# Osmotic Pressure and Equilibrium constant

• WK95
In summary: You already have the values for p_i, R, and T. Just plug and chug.In summary, the osmotic pressure of a solution containing 0.84 g/L of an organic detergent at 25°C is 54.4 torr. To find the molar mass of the detergent, we can use the ideal gas law, where the osmotic pressure equals the product of the molar mass, density, and gas constant divided by temperature. Therefore, we can solve for the molar mass by rearranging the equation and plugging in the given values.For the second part, the equilibrium constant expression for the given reaction is [Pt2+]eq*[Cl-]^4eq/[PtCl42
WK95

## Homework Statement

An aqueous solution contains 0.84 g/L of an organic detergent. The osmotic pressure of this solution is 54.4 torr, at 25°C. What is the molar mass (in g/mol) of this detergent?

## Homework Equations

##pi=MRT##
##R=0.08206L*atm/(mol*K)##

## The Attempt at a Solution

##pi=MRT##
##M=pi/(RT)##
##M=(54.4 torr * 1 atm/760 torr)/(0.08206L*atm/(mol*K))(298.15 K)##
This is wrong but I;m not sure why and how to get the right asnwer.

## Homework Statement

What is the equilibrium constant expression for the following reaction:

PtCl42−(aq)↔Pt2+(aq) + 4Cl−(aq)

Choose from the list below and enter the letters alphabetical order. (e.g. For an equilibrium constant of [Cl-]4eq[Pt2+]eq enter AH.)

A) [Pt2+]eq E) [Cl-]-1eq I) [PtCl42-]4eq
B) [Cl-]eq F) [PtCl42-]-1eq J) [Pt2+]-4eq
C) [PtCl42-]eq G) [Pt2+]4eq K) [Cl-]-4eq
D) [Pt2+]-1eq H) [Cl-]4eq L) [PtCl42-]-4eq

WK95 said:

## Homework Statement

An aqueous solution contains 0.84 g/L of an organic detergent. The osmotic pressure of this solution is 54.4 torr, at 25°C. What is the molar mass (in g/mol) of this detergent?

## Homework Equations

##pi=MRT##
##R=0.08206L*atm/(mol*K)##

## The Attempt at a Solution

##pi=MRT##
##M=pi/(RT)##
##M=(54.4 torr * 1 atm/760 torr)/(0.08206L*atm/(mol*K))(298.15 K)##
This is wrong but I;m not sure why and how to get the right asnwer.

## Homework Statement

What is the equilibrium constant expression for the following reaction:

PtCl42−(aq)↔Pt2+(aq) + 4Cl−(aq)

Choose from the list below and enter the letters alphabetical order. (e.g. For an equilibrium constant of [Cl-]4eq[Pt2+]eq enter AH.)

A) [Pt2+]eq E) [Cl-]-1eq I) [PtCl42-]4eq
B) [Cl-]eq F) [PtCl42-]-1eq J) [Pt2+]-4eq
C) [PtCl42-]eq G) [Pt2+]4eq K) [Cl-]-4eq
D) [Pt2+]-1eq H) [Cl-]4eq L) [PtCl42-]-4eq

## The Attempt at a Solution

It's quite difficult to follow what you have done here.

For the first part, please define the variables used.

For the second part, use the subscript and superscript tags or LaTeX to format your working.

The osmotic pressure satisfies the same equation as the ideal gas law. In your problem solution, you need to use the density of the detergent.

$$ρ=\frac{p_iM}{RT}$$

You need to solve for M.

## 1. What is osmotic pressure?

Osmotic pressure is the pressure required to prevent the flow of water across a semi-permeable membrane due to differences in solute concentration on either side of the membrane. It is a measure of the tendency of a solution to take in more solvent in order to equalize the concentration of solutes on both sides of the membrane.

## 2. How is osmotic pressure related to equilibrium constant?

Osmotic pressure and equilibrium constant are related through the Van 't Hoff equation. This equation states that the osmotic pressure of a solution is directly proportional to the concentration of solute particles and the temperature, and inversely proportional to the volume of the solution and the gas constant. The equilibrium constant is also dependent on the concentration of solute particles and temperature, making it indirectly related to osmotic pressure through the Van 't Hoff equation.

## 3. What is the significance of osmotic pressure in biological systems?

Osmotic pressure plays a crucial role in maintaining the balance of fluids within living organisms. It determines the movement of water and nutrients across cell membranes, which is essential for proper cellular function. In addition, it helps regulate blood pressure and assists in the removal of waste products from the body.

## 4. How does temperature affect osmotic pressure?

According to the Van 't Hoff equation, osmotic pressure is directly proportional to temperature. As temperature increases, so does the osmotic pressure. This is because higher temperatures lead to increased kinetic energy of solute particles, which results in more collisions with the membrane and thus higher pressure.

## 5. Can osmotic pressure be used to determine the concentration of a solution?

Yes, osmotic pressure can be used to indirectly determine the concentration of a solution through the Van 't Hoff equation. By measuring the osmotic pressure of a solution and plugging it into the equation along with other known variables such as temperature and volume, the concentration of the solute particles can be calculated. This is a useful tool in various fields such as biochemistry and environmental science.

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