Questions tagged [colligative-properties]

Colligative properties of solutions are properties that depend upon the concentration of solute molecules or ions, but not upon the chemical identity of the solute.

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Which "exotic salt" can lower water's freezing point by 70 °C?

The Medium.com article Mars Phoenix Lander, 10 Years Later shows several remarkable images and discoveries on Mars by the Mars Phoenix Lander circa 2008. One image (shown below) shows what looks like ...
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How much salt (or any other substance one can find in a kitchen) do I need to add to make water boil at 104 °C?

I've seen some formulas around in other questions and Google searches, but my chemistry is pretty much dead so I have no clue where to find the relevant values to calculate it myself. I just need to ...
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The connection of the "R" in the ideal gas law and osmotic pressure [closed]

I am studying chemistry and biology at the same time, and have encountered a problem. In the ideal gas law, the $R$ is the ideal gas constant, and its value is $\pu{0.0821 L atm mol-1 K-1}.$ However, ...
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Detailed kinetic explanation for vapor pressure reduction by dissolved solute?

The following problem was asked in JEE Mains 2020 (Sept 2, Shift 1), An open beaker of water in equilibrium with water vapor is in a sealed container. When a few grams of glucose are added to the ...
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Does Raoult's law hold for immiscible liquids?

I know that Raoult's law holds true only for a non volatile solute in a volatile solvent mixture wherein the vapour pressure of the solution gets lowered due to the addition of solute. Now, first of ...
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How to approximate the pH of a box of water molecules with one proton?

I have a cubic box of length $L = 12.42\ \mathrm{\overset{\circ}A}$, containing $60\ \ce{H2O}$ molecules and $1\ \ce{H+}$ ion. How can I approximate the $\mathrm{pH}$ of the system? Following the ...
762 views

The relationship of the osmotic pressure of a polymeric solution and its the molecular mass

Why is the osmotic pressure of a polymeric solution decreases when the molecular mass is increasing? I am honestly unsure if the above statement is true, at least it seems to me to be true. When I ...
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Relationship between freezing point depression and hydrogen bonds

Freezing point of a solvent is decreased due to the added solute particles in it. e.g. ions. Therefore electrolytes contribute to lowering freezing point (say for physiological conditions). If a ...
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Why do colligative properties depend only on number of solute particles?

Colligative properties depend solely on the number of even though the interactive forces are different for different solute-solvent pairs. So why is the dependence only on the number of solute?
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Does the boiling point of an aqueous solution depend on what the solute is?

Consider a situation where we have two aqueous solutions which have the same concentration (e.g. 1 M), but the solute is different. For example, one is a solution of glucose, and the other is a ...
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What is the derivation for the expression of depression in freezing point?

In my textbook, it is written that the expression for depression in freezing point is $$\Delta T_\mathrm f=K_\mathrm f\cdot m$$ where $\Delta T_\mathrm f$ is the freezing point depression (defined as ...
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Is there any difference between isotonic and isosmotic solution?

Is there any difference between isotonic and isosmotic solution? Can we say isotonic solution do not show osmosis because they have same osmotic pressure?
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Why does the osmotic pressure method offer an advantage over other methods of molar mass calculation? [closed]

Measurement of osmotic pressure provides another method of determining molar masses of solutes. This method is widely used to determine molar masses of proteins, polymers and other macromolecules. The ...
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Why do we use molality on describing colligative property?

I'm satisfied with the explanation about Raoult's law that the chance of vaporizing will depend on the surface exposed to the atmosphere and solute will decrease such chance by taking portion of the ...
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Why is the boiling point of sugarcane juice lower than the boiling point of water?

As the boiling point is a colligative property, one would expect that the boiling point of sugarcane juice should be higher than pure water because Sugarcane juice contains water (75–85%), non-...
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How do repulsive solute interactions affect the van't Hoff factor?

Context. Consider an ideal solution, one in which the intermolecular solvent-solvent, solute-solute, and solute-solvent interactions are all equal. The presence of a solute therefore produces (solely) ...
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Do lyophilic sols have an electrical double layer?

"There are two factors which are responsible for the stability of lyophilic sols. These factors are the charge and solvation of the colloidal particles". Quoted from NCERT book of OC But we ...
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Intuitive explanation for depression of freezing point

Why does depression of freezing point takes place if a non-volatile solute is added to the solution? For more details about the question checkout this link below Depression of freezing point
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Order of molecular mass of solvent; given boiling point [closed]

Given three solvents X, Y, Z. Order of boiling point of pure solvent X < Y < Z and same order of molal elevation constant ($K_\mathrm{b}$). Find the order of molecular mass. So I got this ...
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Relative lowering of vapour pressure

Why is lowering of vapour pressure (Po - Ps) temperature dependent? And why is relative lowering of vapour pressure (1 - Ps/Po) independant of temperature?
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Depression of freezing point [closed]

Recently, I learnt that by adding a non-volatile solute to a solvent, the vapour pressure of the solution is decreased and consequently its boiling point. Facts and definitions freezing point: "The ...
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How to calculate the depression in freezing point of a solution in which there are multiple solutes being added?

In just about every problem I've encountered earlier, all such questions describe the process for calculating the depression in freezing point for a solution wherein there is only one solute. However, ...
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Eutectic plot - freezing point lowering

I have a doubt about the correlation between eutectic plots and freezing point lowering. The freezing point lowering, as well as all colligative properties, is defined in the presence of a volatile ...
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Colligative properties: why does the size of solute not matter?

Colligative properties are defined as the "properties of solutions that depend on the ratio of the number of solute particles to the number of solvent molecules in a solution, and not on the ...
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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 ...
1 vote
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Do colligative properties depend on the number of solute molecules?

Colligative properties are properties that are affected by the number of solute molecules dissolved in the solution. True or false? I think the statement is false, and the correct one should use "...
1 vote
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Boiling point elevation with multiple solutes

I've encountered a problem where glucose and $\ce{NaCl}$ are mixed with water and $\Delta T$ is to be calculated. I've calculated $\Delta T$ for both glucose ($i = 1$) and $\ce{NaCl}$ ($i = 2$) ...
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Freezing Point Depression and Temperature Decrease

I don't have a problem understanding the chemical mechanisms underlying freezing point depression or colligative properties in general, but what I cannot seem to grasp is how if you add salt to ice ...
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How to calculate the freezing point of an equimolar ethanol: water mixture using colligative properties [closed]

I am familiar with how to calculate the freezing point of a mixture with a 9:1 molar ratio of ethanol to water (see below). I can understand that ethanol, having a higher mole fraction, is considered ...
1 vote
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Understanding the Osmotic Pressure formula

$$\Pi = iMRT$$ Can this be rewritten as $\Pi = ORT$ where $O =$ osmolarity? The only reason I ask is because my book doesn’t talk about the relationship between osmolarity and molarity, but I came ...
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Are colligative properties applicable for volatile liquids and gases in liquid solvent? Why/Why not?

My teacher told me that the expressions for calculation of colligative properties like lowering in freezing point are only applicable if the solute is non volatile liquid or a solid. We cannot apply ...
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Elevation in boiling point of water [closed]

$\pu{1060 g}$ of urea aqueous solution is subjected to heating. It starts boiling at $\pu{100.53 °C}.$ It is heated up to $\pu{102.12 °C}.$ Find amount of water vapourised in grams. (Pure water ...
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Is vapour pressure truly a colligative property?

Colligative properties are generally defined as A colligative property depends only on the ratio of the number of particles of solute and solvent in the solution, not the identity of the solute. ...
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Proper explanation for depression of freezing point [closed]

Why does depression of freezing point takes place if a non-volatile solute is added to the solution? Depression of freezing point
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Freezing of a beverage

I am trying to generally describe the process of freezing beer and how the different ingredients influence the freezing process. My general approach right now is to observe a beer as 90% water and 10% ...
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Determining the molar mass of a substance by the osmotic pressure as a function of a mass concentration

Let's say that I have a solution of some substance in some solvent. The density of the solute is $\rho_\text{solute}$ and the density of the solvent is $\rho_\text{solvent}$. Suppose that the osmotic ...
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How to determine the van't Hoff factor for different salts in water experimentally?

How do I experimentally determine the van't Hoff factor for different salts in water? I'm going to dissolve each of sodium chloride, potassium chloride, and lithium chloride in $\pu{20 mL}$ of water ...
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Finding the reduced pressure to distill a solution containing 0.4 g of naphthalene in 25 g of chloroform at 50 °C

Chloroform boils at $\pu{62 ^\circ C}$. For a solution containing $\pu{0.4 g}$ of naphthalene in $\pu{25 g}$ of chloroform, the boiling point is elevated by $\pu{0.45 K}$, to avoid any decomposition ...
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How to find relative lowering of vapour pressure from phase diagrams in terms of temperature?

Problem Answer My question Does a tie rule exist for solution solvent phase diagram to express relative lowering of vapour pressure in terms of temperature? The phase diagram is the one ...
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Freezing point lowering for a mixture of many liquids

I have been taught that if I have a solute of molality $m$ mixed with a liquid, the freezing point in lowered by an amount $K_\mathrm{f}\cdot m$ where $K_\mathrm{f}$ is the molal freezing depression ...
1 vote
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Does the mole fraction of a solution change with Vant Hoff factor?

I reason that as mole fraction is a measure of colligative properties, increase in the Vant Hoff factor ( and hence increase in the value of colligative properties) should also leave a mark on the ...
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How does dry air get saturated in the Ostwald-Walker Method?

This question was already asked and this was the answer that was posted: "So basically, before you start the experiment the vapors have already formed, meaning that thermodynamic equilibrium has been ...
1 vote
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Is my proof valid for the formula of elevation in boiling point? [closed]

Is my proof valid for the formula of elevation in boiling point? proof By Clausius clayperon equation, $$\ln(P)=-\frac{∆H_v}{RT}+c$$ Differentiating, \frac{dP}{...
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What happens to the gas inside cold drinks as the cold drink is frozen?

According to Henry's law the amount of gas dissolved is directly proportional to the pressure exerted by a gas on the surface of the liquid. And we know if we increase the temperature, the amount of ...
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Colligative properties of colloids [closed]

The following lines are from my textbook: Colloidal particles being bigger aggregates, the number of particles in a colloidal solution is smaller than a true solution. Hence, the values of ...
336 views

Deviations from Raoult's Law [closed]

A solution of two compounds may be an ideal solution and follow Raoult's Law, or it may show a positive or negative deviation from Raoult's Law. How to predict that whether a solution of two given ...
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Why is water transferred from a beaker of pure water to a beaker of sugar solution when placed in the a closed container?

I know that there is something to do with the vapour pressure of pure water being higher than the vapour pressure of the sugar solution, but I still can’t really explain what happens on a molecular ...
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