Which statement best explains why hydrogen’s atomic number is equal to its mass?(1 point) Hydrogen does not have any neutrons.

Hydrogen is in the first row and the first column of the periodic table.

Hydrogen has one electron and one proton.

Hydrogen is stable, with two electrons in its outer shell.

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.