A student lifts a backpack straight up from the ground to 1.2 m with a force of 45.5 N. How much work is done to the backpack? need formula and need work done

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

As air becomes more dense, (select all that apply) o. air weighs less o. gas molecules are closer together o. air is colder o. air weighs more o. gas molecules are further apart o. air is hotter

Which of the following is most likely true about water in chemical solutions?