Which of the following is true A closed thermodynamic system
     Which of the following is true?  A closed thermodynamic system can gain energy in the form of heat and work  A closed thermodynamic system can gain energy in the form of mass and work  A closed thermodynamic system can gain energy in the form of heat and mass  None of the above 
  
  Solution
First option because closed system can\'t exchange matter with surroundings

