" What does A thandela thank the international leaders for? "

What does Mandela thank the international leaders for?

A system absorbs 50 kJ heat and does 20 kJ of work. What is the net change in the internal energy of the system ?

A system absorbs 50 kJ heat and does 20 kJ of work. What is the net change in the internal energy of the system ?

A certain reaction is exothermic by 220kJ and does 10kJ of work. What is the change is the internal energy of the system at constant temperture?