Plz help What is the molarity of 68.32g of H2SO4 in 500ml of solution?

Athe top of a hill, an athlete on a skateboard has x joules of mechanical energy. how much mechanical energy will she have at the bottom of the hill? ignore the effects of friction.

An electron moved from a lower energy level to a higher energy level. what most likely happened during the transition? a random amount of light was released. a fixed amount of energy was absorbed. a fixed amount of energy was released. a random amount of light was absorbed.

When utilizing a transmission electron microscope, why is it necessary to stain the specimen with heavy metal salts?