Questions tagged [mixtures]
Questions related to the physical combination of two or more substances on which the identities are retained and are mixed in the form of solutions, suspensions, and colloids.
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How does steam distillation work to extract a substance from a mixture, below its boiling point? [duplicate]
This is a small confusion I have regarding steam distillation. Let us consider a sample of water mixed with an organic compound that is insoluble in water. Let us also consider that the boiling point ...
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Does emulsify mean to combine or break down?
In chemistry, emulsification is defined as the "an additive which helps two liquids mix" (Source: Wikipedia), "a mixture of two or more liquids that are normally immiscible owing to ...
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Creation of a Solution of Liquid Latex + Sodium Caseinate with Polyvinyl Alcohol
I am going to be experimenting with creating different types of liquid latex formulations, primarily for the purposes of increasing shear strength and tear resistance, as well as just general ...
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Why is glass a mixture and not a solution?
While studying mixtures and solutions, I read that glass is a mixture and not a solution.
Then I searched over the Internet about it, but I got the same answer that it is a homogenous mixture.
But ...
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Mixture of two ideal gases
Why is $\Delta H_{\mathrm{mix}}=0$ in a mixture of ideal gases? If $\Delta H=\Delta U + \Delta PV $ and I know that in ideal gases there are no interactions between molecules so $\Delta Q=0$ and I ...
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Why would there be a non-zero Gibbs energy of mixing for ideal gases?
When two ideal gases $\ce{A}$ and $\ce{B}$ mix, they don't interact. The chemical potential of each gas is independent of the other, e.g. for $\ce{A}$:
$$\mu_\ce{A} = \mu_\ce{A}^\circ + R T \ln \frac{...
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How does the Szilard-Einstein refrigerator design evaporate its refrigerant?
In their 1927 patent, Leo Szilard and Albert Einstein use butane as a refrigerant in their non-compressive refrigerator design. In the patent the authors begin the description of the principle of ...
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Any way to predict what quantities of heptane and chloroform will match the density of water?
I am trying to make a solution of heptane and chloroform that matches the density of water.
Is this something which must be done experimentally as it is generally unpredictable? Does a software exist ...
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Dependence of the permittivity on solvent mixing ratio
I am doing DFT calculations on an organometalloid compound to assess whether it dissociates into an ion pair in different solvents. I suppose that the more polar the solvent is the more stable this ...
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Is milkshake a heterogeneous mixture?
In my textbook, one of the examples of a heterogeneous mixture is milkshake, I don't see how ?
I think the answer depends on the fact that How many phases are there in a milkshake, which I think ...
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More minerals in seawater at greater depths?
There are lists such as the one below detailing how much of different minerals seawater contains:
https://web.stanford.edu/group/Urchin/mineral.html
(For instance )
Would you expect this to be the ...
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Why water volume went up by almost the same amount after adding salt?
Seems like it's a well-known fact that adding salt to water will not raise the water volume by much (e.g.: Why there is no change in water level when salt is added? )
I've done this experiment at home ...
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Does the equilibrium constant of an ideal liquid mixture reaction depend on pressure?
I want to calculate the equilibrium constant K[T] for a the following reaction:
$$\ce{CH3OH(l) + C4H8(l) -> C5H12O(l)}$$
It is assumed that the mixture is ideal and the reaction takes place at 14 ...
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Calculate the concentration of HF in aqueous solution of NH4F and NH4HF2 mixture
There is a similar question on this site, but here i have a mixture.
I have a mixture of NH4F (35% weight) and NH4HF2 (8% weight) in water. How do I calculate the weight % expressed in HF? or the ...
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Does stoichiometric gas mixture produce the highest explosion pressure (or energy) compared with other explosive limit mixture?
I understand that a stoichiometric mixture contains a balanced mixture of air and fuel and both fuel and air are completed consumed. For example, the ideal stoichiometric mixture for propane is ...
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What's the stoichiometric ratio of Kerosene to a mixture of 50% water and 50% hydrogen peroxide [closed]
So I'm wanting to do some testing with combustion of certain liquids, and I'd like to know what the right ratio is for these liquids. What I'm going to be using is regular kerosene (NOT RP-1) and 50% ...
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What is the composition of air (oxygen and nitrogen) as it is displaced by propane?
We have purchased an oxygen analyzer that is calibrated with pure nitrogen and pure oxygen. It measures 20.91% when it samples air in the atmosphere. The analyzer is reading in %volume.
We have built ...
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How do clay particles form a colloidal mixture?
I have been learning about water coagulation in my chemistry textbook. Apparently, before being treated, water has clay particles, primarily silicates and aluminosilicates, which apparently have a ...
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How is the entropy of mixing related to chemical reactions in solution?
When calculating the Gibbs energy of reaction for reaction mixtures at arbitrary concentrations, you use the following expression:
$$\Delta_\mathrm r G = \Delta_\mathrm r G^\circ + RT\ln Q$$
The term $...
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Is the entropy change positive or negative in this reaction?
Suppose I have a reversible reaction
\begin{align}
\ce{A(g) + B(g) <=> C(g)}\\
\end{align}
with equilibrium constant K.
Its ΔΗ is positive throughout.
Now, suppose I start with 1 mole ...
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Chemical potential vs derivative of free energy
Let $x$ be the concentrations of species in a chemical system, and let $G(x)$ be the Gibbs free energy. My understanding is that the chemical potentials should be given by
$$
\mu_k = \frac{\partial G}{...
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What is the necessary and sufficient condition for a mixture to be ideal?
I am trying to understand some concepts from solution thermodynamics related to ideal mixtures and fugacity. My main question is what is the necessary and sufficient condition for a mixture to be an ...
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How to achieve desired response of a non Newtonian fluid prepared from silica nanoparticles and polyethylene glycol (PEG 400)?
I am working on non-newtonian fluid project. I have experimented with cornstarch and water and achieved the consistency desired with 55% cornstarch and 45% water.
Now I want to create similar outcome ...
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"No heat, light or electrical energy may be evolved or absorbed during the formation of a mixture." What about heat from friction?
I was reading about mixtures in my chemistry textbook. One of the characteristics of mixtures that was stated was "No heat, light or electrical energy may be evolved or absorbed during the ...
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Why does the equation for chemical potential apply to liquids and aqueous solutes?
The equation for chemical potential of a gas can be derived as such:
At constant temperature,
$$\mathrm dG = V\,\mathrm dP \label{eqn:1}\tag{1}$$
Substituting with the ideal gas law $PV = nRT$,
$$\...
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derivation of activity coefficient from Margules laws?
basics
In Margules activity model, the excess Gibbs free energy is expressed as:
$$
\frac{G^{ex}}{RT}=X_1 X_2 (A_{21} X_1 +A_{12} X_2) + X_1^2 X_2^2 (B_{21}X_1+ B_{12} X_2) + ...
$$
meanwhile, we ...
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How do I keep my homemade liquid fabric softener from separating?
I have a recipe for a homemade liquid fabric softener that smells good and works great, but I have to shake it every time before I use it. It gets old fast.
The recipe calls for:
12 cups hot water, ...
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Name of particles in a suspension
What is the proper name given to the particles in a suspension? Suspensae perhaps? When these particles are brought out of suspension, and precipitate down to the bottom of the mixture, what is that ...
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DI water vs. Tap water in ethanol-water and salt phase change reaction
We did a very simple lab like one you would do in highschool showing that you can seperate the phases of water and ethanol using salt. As simple as it sounds, we could not get it to work no matter ...
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Why is my ethanol–water mixture showing negative change in enthalpy of mixing? [duplicate]
I am conducting an experiment where I mix two solutions $\text{A}$ and $\text{B}$ and then I am measuring the temperature change (for real solutions, i.e., $\Delta_\mathrm{mix}H\neq 0).$ I took the ...
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Is the density of a mixture ever just the sum of the densities of each species in the mixture? [closed]
My current hypothesis is that this is true when the volume is finite and perhaps this would cause the densities to be additive.
For example, imagine there is a closed container, 2 L in size. And ...
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Methods of mix thick liquids (3D printer Resin), stir, shake or acoustic?
Most of the 3D printing community mixes resins by hand by simply shaking them.
This is not 100% effective (I believe) and also creates a lot of bubbles that get in the prints.
What method would you ...
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Mission: Impossible? Hydrocarbons in an aqueous liquid (e.g. humulene in beer)
Your mission, should you decide to accept it, is to describe how hydrocarbons can be stably mixed into a water-based liquid such as beer, as in this question. According to the usual textbook wisdom, ...
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How to thermally insulate beaker glass on hotplate?
I bought a magnetic stirrer with a hot plate almost identical to this one.
I am trying an experiment where I need to heat the beaker/mixture to about 100 degrees C. However the mixture/beaker is ...
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Gibbs free energy of mixing in a control volume
I'm trying to model the amount of energy lost due to mixing of a $\mathrm{HCl}$ solution using the Gibbs free energy of mixing. However, I really like a second opinion on the model and the results, ...
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Do azeotropic mixtures evaporate proportionally?
Do azeotropes evaporate, without boiling, in proportionate amounts, or does this property describe their behaviour only at boiling point?
Concretely, if 91% isopropyl alcohol/water (by volume, i.e. an ...
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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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How many boiling points does a mixture of liquids have?
Let's say I have a mixture of two miscible liquids. I want to get the liquids by fractional/pure distillation. My textbook says a mixture boils over a range of temperatures. On the contrary, another ...
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Methanol-water mix freezing points - clarify contradictory online data > 60% w/w?
Extending an exploration of windshield washer-fluid choices to freezing points of methanol-water mixes, all web-sources located agreed to within a couple of degrees from 0-60% w/w, yet above this ...
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A solution is cloudy at lower concentration and becomes clear at higher concentration. Why?
This might be just an "everyday life science" question. I am a university professor but not in Chemistry so please educate me. Today I was adding some floor cleaner formula to water as ...
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Azeotropic mixtures and Raoult's Law
So I find this everywhere:
"Mixtures showing large deviations from Rault's law form azetropic mixtures at specific compositions"
My questions are:
(a)Why is it so?Why deviation from Raoult's ...
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Molecular diffusivity of a three-component mixture
I usually used a following expression by Fuller & Schettler & Giddings to predict molecular diffusivities of binary mixtures:
\begin{equation}
D_i = \dfrac{1\cdot 10^{-4}\left(0.00143\cdot T^{...
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Total concentration conversion
when dealing with waste water and the total values of P, N, C are given in ppm units, what molecular weight is used for converting from ppm to molar?
for Example- what will be 12 ppm of P(T) in Molar ...
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What is the explanation of negative temperature coefficient in ignition delay of a fuel?
When studying the ignition delay of a fuel, some fuel have a negative temperature coefficient area (NTC) where an increase of initial temperature of the mixture air/fuel produces an increase of the ...
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Saponification - Oil and Alcohol?
I've been reading that a saponification reaction typically involves NaOH or KOH. I was wondering - could anything that contains an OH group cause a saponification reaction? For instance, coconut oil + ...
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DIY lipid nanoparticles
I, and a number of friends, take a bunch of supplements that are polyphenols and often flavin-oids, -ols or -es; also numerous carotenoids. Examples include quercetin, luteolin, fisetin, curcumin, ...
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What happens if you superheat timber in a zero oxygen environment? [duplicate]
I was thinking to myself, what would happen if you were to put a lump of wood in a zero oxygen environment and superheat it? It couldn’t burn because fire needs fuel, heat and oxygen however because ...
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Are the particles of a colloid "solid"?
I want to understand what are the particles of a colloid in the microscopic scale. According to Wikipedia:
A colloid is a phase separated mixture in which one substance of
microscopically dispersed ...
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Find gas pressures of injection knowing mixture pressure without knowing volume
Let's say we have a gas 1 moving inside a pipe (we don't know the geometry) at mass flow rate $Q_1$ and temperature $T_1.$ We inject a gas 2 at some point inside the pipe with gas 1 at mass flow rate $...
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Find the molality
Find the molality of a mixture formed by mixing $200cm^3$ of $HNO_3$ that has a $69\%$ of richness and density $1.41g/mL$, with $1L$ of the same acid with $1.2M$ and density $1.06g/mL$.
Attempt. The ...
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