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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24 views

How does hydraulic equilibrium work on the particulate level?

I recently learned that osmosis occurs when there is a semipermeable membrane between pure water and a solution of water. The pure water then fills up the solution's side until, as my textbook put it, ...
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real meaning of osmotic and turgor pressures

I am a high school student and I am very confused in how we define osmotic pressure? Osmotic pressure is defined as the pressure required to stop the diffusion of solvent into a solution by applying ...
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What is the difference in mosM and mOsm units, if there is any at all?

I'm reading Agre's paper on aquaporins [1] and he uses a unit called "mosM" throughout the paper, for example: … ocytes were transferred from 200 mosM to 70 mosM modified Barth's buffer. I ...
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Why does osmolarity take into account both penetrating and non-penetrating solutes?

According to Wikipedia: … osmolarity takes into account the total concentration of penetrating solutes and non-penetrating solutes, whereas tonicity takes into account the total concentration of non-...
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Why is RO water more corrosive?

According to several articles from the American Water Works Association, permeate from RO should be stabilized in terms of pH and hardness to avoid corrosion of the distribution piping. How does ...
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Questions Regarding Osmosis

From Costanzo's Physiology: Osmosis of water is not diffusion of water: Osmosis occurs because of a pressure difference, whereas diffusion occurs because of a concentration (or activity) difference ...
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How is equilibrium achieved in osmosis?

According to BRS Physiology book: excessive NaCl intake will lead to an increase in the osmolarity of the Extracellular Fluid (ECF) compartment, and thus will lead to water shift from the ...
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Is reverse osmosis a fancy term for filtration?

In Reverse Osmosis (RO) systems, the water to be purified is pushed against a semipermeable membrane and comes cleaner the other side, the path of water is the reverse of regular osmosis, hence the ...
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Is the salt of a weak acid and a weak base also a weak electrolyte?

I'm able to find a lot of information on acids and bases, as well as strong-strong, weak-strong, and strong-weak salts. However all the introductory materials on electrolytes just stop there and say "...
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Using osmotic pressure to find the molar mass of a compound

Working on-board a research vessel somewhere at sea, you have (carefully) isolated 12.5 micrograms $(\pu{12.5E-6 g})$ of what you hope is pure saxitoxin (a non-electrolyte) from a poisonous (and quite ...
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membrane for a reverse osmosis desalination experiment

We are second year cram schoolers , we are currently working on a project tackling water desalination by reverse osmosis and are required to do an experience. During the process, we encountered some ...
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Is the solution isotonic, hypertonic, or hypotonic?

The problem is shown below. I don't understand how can the tonicity of a solution be determined if the solution has multiple solutes dissolved in it. Do I take the total sum of the mass of solutes ...
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How to find osmolarity of a solution contatining salt and glucose?

What is the osmolarity of a solution that contains $4.00\%$ (m/v) $\ce{NaCl}$ $(M = \pu{58.44 g mol-1})$ and $3.00\%$ (m/v) glucose $(M = \pu{180.18 g mol-1})?$ I know you have to convert percentages ...
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Breast milk with reverse osmosis [closed]

I would like to make life lasting breast milk jewelry. I would need at least 5ml to make it. I've been doing a lot of research to get the best results, so far this questions are the result of more ...
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What are the factors affecting osmosis (bio)? [closed]

Asking from the blood barrier angle. The wikipedia states that glucose, urea, and $\ce{Na/K}$ count. Can there be any other factors, like $\mathrm{pH}$, temperature, hydraulic pressure on the cell ...
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Is osmosis really a special case of diffusion across a semipermeable membrane?

A general idea we have about osmosis is that it is the movement of solvent particles through a semi permeable membrane from a region of high concentration to a region of low concentration. This seems ...
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Is it appropriate to approximate solute particles in a dilute solution as an ideal gas?

I was studying osmosis and I came across the formula for osmotic pressure. I decided to see the derivation for osmotic pressure in a dilute solution. The derivation involved an equation involving the ...
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Is Gibbs energy change during osmosis positive? If so then why is it spontaneous?

For ideal solution, μA=μA* +RT lnxA ln function is an increasing function, means that the higher the xA the higher the μA......(1) Now consider osmosis. From Atkins' Physical Chemistry Ninth ...
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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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578 views

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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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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819 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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463 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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834 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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Reverse osmosis membrane used as an osmosis membrane

I recently came across the so-called 'thin-film composite membranes'. They are build up of layers with one of them being semipermeable. As I'm not well versed in chemistry, I'm unsure, if these ...
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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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239 views

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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789 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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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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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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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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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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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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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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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 ...