Which statement concerning reactions is correct?
- AA reaction in which the number of bonds broken equals the number of bonds formed always has an enthalpy change, $\Delta H = 0$.
- BCombustion can be either exothermic or endothermic.
- CIn exothermic reactions, thermal energy is transferred to the surroundings, so the temperature of the surroundings increases.
- DThe activation energy, $E_a$, for a reaction is the minimum energy particles must have in order to collide.