I have 2 questions. Can someone confirm my answers?
1.) Which of the following would almost always indicate a spontaneous reaction?
A.) when a reaction requires the input of energy
B.) if delta G is positive
C.) when enthalpy is positive and entropy is negative
D.) an exothermic reaction at low temperature
Is the answer D? Can someone please check?
2.) In nature, most spontaneous reactions are _____________ because the products are ____________ stable than the reactants.
Is the answer (exothermic, more)?
I agree with both answers.
1) To determine which option indicates a spontaneous reaction, you need to understand the concept of Gibbs free energy (ΔG). A spontaneous reaction occurs when ΔG is negative. Let's evaluate each option:
A) If a reaction requires the input of energy, it means ΔG is positive, and the reaction is non-spontaneous.
B) When ΔG is positive, it indicates a non-spontaneous reaction.
C) For a spontaneous reaction, the enthalpy (ΔH) must be negative, indicating an exothermic process, and the entropy (ΔS) must be positive, indicating an increase in disorder. Thus, when enthalpy is positive and entropy is negative, the reaction is non-spontaneous.
D) An exothermic reaction at low temperature could still be non-spontaneous if the decrease in enthalpy (exothermic release) is not enough to overcome the decrease in entropy (low temperature restricts disorder). Therefore, this option is not always indicative of a spontaneous reaction.
Based on this assessment, the correct answer would be: None of the above options always indicate a spontaneous reaction.
2) In nature, most spontaneous reactions are exothermic because the products are more stable than the reactants. This statement is correct. Spontaneous reactions typically release energy and occur because the products have lower energy and are more stable compared to the reactants.