Bubbles, release of gas, change in color, release of a smell, change in temperature, formation of a precipitate,
Answer is: temperature must be less than 140 K.
Gibbs free energy
(G) determines if reaction will proceed spontaneously. <span>If
the value of G is a negative, the reaction is spontaneous. <span>ΔG = ΔH - T·ΔS.
</span></span>ΔH = -70.00 kJ.
ΔS = -0.500 kJ/K.
-70 kJ = T · (-0.5 kJ/K).
T = -70.00 kJ ÷ (-0.500 kJ/K).
T = 140 K.
Actually, it could indeed be the independent variable.