
I am trying to make a smooth vinegar cream for short term use of up to about 3 months (i.e. no preservatives are needed if stored in a cool place).
Vinegars such as apple cider vinegar or pure acetic ...
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Viscosity and repulsive forces
Suppose we let a ball move in a fluid with initial velocity $u_i$. Then as time goes on its velocity goes down and tends to $0$ after infinite time. I understand viscosity in the following way:
In ...
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Data on Vapour Pressures of Silicone Oils [closed]
I am trying to find specific information on vapour pressure of silicone oils with different viscosities which I have used in some experimental work. Is there a chemical databook where this information ...
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Density and Viscosity for Solution: 80% Liquid Methane CH4 with Solution of 20% Gas Nitrogen N2 on Surface of Titan (the largest moon of Saturn)?
Problem:
Need to estimate the density and dynamic viscosity of such a mixed fluid: 80% Liquid Methane CH4 with solution of 20% Nitrogen Gas N2 with temperature of 94K and pressure of 1,467 hPa (the ...
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What does it mean to "shear" an emulsion?
The following instructions are given for a preparation and I am wondering what it means to "shear an emulsion"?
The water phase components and the oil phase components are each mixed
in ...
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higher viscosity base oil instead of better lubrication results in worse
UPDATE:
The problematic "symptom" that I try to fix, is the static friction of two sliding plastic parts.
This is about a keyboard key switch that was made during the 80s. The problem/issue ...
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Viscosity at CMC
What happens to viscosity at critical micelle concentration? Does it increase or decrease abruptly, and if so, what's the reason behind it?
I'm aware of changes in other properties such as ...
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Precise estimation of air properties as a function of temperature at 1 atm
Are there any tables with empirical equations to calculate properties of air as a function of a temperature at 1 atm?
For example, NIST provides such equations for a large number of gases, but I was ...
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What is the viscous component in viscoelastic materials? [duplicate]
All real solid materials are in certain way viscoelastic, because an ideal fully elastic material doesn't exist as well as a fully viscous solid material. According to rheologic models it is possible ...
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Dynamic viscosity of gas mixture (appropriate estimation)
What estimation of the dynamic viscosity $\eta = f(T)$ $([\eta] = \pu{Pa·s})$ of the gas mixture components would you recommend during adsorption at a low temperature, approx. $\pu{293 K}$ to $\pu{333 ...
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Difference in collision cross-section obtained by measurement method
I have a simple question of Physical Chemistry, but I don't know the answer.
We can find collision cross-section(σ) through experiments in three ways.
first, diffusion flux experiment. diffusion ...
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How to turn oil into in a gel?
I've seen some EPR experiments where they add gelatin to water with spin-probes in it, as it "hardens" it immobilizes the spin-probes so that you can check effect of tumbling rate on the EPR....
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Additive for water to increase the viscosity to a value between 5 and 20 cP [closed]
Is there an additive that I can add to water that will increase the viscosity to a value between $5$ and $\pu{20 cP}$? Ideally, I would like the mixture to be newtonian and since I will be working ...
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Calculating the viscosity of water using particles
There are two particles with radius 0.212 μm. The particles are in a thin liquid film and the microscope can only detect movement in the $x$- and $y$-axis. The temperature is 25 °C.
$$
\begin{array}{c|...
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Does motor oil get more viscous when heated & what is the meaning of the SAE motor oil code?
The motor oil in my 2004 Pontiac Vibe is 5W-30.
My (incorrect) understanding of this SAE nomenclature is that 5W means "Viscosity index of 5 in the winter" (or when really cold - like $\pu{-30 ^\...
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Gas / Gas mixture dynamic viscosity temperature and pressure dependance
I’m trying to get an accurate interpretation of certain gases ($CO_2$, $N_2$, $NO$, etc.) dynamic viscosity [Pa.s] as a function of temperature and pressure (afterwards determine the dynamic viscosity ...
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How to modify viscosity of ZnO ink?
I have stumbled upon these instructions on how to create $\ce{ZnO}$ nanoparticles.
I am interested in making a DIY ink, for use with a parallel metal plate pen and a piezo-actuated microdrop nozzle.
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Why is the viscosity of water and ethanol lower than that of a water-ethanol mixture?
We found in an experiment using Ostwalds method that
ethanol is more viscous than water, which
is already surprising as water has stronger intermolecular bonds than ethanol as @MaxW pointed out.
The ...
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Is there a correlation between acidity and viscosity of honey? [duplicate]
I was wondering if honey's viscosity has any correlation with its acidity and if not, it would be very helpful if anyone could tell me what variables could affect the viscosity of honey?
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Effect of pressure on viscosity of liquids and gases [closed]
My textbook says the following on viscosity and pressure:
increase in pressure decreases the viscosity of water but for other liquids it increases. Viscosity of gases does not change much
No ...
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Properties of starch in packaged pudding
I had a mug of packaged pudding. The top layer of the pudding was of typical pudding consistency, while the bottom was more runny. What could have caused this?
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Do solids flow? [duplicate]
I am now confused whether solids flow or not. Some people say solidity is only a time scale notion. Some others say solids do not flow at all. While some authors say there is a threshold stress below ...
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Why does the viscosity of honey decrease when mixed with other viscous fluids?
In order to make honey mustard, I mix honey and mustard. But the resulting mixture is less viscous then both honey and mustard. How does mixing two viscous substances give a less viscous one?
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Viscosity and concentration of solutions
I will need a fluid around a specific viscosity, using a mixture of water and something like sugar.
Is there a way to calculate viscosity based on concentration?
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Two common fluids that don't mix inside a labyrinth [closed]
I'm not sure in which SE site put this question.
Imagine a typical child toy, where a bunch of spheres move by gravity through a labyrinth.
Now imagine a sealed small labyrinth with two fluids. I'd ...
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Looking for a non-volatile liquid less viscous than water
I have tried searching everywhere for a stable, non-volatile, bio-safe, low viscosity (< .8cST) fluid. Everything I have come across that is low viscosity is inflammable - acetone, ether, silicone ...
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What kind of chemical reaction happens when combining Tahini and Date syrup?
While both Tahini and Date syrup are quite thin, when mixed together they form a paste-like substance that is very delicious, and quite thick. But what kind of chemical reaction leads to such sudden ...
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Thickening and/or slowing evaporation of IPA-based ink
The conundrum
I have a security printing ink that I make by adding an IR-absorbing dye to a 50/50 mix of Isopropyl Alcohol and distilled water. The ink solution is pale green but dries virtually ...
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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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How can I increase the viscosity of dilute hydrochloric acid
I'm cleaning the mortar off a new clinker brick wall. Walls actually. I hate this job. The builder told me to wash down the wall with weak HCl, leave it for a minute or two, and then spray it off with ...
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How to drain engine oil by understanding oil viscocity issues
I asked this on the stackexchange automotive site but didn't get much response perhaps because it entails some chemistry knowledge. I could have asked without mentioning the automotive details however ...
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Are there any fluids which are both viscous and volatile? [closed]
I'm looking for a viscous fluid which will evaporate (completely) rather quickly.
If propylene glycol evaporated like acetone, that would be the dream ticket, but neither the viscosity nor the ...
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Will PAEK polymers hydrolyze in concentrated sulfuric acid?
One of my duties at the company where I work is to perform intrinsic viscosity (IV) experiments on PAEK (poly(aryl ether ketone)) polymers. These polymers don't dissolve well in most solvents, so the ...
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Are viscoelastic materials to be considered solids or fluids?
I recently stumbled upon the concept of viscoelasticity. Not being a chemist, but being interested in the topic, I started to read the wikipedia article.
The main thing I extracted from it is:
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Is it possible to make synthetic oil without fossil fuel? [duplicate]
If human ran out of crude oil and all other fossil fuel, are we still able to create synthetic oil? I've searched online about the raw material of synthetic oil, but I'm still not sure if none of the ...
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Ethanol Water mixture viscosity
It is found that increasing composition of $Ethanol$ in $Ethanol$-$water$ mixture increases the viscosity of the mixture upto certain composition, but after that the viscosity begins to decrease again....
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Near melting thermoplastic material accumulates in the sharper corners. What is this phenomenon?
I have a part made of a thermoplastic material. When I heat it up and cool it down, the dimension of the part changes non-uniformly. Somehow the melted material tries to fill the sharper corners. So ...
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What is viscosity in terms of chemistry?
In physics, viscosity is the force applied in a unit area times time or basically Pascal times second. We could say that it is a measure of its resistance to gradual deformation by shear stress or ...
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What chemical should I use to thin UV cure epoxy?
The epoxy that I am working with is UV curable with a cycloaliphatic epoxy resin base. I am trying to reduce the viscosity. Whatever I add to thin the epoxy, it needs to be able to evaporate off so ...
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Alkali metals and viscosity
I've recently conducted a viscosity experiment to find the relationship between alkali metal ions, the concetration of the solution, and the viscosity of the solution. We used the Oswald viscometer to ...
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Why does viscosity decrease when divalent cations are dissolved into aqueous solutions of sodium carboxymethylcellulose?
Sodium Carboxymethylcellulose (CMC/NaCMC/Aqualon) is a common product used in many instances for its unique properties, especially its ability to make solutions viscous. It is well known that the ...
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Pressure increase due to the reaction of CaO and HNO3
Currently I'm facing difficulties in determining the pressure increase due to the reaction between $\ce{CaO}$ and $\ce{HNO3}$. To be more specific, we first fill a vessel with $\ce{H2O}$ and $\ce{CaO}$...
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Increase in Viscocity in Gases with Temperature
Why does viscocity increase with temperature in gases? When they gain kinetic energy, they should be more free right?
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Why is sugar syrup so sticky?
On the festival of Diwali, Indians exchange sweets and share their love. I did just that this very morning, but things don't always go the right way. I dropped a box of sweets and the sugary syrup ...
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Why isn't viscosity considered a property of solids?
Viscosity is defined as a measure of resistance to flow which arises dues to internal friction between layers of fluid as they slip past one another while liquid flows.
Why can't we say that ...
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