Which of the following statements is always true? 1. If ∆H0 and ∆S 0 are both positive, ∆G 0 will decrease as the temperature increases. 2. If the number of moles of gas does not change in a chemical reaction, then ∆S 0 = 0. 3. A reaction for which ∆S 0 is positive is spontaneous. 4. An exothermic reaction is spontaneous.