Why does half a mole of water molecules have more mass than 2 moles of helium atoms?

For a patient with the following pes statement and interventions, which would be the most appropriate monitoring and evaluating data? pes statement: inadequate calcium intake related to food and nutrition related knowledge deficit as evidenced by statements that the only dietary source of calcium is milk and she believes that she is lactose intolerant. patient’s nutrition prescription is for a diet providing 1200 mg calcium per day. patient was provided with in-depth nutrition education on alternative dietary and supplement sources of calcium. a. calcium intake (at subsequent visit) b. knowledge assessment by asking patient to identify food sources from menus and shopping list (at the end of the current visit) c. serum calcium (at next visit) d. both a and b e. both a and c

Compare and contrast physical changes with chemical changes.

Select all of the statements which are true. electrons are located in shells or orbits around the atom. electrons orbit slowly around the atom. electrons travel in one flat path around the nucleus of an atom. the valence of an atom is determined by the number of electrons in the atom's outermost shell.