How many electrons will potassium gain during a chemical reaction

Two steel balls, each of mass m, are welded to a light rod of length l and negligible mass and are initially at rest on a smooth horizontal surface. a horizontal force of magnitude f is suddenly applied to the rod as shown. determine (a) the instantaneous acceleration a of the mass center g and (b) the corresponding rate at which the angular velocity of the assembly about g is changing with time.

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?

What happens to the vapor pressure of a substance when its surface area is increased at constant temperature?