Imagine a reaction A for which the values of ΔH and ΔS are both negative. It is known that the absolute value of ΔS is 3 times smaller than the absolute value of ΔH. For what values of T does reaction A occur spontaneously?

We know that a reaction occurs spontaneously when ΔG<0 and that ΔG=ΔH-TΔS. So, we know that the reaction will be spontaneous when ΔH<TΔS.Its is given that ΔH and ΔS are <0 and that |ΔH|=3*|S|. From this we can conclude that the inequation ΔH<TΔS will be true whenT< 3K. We also have to keep in mind that the temperature can never be lower than the absolute zero (0K) and so, the answer is 0K < T < 3K.