Doubts regarding solubility product problem

In summary, the conversation discusses the calculation of concentration after dilution and the role of volume in this calculation. It is explained that the volume does not matter as long as two equal volumes are mixed, and that using a volume of 1L is easier for further calculations. It is also mentioned that the concentration can be divided by the number of solutions if they are of equal volume, and that dilution involves calculating the number of moles and dividing by the final volume.
  • #1
gracy
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As I am also attaching solution along with the problem there is no point in posting this thread in homework forums .
In the following question (solution is also there) https://s29.postimg.org/omlnt73lz/IMG_20170407_090748.jpg https://s18.postimg.org/hsuxm5uvt/IMG_20170407_090805.jpg why are we taking volume= 2 ? I know it's a mixture of two solutions of equal volumes but it's no where mentioned in the question that volume of each solution is 1 litre .
Another query regarding the Same problem is that why are we even bothered about the volume?we are directly given the concentrations of Ag and Cl (in the options. just look at the units , it's M that means molarity which is unit of concentration.) If it would have been number of moles then we would have required to divide it by volume to get concentration. Please Clear my doubts.
 
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  • #2
1. It doesn't matter what the volume is - as long as you mix two equal volumes when trying to calculate concentration after the dilution you will get something like [itex]\frac V {V+V}[/itex] where the V cancels out leaving you with [itex]\frac 1 2[/itex]. As V cancels out, we can safely ignore it.

2. They never assumed the volume to be 1 L, they just halved the concentration for the reason explained above.

3. But then, actually there is nothing wrong with assuming volume of 1L (or any other). All that is important is that you assume equal volumes and 1L is much easier to use in further calculations than - say - 2.7641 gallons.
 
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  • #3
Borek said:
1. It doesn't matter what the volume is - as long as you mix two equal volumes when trying to calculate concentration after the dilution you will get something like VV+VVV+V\frac V {V+V} where the V cancels out leaving you with 1212\frac 1 2. As V cancels out, we can safely ignore it.
If there will be mixture of three solutions of equal volume we will divide it by 3, right?

gracy said:
Another query regarding the Same problem is that why are we even bothered about the volume?we are directly given the concentrations of Ag and Cl (in the options. just look at the units , it's M that means molarity which is unit of concentration.) If it would have been number of moles then we would have required to divide it by volume to get concentration. Please Clear my doubts.
Please try to answer this as well.
 
  • #4
gracy said:
If there will be mixture of three solutions of equal volume we will divide it by 3, right?

Try to derive it.

Please try to answer this as well.

I don't understand where the problem is. Yes, we are given concentrations, but we have to calculate dilution. And calculating dilution is nothing else but calculating how much substance is put into the final solution (number of moles) and then dividing by the final volume. Yes, to speed up things we often do tricks (like here - dividing by two), but this is just a shortcut to the full calculation.
 

Related to Doubts regarding solubility product problem

1. What is solubility product?

Solubility product is a measure of the maximum amount of a solute that can dissolve in a solvent at a given temperature and pressure. It is represented by the mathematical expression Ksp.

2. What is the significance of solubility product in chemistry?

Solubility product is important in determining the solubility and precipitation of ionic compounds in solution. It is also used to calculate the concentration of ions in a saturated solution, which can provide insight into the chemical equilibrium of a system.

3. How do you calculate solubility product?

Solubility product is calculated by multiplying the concentrations of the ions in a saturated solution, each raised to the power of their respective coefficients in the balanced chemical equation. This can be determined experimentally or by using the solubility product constant (Ksp) values provided in tables.

4. What factors affect solubility product?

The solubility product of a compound is affected by temperature, pressure, and the presence of other ions in solution. Higher temperatures and pressures typically increase solubility, while the presence of other ions can cause a shift in the equilibrium of the system and affect the solubility product value.

5. What is the difference between solubility product and solubility?

Solubility refers to the maximum amount of a solute that can dissolve in a solvent at a given temperature and pressure, while solubility product is a specific value that represents the equilibrium between the dissolved solute and the solid precipitate. Solubility product is a constant for a specific compound, while solubility can vary depending on external conditions.

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