How are physical and chemical changes similar?
neither can change the number of atoms of each element that are present.
neither can cause chemical bonds to break.
neither can result in a phase change.
neither can cause a substance to give off heat or light
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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.