Asolution of saturated pbi2 is found to contain 2.7 ✕ 10−3 m iodide ion. calculate the ksp of pbi2

When the compound PbI₂ dissolves, it dissociates as follows;
PbI₂ --> Pb²⁺ + 2I⁻
Molar solubility is the number of moles dissolved in 1 L of solution
A saturated solution is when the maximum amount of solute is dissolved in the solution.
Molar solubility of Iodide when solution is saturated is 2.7 x 10⁻³ mol/L, then solubility of Pb²⁺ is (2.7 x 10⁻³ mol/L) / 2 = 1.35 x 10⁻³ mol/L
ksp is the solubility product constant that can be calculated as follows;
ksp = [Pb²⁺][I⁻]
ksp = (1.35 x 10⁻³ mol/L) x (2.7 x 10⁻³ mol/L)²
      = 1.35 x 10⁻³ x 7.29 x 10⁻⁶
      = 9.8 x 10⁻⁹ 

Yes, endothermic means it turns cold. and some chemical changes include change of tempature.

Okay well gravitational energy is matter forced by gravity making energy though the kinetic energy then the electric energy produces electricity from the kinetic energy and the kinetic energy gets its energy from the gravitational energy. was that the answer you wanted or something else?