## Chemistry: A Molecular Approach (3rd Edition)

If the enternal energy of the products of the reaction is higher than the internal energy of the reactants the $ΔE$ must be positive. Energy flows into the system from the surroundings.
$ΔE_{System}$ = $ΔE_{Final}$ $-$ $ΔE_{Initial}$ If $ΔE_{Final}$ $\gt$ $ΔE_{Initial}$ then $ΔE_{System}$ will be positive.