Which statement about the enthalpy change (ΔH) of a chemical equation is correct when the equation is written in the opposite direction?
a) Both the magnitude and sign of ΔH remain the same.
b) The magnitude of ΔH doubles, and its sign changes.
c) The magnitude of ΔH remains the same, but its sign changes.
d) The magnitude of ΔH is halved, and the sign stays the same.