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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 substances or chemical mixtures become paper-like after drying? [closed]

Natural origin is preferable.I googled but didn't find anything.
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12 views

Is the negative excess volume of ethanol/water the cause of my math error?

I have a binary mixture, say ethanol at $90\%wt$ ethanol, $10\%wt$ water. According to Perry's Chemical Engineers' Handbook 9th Ed., that mixture has a density of $0.81797g/cc$ (at $20^{\circ}C$). ...
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Literature on Miscibility Gap, Pair Correlation Function, Interaction Potentials

I have found textbooks/paper which discuss the pair-correlation function of molecules which are influenced by the Lennard-Jones potential. This gives a direct method for obtaining the various ...
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1answer
25 views

How do I identify how many reactions are occurring when precipitating a mixture?

An example of a question is: After dissolving $x$ grams of a mixture of $\ce{Na2SO4}$ and $\ce{NaCl}$ in water, you add an excess of $\ce{BaCl2}$ solution. You filter off the precipitate which ...
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2answers
55 views

Wetting agent for H2O2 solution

I need to increase the wetting of an $\ce{H2O2}$ solution on ceramic surfaces. Does anyone know of a common chemical I can use for this? The properties it would ideally have are: Increases wetting ...
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2answers
52 views

How to separatetwo liquids with both having the same properties?

I was curious if it was possible to separate such liquids e.g. two vegetable oils that happened to have different ingredients, so it is a different liquid, but the same density etc. Thank you!
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1answer
31 views

Mix quaternary ammonium compounds with washing powder [closed]

So to get rid of bad smells from clothes that have stayed wet for long, I am wondering if I can just add a disinfecting product to my wash in addition to regular washing powder. I have a product ...
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0answers
34 views

Why are Colloids Heterogeneous?

I understand that the definition of a heterogeneous mixture is a mixture in which 2 or more phases are present, i.e. you can see the mixture is not uniform. I know a homogeneous mixture is a mixture ...
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1answer
111 views

Connection between Gibbs Energy of Formation and Gibbs Energy of Mixing

Recently I found the following formula, which I cannot verify to be correct. Since I found this formula in several publications I assume that it is correct but I don't know why. First there is the ...
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1answer
52 views

Is the stoichiometric coefficient equivalent to the mole fraction?

I have a small problem to understand (or distinguish between) two concepts of free mixing enthalpy. In several textbooks, I found the following formula for the molar free mixing enthalpy (binary ...
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2answers
64 views

Is the %V/V composition defined for homogeneous mixtures? [duplicate]

Why do major websites such as NASA and Wikipedia discuss the composition of the earth's atmosphere in terms of percentage by volume instead of percentage by amount of substance? Isn't the percentage ...
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1answer
84 views

What forms the emulsion in chocolate?

Some days ago, before buying a chocolate I read the ingredients and saw that it contains a natural emulsifier. A Google search didn't reveal anything about of what the emulsion formed is, do you have ...
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179 views

How does an alcohol's chain length influence it's miscibility with organic solvents?

Recently someone asked a question about ethanol in fuel. This got me thinking about the miscibility of ethanol in different compounds. I know ethanol and water mix infinitely well due to the ...
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212 views

Freezing of alcohol water mixtures below the triple point pressure of water

What happens when you try to lower the pressure of an alcohol-water mixture below the triple point of water? To give a specific example, the freezing temperature of a 50-50 (by mass) ethanol-water ...
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1answer
37 views

How to evenly mix NaCl and Lactose

Q: You have 10 g NaCl (s) and 90 g Lactose (s) (both easily soluble in water.) You want to achieve a 100 g mixture of these two compounds in solid form where they are completely evenly mixed. (A 1 mg ...
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1answer
46 views

Pressure-Volume Formula Question

I have a chemistry homework problem that states the following: $6.2$ L of $N_2$ at $0.74$ bar is mixed with a $15.2$ L sample of $O_2$ at $0.35$ bar. The gaseous mixture is placed in a container of ...
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0answers
211 views

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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1answer
82 views

Separating sugar from soda

I want to do a lab with my students in which they will try to prove how much sugar is in a can of coke. I know that distillation is the go-to method for separating out the syrupy sugar mix, but does ...
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0answers
271 views

Determining enthalpy of combustion of a mixture

I am designing an experiment to see how the enthalpy of combustion changes when you mix different ratios of substances together (e.g. methanol and ethanol in 1:1 , or 1:2, or 1:3 rations etc). I was ...
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1answer
95 views

Is matter really divided in two categories?

Page 1 of almost every Textbook start with the ordinary divison of matter in 2 categories: Substances and Mixtures. Substances, or Pure Substances sometimes, are defined as a form of matter that ...
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0answers
58 views

Effective atomic number

Is there a database which contains the effective atomic number of some "popular" mixtures/compounds (e.g. BaSO4, PbWO4..)? And a comprehension question: Does it make sense to assign an element one ...
3
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0answers
61 views

Why do certain mixtures foam and others don't? How to predict if a mixture will yield a foam?

I recently acquainted myself with the skill of whipping a mixture of sugar, fresh brewed/ hydrated instant coffee into a pale, fluffy, stiff and stable foam. This, as some might know, is known as Café ...
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1answer
82 views

How do antioxidants work? [closed]

A friend and I are doing a project that involves the process behind manufacturing Jet A-1 and specifically the specifications highlighted in DEF 91-91. I was interested to see the information at the ...
3
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0answers
322 views

Calculating total volume mixing NaCl and water

I'm (as a non chemist) trying to calculate the the volume of a NaCl solution. The problem is that I know the volume of water prior to mixing in NaCl, but I want to know the volume of the solution ...
3
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1answer
39 views

Which is the suitable process for ball milling?

Why do we mainly choose the wet ball milling process in spite of dry ball milling process? Both processes are used to make a homogeneous mixture of different compounds.
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74 views

Why does only a single azeotropic composition exist for a mixture of two given substances?

In the image below, which represents a generic composition vs. temperature plot for a mixture, there is a single intersection point between the vapor and liquid curves. This is due to the fact that ...
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382 views

The molar volume of a binary mixture is given by the following formula, derive an expression for the partial molar volumes in the mixture

The molar volume of a binary mixture has been measured at constant temperature and pressure and has been correlated using the following equation: $$v_M = ax_1 + bx_2 - x_1x_2 [c+d(x_1-x_2)],$$ ...
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1answer
308 views

How to separate paracetamol and caffeine?

How do you separate paracetamol and caffeine using high-school laboratory equipment? I was thinking about using the fact that paracetamol has a lower melting point (169 °C) compared to caffeine (...
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0answers
28 views

How to achieve a uniform mix of heterogeneous compounds?

I have liquid PMMA and a solid powder. I want to disperse the powder particles in the PMMA uniformly into a solid block. So while the PMMA is still in liquid form, I pour in the powder and wait a ...
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1answer
61 views

Derivation of formula used in calculating molecular mass from a mixture

In a solution to a problem, to calculate Molecular mass of unknown gas from a mixture containing $\ce{O2}$ in $80~\%$, the author used the formula : $\frac{1}{\sqrt{M_\text{mix}}}=\frac{X_{\ce{O2}}}...
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0answers
1k views

Isolation of codeine phosphate from Tylenol 2

So here is my question. This may be controversial for some, but I would like to tell you it is purely speculative and has no bearing on anything I would actually do. If one has in their hands a ...
2
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0answers
81 views

Heat capacity of mixtures is higher than their pure contituents?

I'm currently studying the effects of how changing mixed-refrigerant compositions effects their heat capacity. Surprisingly, my data suggests that some combinations of mixed-refrigerants have heat ...
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0answers
6k views

How to calculate the vapour density of a mixture?

I have a gaseous mixture of $\ce{H2}$ and $\ce{CO2}$ which contains $66\%$ by mass of $\ce{CO2}$. I have to figure out the vapour density of the mixture. My approach: let's assume $\pu{100 g}$ of ...
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1answer
215 views

How to calculate the latent heat when there is a boiling temperature range?

I have a DME (dimethyl ether)- methanol - water mixture with the mol fraction composition: DME 0.4295, methanol 0.1353, water 0.4351. This mixture has a boiling temperature range: dew point 141.6 °C ...
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1answer
826 views

Heating a mixture of methanol and water?

I have a mixture methanol and water, at 25°C, and I want to take it to 250°C. I'll use two heat exchangers: one for taking the mixture from a liquid state (25°C) to a vapor state (X°C), and the second ...
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1answer
516 views

Will water allow salts to be dissolved in methanol (that are otherwise poorly soluble)?

If we make a mixture of water, methanol and a salt like $\ce{FeCl2}$, $\ce{NaCl}$ etc, will the ability of water and methanol to mix allow $\ce{FeCl2}$ and $\ce{NaCl}$ to be a part of this mixture and ...
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1answer
921 views

Is it possible for a compound to be soluble in a mixture of solvents but not the individual solvents?

Some weeks ago one of my friend needed to use turpentine. As a good but ignorant chemist on that point I did some research about it. I found (at the beginning) in the French wikipedia page of ...
3
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2answers
211 views

Mixing water and oil in microgravity outside of a container

What would happen if I where to mix water and oil in a vacuum in microgravity where the temperatures were low enough so that the oil and water remain liquids also, the mixture is not inside of a ...
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0answers
288 views

What is the pH of a solution that results of a mixture of two others with known pH?

Solution A has a pH of 1, soultion B has a pH of 6. If I mix the same volume V of each solution into one, what will be the pH of the resulting solution? I'm guessing here as no more information has ...
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3answers
425 views

How does a mixture not retain its chemical identity?

My book says that matter can be classified as an element, compound, or mixture. It further says that a pure substance (or substance) is matter that has distinct properties and a composition that doesn'...
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0answers
74 views

Chemical theory, formula(s) that predict final *volume* of a solution?

I asked this question a couple years back regarding the volume of a mixture being less than the volume of the original solute and solvent, but this question asks if there is theory and/or formulation ...
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1answer
1k views

Will adding apple cider vinegar to freshly pressed fruit juice preserve it

Would adding apple cider vinegar to freshly cold pressed fruit juice be able to preserve the fruit juice and extend its shelf life? Would the juice change into vinegar with time?
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What happens if I increase the amount of water on water based epoxies?

I am using a water based epoxy coating that is composed of a resin and a hardener. There is a specific amount of proportion to use to obtain the optimum cured coating. But I am trying to introduce ...
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1answer
90 views

Is it possible for the remaining solute of a saturated solution to form a single even phase from top to bottom (similar to that of a colloid)?

If a solute that dissolves in a liquid solvent has reached high enough levels to cause saturation within the solution, is it possible for the remaining solute particles to form an evenly distributed ...
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1answer
52 views

Is there a way to find the mixture type with just the molecular formulas and masses of the solute and solvent?

If you had the molecular formula and molar mass of a solvent and a solute and no other specific information about the two, could one deduce the type of mixture (suspension, colloid, solution) they ...
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1answer
430 views

Titration to determine the amount of hydrogen peroxide

I have a mixture of sodium carbonate, sodium bicarbonate, ammonium carbonate, copper (II) sulfate, hydrogen peroxide, and sulfuric acid. I'm titrating potassium permanganate against this mixture to ...
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2answers
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Why is water considered a pure substance instead of a mixture?

Why is water considered a pure substance instead of a mixture? Wouldn't it, when the hydrogen atoms combine with the oxygen atom, be considered a mixture, because the atoms were combined to form a ...
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1answer
353 views

Why does mixing inks make subractive colors?

I have little knowledge of color theory and chemistery. Recently I came to know that printers use CMYK colored inks and combine them in different proportions to achieve any color on print. Let us ...
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1answer
2k views

Boiling point elevation for a mixture of ethanol and water

Properties such as boiling point, freezing point and vapour pressure of a pure solvent change when solute molecules are added to get homogeneous solution. These are called colligative properties....
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1answer
48 views

How to deposit a durable layer of sensing molecules in a PVC matrix on the tip of an optical fiber?

Here is the situation that I have been tacking for weeks and I have still not understood. We are trying to understand how to do this: This mixture for the preparation of the "LI–PVC" was obtained ...