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Questions tagged [osmosis]

the spontaneous net movement of solvent molecules through a semi-permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides.

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Dependence of Osmotic Effects on Particle Size

van't Hof's equation for osmotic pressure is derived with the assumption, among others, that the particle size of the solute is comparable to the particles size of the solvent. It holds well so long ...
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Will a reverse osmosis membrane exclude perfluorobutanoic acid?

I recently did a water quality test and it showed a detectable level of perfluorobutanoic acid, a potentially dangerous carboxylate PFC. Will a reverse osmosis water purification system exclude this ...
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Mechanism of Water Potential

The idea of water potential still confuses me. I understand the general idea: water moves from an area of higher water potential to an area of lower water potential. However, I still do not understand ...
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Why does water diffuse from a lower solute concentration to a higher one?

I'm studying biology and this came up in the context of passive transport. I understand why, in general a gas moves down a concentration gradient (the random movement of gas particles and probability)....
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239 views

Molar mass of a protein from osmotic pressure

The height of a column of liquid that can be supported by a given pressure is inversely proportional to its density. An aqueous solution of $0.010 g$ of a protein in $10 mL$ of water at $20^oC$ ...
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195 views

What does the osmotic pressure do in an electrolytic solution?

I have learnt that in an electrochemical cell, the osmotic pressure in the solution hinders the flow of ions from the electrode to the solution, rather some ions may accumulate on the electrode ...
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Why does sugar water diffuse better than water through a gummy bear?

Our science class did a lab about osmosis, where we left a gummy bear in solutions of salt and sugar, as well as tap water. When we came back, we were all surprised to see that our gummy bears in ...
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Is Reverse Osmosis Sanitizer safe to use? [closed]

The Sanitizer is called Sani-System (For Reverse Osmosis). The purpose is to get rid of the bacteria within a Reverse Osmosis system (Priority is the tank: that holds the water) -- edit Safe meaning ...
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245 views

Is osmosis due to osmotic pressure?

Okay, I am getting real confused on how water flows from a hypotonic solution to a hypertonic solution through a semipermeable membrane. It is known that hypertonic solutions have higher osmotic ...
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318 views

Why does solvent particles move towards solution when semi permeable membrane is added?

When a SPM is added in between solute and solution the water molecules move towards salt water even though the concentration is same both sides. Why does this happen? According to SPM's perspective, ...
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Inverse use of a reverse osmosis membrane

I've got a question regarding Osmosis. I recently came across 'Thin-film composite membranes'. Those are build up of layers with one of those being semipermeable. As I'm not well versed in chemistry, ...
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Is that correct to say that osmosis happens with water only?

Is that correct to say that osmosis happens with water only (based on the definition below) or it can happen with other liquids as well? I've read the following definition in a book called "BRS - ...
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Two different containers full up with pure water and salt water in osmosis. What happens?

I would like to understand what happens when there are two containers which are connected together and separated by only semipermeable membrane. Then in one container I fill up (all the way to the top)...
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What solute should I use with dialysis tubing if I want a 100% retention rate?

I purchased dialysis tubing from the Carolina company. The molecular cut off is 12,000-14,000 Daltons and I've been using table sugar for my experiments with it to raise columns of water. While the ...
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How does osmosis work?

I have (very) basic knowledge in chemistry. I am curious as to why osmosis works. I read a couple of introductory chemistry books and also searched online but most explanations I found only explained ...
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Would osmosis occur between two solutions of equal moles of water but unequal moles of a nonpolar molecule?

Earlier I learned that osmosis was, like diffusion, a result of the laws of entropy, kinetic energy, and random movement. However, if you have two solutions of equal moles of water, then net movement ...
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Can H4O 2+ form?

Like $\ce{NH4+}$ ,Is there any possibility of formation of $\ce{H4O^{2+}}$ (of tetrahedral structure)? My theory is: it can be formed by osmosis setup where heavy acids like $\ce{H3PO4}$ or $\ce{...
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Why wouldn't solvents be interchanged in isotonic solutions?

While studying osmosis, my book remarks that Two solutions having same osmotic pressure at a given temperature are called isotonic solutions. When such solutions are separated by semipermeable ...
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655 views

What happens when a semipermeable membrane allows only one solute to pass through?

I'm essentially a medical student where we deal a lot with osmosis. But when we are taught, it is done generally with only a single solute in consideration. What if two different solutes are used on ...
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How will water move across a membrane that is permeable to only one solute?

If there are two solutions separated by a membrane, which is permeable only to one solute and the solvent, will there be any net movement? Let's assume the two solutes are glucose and sodium ions, ...
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3k views

How to figure out which substance has the highest osmotic pressure? [closed]

In preparing for an exam and I'm trying to solve the following question. I'm clueless. What should I do? Which of the following water solutions has the highest osmotic pressure? \begin{align} \...
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3k views

Does glycerin promote bacterial growth the same as water?

A sodium chloride + water solution draws the water out from bacteria through the process of osmosis. Would a sodium chloride + glycerin solution have the same antibacterial effect? If I understand ...
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How can semi-permeable membrane be so smart?

According to the definition, a semi-permeable membrane is a membrane that allows only solvent molecules to pass through it; solute molecules are blocked. Solvent molecules flow from the membrane side ...
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Does Reverse Osmosis remove elemental ions from water?

From what I understand, RO is able to remove (or at least considerably reduce) the salts dissolved in water. But thinking about it just doesn't make sense. RO works by filtering the solution using a ...
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1answer
765 views

Osmotic Pressure

If the osmotic pressure of a 0.010 M aqueous solution of sucrose at 27˚C is 0.25 atmosphere, then the osmotic pressure of a 0.010 M aqueous solution of NaCl at 27˚C is (a) 0.062 atm (b) 0.12 atm (c)...
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Can I equalise osmotic pressure using two different solutes?

I understand that there is a pressure gradient between an aqueous solution, e.g. salty water, and, say, pure water due to osmosis. My question is, is it possible to match or almost match, the osmotic ...
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Fundamental physical forces behind osmosis

I wonder which fundamental forces act behind osmosis process? Sum of these forces oppose gravity force, like in this figure: So I wonder what are these forces?
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3k views

Highest osmotic pressure

I’d like to ask a question and clear my misunderstanding. Which of the following 0.01 M solutions have the highest osmotic pressure? -$\ce{NaCl}$ -$\ce{C12H22O11}$ -$\ce{BaCl2}$ -$\ce{CO(...
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Water softener and RO filter

I have a water softener for showers and dishwasher and a reverse osmosis filter for drinking water. For convenience of the install, the RO filter is using softened water (some calcium carbonate has ...
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1answer
845 views

Why is pickle salty? How does salt get into pickle?

I know this may look like some question easily answered with common sense, but please read. If water is the solvent wouldn't the only thing that moves be water? (Osmosis) Edit: this is basically ...
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283 views

Osmolarity and osmotic pressure

You have discovered a new strain of bacteria called Tankeromyces subtilis that has a special outer membrane that is capable of withstanding high levels of osmotic pressure. These bacteria can survive ...
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1answer
3k views

How to calculate the osmotic pressure of a sucrose solution?

The boiling point of an aqueous solution containing sucrose, $\ce{C12H22O11}$, is $101.45~^\circ\mathrm{C}$. Calculate the osmotic pressure of this solution at $35~^\circ\mathrm{C}$, at which the ...
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Converting mm Hg to mm H2O

So here's my problem: What is the osmotic pressure, noted in mm of $\ce{H2O}$, of a solution with 125 micrograms of vitamin B12 ($\ce{C63H88CoN14O14P}$) in 2.50 mL of $\ce{H2O}$ at 25 degrees Celsius....
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How to create a simple do-it-yourself procedure to measure diffusion?

While I am not asking the question here, a recent question concerning osmosis at the Bio SE caught my interest. In a nutshell that question was, given isotonic solutions of sugar inside and outside an ...
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Why is dialysis tubing impermeable to sucrose?

This question was posed a couple years ago but not answered adequately. You can view the older thread here. The cellulose membrane commonly used in high school and university labs is widely available ...
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Use of osmosis to measure molecular weight of macromolecules

How can osmosis be used to measure molecular weight of macromolecules ? Is it applied practically ?
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3k views

What is the colloidal osmotic pressure?

The oncotic pressure or colloidal osmotic pressure is the osmotic pressure developed due to the presence of colloids in a solution. But since the colloids are not true solution, why should the ...
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2answers
441 views

How might one reduce the concentration of bubbles in their ice, from ice cube trays?

So I have been freezing ice a lot recently, and I will come out and say it, as it turns out it is, albeit unlikely, it is sometimes possible for ice to "explode." I was not so aware of this before, ...
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Why is dialysis tubing impermeable to sucrose when it should retain >12,000 Da?

While writing up a lab for biology, I realized that the dialysis tubing for sale online seemed to retain large molecules (12-14,000 Da) but didn't specify an upper bound. I learned that the tubing is ...