Can a physical change, change what a substance is

Each pair of clay balls represents to planetesimals if each plane test molluscum pound of the same material and is separated by the same distance which pair experiences the greatest gravitational attraction

The molality of calcium chloride (cacl2) in an aqueous solution is 2.46 m. what is mole fraction of the solute?

Chlorine and water react to form hydrogen chloride and oxygen, like this: 2cl2 (g) + 2h2o (g) → 4hcl (g) + o2 (g) also, a chemist finds that at a certain temperature the equilibrium mixture of chlorine, water, hydrogen chloride, and oxygen has the following composition: compound concentration at equilibrium cl2 0.55m h2o 0.57m hcl 0.53m o2 0.34m calculate the value of the equilibrium constant kc for this reaction. round your answer to 2 significant digits.