need this ASAP for my lab report. thank you so much

Lead (II) Chloride is only very slightly soluble in water. PbCl2(s)Pb2+(aq)+2Cl(aq) a. Write the equilibrium constant expression for the above reaction. b. When a test tube containing PbCl2(s) was placed in a beaker of hot water, the solid crystals disappeared. When the test tube was then place in cold water, the solid crystals reappeared. Based on these observations, is the above reaction endothermic or exothermic? Explain your