If the mass of 3 black beans it's 0.7 what's the mass of one bean?

An electron moved from shell n = 2 to shell n = 1. what most likely happened during the transition? a fraction of a photon was added. a photon of energy was absorbed. a fraction of a photon was removed. a photon of energy was released.

How do you identify the anode on a power source such as a battery? how do you identify the cathode? how are terms anion and cation?

How many moles of oxygen gas are produced from the decomposition of six moles of potassium