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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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What is 'spray foam' or 'expanding foam'?

At the wikipedia are: Spray foam (expanding foam in the UK) is a chemical product created by two materials, isocyanate and polyol resin, which react when mixed with each other and expand up to 30-60 ...
Imyaf's user avatar
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3 votes
1 answer
149 views

Question about chemical potential of a multicomponent ideal gas

Consider a pure ideal gas, i.e. only having one component. The chemical potential and free energy of this gas are as follows: $$\mu_1=\mu^\circ(T)+RT\ln\left(P\right)$$ $$G_1=n\mu_1$$ Where n is the ...
bloodybutunbowed0's user avatar
1 vote
0 answers
30 views

Estimation methods for temperature evolution of a high $\Delta H_{mix}$ dilution ($\ce{KOH}$ in water)

Question up front: Can temperature evolution in solutions be short-hand-estimated by simple state based calculations - with reasonable expectations of precision? (+/- 10° C) I am trying to calculate ...
Stian's user avatar
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What is the most accurate way to determine the amount of water in a material from XRF and LOD-105 results?

this might seem like a silly question but I want to be sure. I have the results from an external laboratory for the bulk chemical composition (by XRF) and moisture (by Loss on Drying to 105 degrees ...
Hendrix13's user avatar
  • 490
1 vote
0 answers
50 views

History of Azeotrope (azeotropic mixtures)

I'm currently researching the history of azeotropic mixtures for an essay, and I've come across some interesting information. The term "azeotrope" was coined in 1911 by English chemists John ...
Max89's user avatar
  • 19
1 vote
1 answer
59 views

Determination of the composition of the mixture based on acid-base titration

The solution can contain $\ce{HCl}$, $\ce{H3PO4}$ or $\ce{NaH2PO4}$ individually or in all possible combinations. An aliquot of $25.00\,\text{mL}$ of this solution consumes $14.56\,\text{mL}$ of $0....
crvenikupus's user avatar
2 votes
2 answers
264 views

How does steam distillation work to extract a substance from a mixture, below its boiling point?

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 ...
donthababakka's user avatar
-4 votes
2 answers
95 views

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 ...
suse's user avatar
  • 803
2 votes
0 answers
26 views

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 ...
Varstraypl's user avatar
4 votes
1 answer
1k views

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 ...
Harjot Dhillon's user avatar
1 vote
1 answer
371 views

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 ...
randomdude's user avatar
11 votes
2 answers
1k views

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{...
Karsten's user avatar
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2 votes
0 answers
69 views

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 ...
cms's user avatar
  • 121
0 votes
1 answer
52 views

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 ...
Attain's user avatar
  • 11
0 votes
1 answer
38 views

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 ...
C_Swann22's user avatar
  • 133
0 votes
3 answers
464 views

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 ...
Venu Gopal Dash's user avatar
1 vote
1 answer
57 views

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 ...
Agerhell's user avatar
  • 127
1 vote
1 answer
380 views

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 ...
roman m's user avatar
  • 121
-1 votes
1 answer
152 views

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 ...
Guilherme Mendonça's user avatar
-3 votes
2 answers
235 views

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 ...
Ale's user avatar
  • 1
6 votes
3 answers
2k views

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 ...
William Chao's user avatar
-2 votes
1 answer
296 views

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% ...
Kale's user avatar
  • 1
1 vote
1 answer
262 views

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 ...
William Chao's user avatar
1 vote
1 answer
90 views

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 ...
Scratch Cat's user avatar
3 votes
3 answers
423 views

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 $...
Karsten's user avatar
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3 votes
1 answer
1k views

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 ...
Half Infinity's user avatar
2 votes
0 answers
68 views

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}{...
N. Virgo's user avatar
  • 1,661
1 vote
0 answers
66 views

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 ...
C. Taylor's user avatar
1 vote
1 answer
156 views

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 ...
Lobna Abouhussein's user avatar
-1 votes
2 answers
125 views

"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 ...
Hellcyon__'s user avatar
3 votes
1 answer
165 views

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 $PV = nRT$, $$\...
Heat's user avatar
  • 360
3 votes
1 answer
354 views

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 ...
acaduck's user avatar
  • 73
0 votes
0 answers
342 views

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, ...
Weesee Chrissy Keebler's user avatar
5 votes
2 answers
798 views

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 ...
hotmeatballsoup's user avatar
0 votes
0 answers
17 views

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 ...
Don D.'s user avatar
  • 1
1 vote
0 answers
48 views

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 ...
noob anomaly's user avatar
0 votes
1 answer
6k views

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 ...
Oliver Abdul's user avatar
1 vote
0 answers
106 views

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 ...
Will Valentino's user avatar
1 vote
1 answer
135 views

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, ...
Oscar Lanzi's user avatar
  • 58.4k
-1 votes
1 answer
1k views

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 ...
Tessaract's user avatar
  • 101
3 votes
0 answers
110 views

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, ...
Jelle Westra's user avatar
13 votes
2 answers
714 views

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 ...
OJFord's user avatar
  • 241
3 votes
0 answers
319 views

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 ...
Shaka Boom's user avatar
  • 2,322
0 votes
1 answer
841 views

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 ...
NinePlusTenEqualsTwentyOne's user avatar
0 votes
1 answer
553 views

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 ...
revans19's user avatar
  • 129
5 votes
2 answers
3k views

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 ...
max sim's user avatar
  • 59
2 votes
2 answers
1k views

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 ...
JustCurious's user avatar
3 votes
0 answers
49 views

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^{...
Josh E.'s user avatar
  • 133
0 votes
0 answers
30 views

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 ...
Efrat Brayer's user avatar
1 vote
0 answers
389 views

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 ...
Jonses's user avatar
  • 65

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