If a system has 2.00×10^2 kcal of work done to it, and releases 5.00×10^2 kJ of heat into its surroundings, what is the change in internal energy (ΔE or ΔU) of the system?

Which statement is actually true about the relationship between activation energy and reaction rates? low activation energy barriers result in low rates. high activation energy barriers result in low rates. low activation energy barriers result in no reaction. high activation energy barriers result in no reaction.