I am doing my lab report for thermodynamic of borax..my lecturer said that my calculation is correct but I got the resut at higher temperature,low ksp ang when low temperature the ksp higher..1.what usually error during the experiment? 2. can you explain the theory of temperature vs ksp?

The solubility product constant ?Ksp?? should increase as you increase the temperature. As to what went wrong with your experiment, is what applies to all experiments-- it takes a lot of effort in isolating just the two variables you are dealing with. ?Ksp?? should be measured at the exact instant the temperature is measured while keeping all the variables that also affect ?Ksp?? constant: pressure and composition. Pressure change was most likely minimal during your experiment, but a bit of impurities in your solution will significantly affect solubility.

Step-by-step explanation

When performing an experiment, specially involving chemicals, your environment must be as clean as possible. A tiny spec of solid significantly affects solubility. That is why a bit of salt causes a saturated cloud let go of water it can hold before. In your experiment, it may came from dust, or you may have scratched your container while mixing. You also have to make sure that your solution achieved maximum solubility before you have measured i.e. there are undissolved solids at the bottom.

When temperature is increased, the kinetic energy of the molecules in your solution increases. It makes the solvent molecules to more effectively break the intermolecular forces that holds the solutes together. The concentration of the products increases causing ?Ksp?? to increase.

?Ksp?=[Na2?borate][Na+]2[borate2−]??

The numerator increases, while the denominator is constant (or not even included in calculation, usually removed).