Based on the equation for Gibbs Free Energy, there are certain reactions that are spontaneous at only low temperatures.
If ΔS, entropy, is negative, and ΔH, enthalpy, is negative, the reaction is spontaneous at low temperatures. Based on the equation ΔG = ΔH - TΔS, we want Gibbs free energy to be negative. This requires a low temperature because a negative change in entropy makes that term positive. If the temperature is high, Gibbs free energy is more likely to be positive.
If ΔS, entropy, is negative, and ΔH, enthalpy, is negative, the reaction is spontaneous at low temperatures. Based on the equation ΔG = ΔH - TΔS, we want Gibbs free energy to be negative. This requires a low temperature because a negative change in entropy makes that term positive. If the temperature is high, Gibbs free energy is more likely to be positive and the reaction is likely to be nonspontaneous.
Based on the equation for Gibbs Free Energy, there are certain reactions that are spontaneous at only high temperatures.
If ΔS, entropy, is positive, and ΔH, enthalpy, is positive, the reaction is spontaneous at high temperatures. Based on the equation ΔG = ΔH - TΔS, we want Gibbs free energy to be negative. This requires a high temperature because a positive change in enthalpy makes that term in the equation positive. If the temperature is high. In order for Gibbs free energy to be negative, the entropy term must be greater in magnitude than the enthalpy term, requiring a high temperature.
If ΔS, entropy, is positive, and ΔH, enthalpy, is positive, the reaction is spontaneous at high temperatures. Based on the equation ΔG = ΔH - TΔS, we want Gibbs free energy to be negative. This requires a high temperature because a positive change in enthalpy makes that term in the equation positive. If the temperature is high. In order for Gibbs free energy to be negative, the entropy term must be greater in magnitude than the enthalpy term, requiring a high temperature.
Some reactions are spontaneous at all temperatures depending on the values of enthalpy and entropy.
If ΔS, entropy, is positive, and ΔH, enthalpy, is negative, the reaction is spontaneous at all temperatures. This is because based on the equation ΔG = ΔH - TΔS, Gibbs free energy would always be negative. Thus, the reaction would always be spontaneous.
If ΔS, entropy, is positive, and ΔH, enthalpy, is negative, the reaction is spontaneous at all temperatures. This is because based on the equation ΔG = ΔH - TΔS, Gibbs free energy would always be negative. Thus, the reaction would always be spontaneous.
Some reactions will never be spontaneous as written based on the changes in entropy and enthalpy associated with them.
If ΔS, entropy, is negative, and ΔH, enthalpy, is positive, the reaction isnon spontaneous at all temperatures. This is because based on the equation ΔG = ΔH - TΔS, Gibbs free energy would always be positive and can never be negative. Thus, the reaction would always be nonspontaneous.
If ΔS, entropy, is negative, and ΔH, enthalpy, is positive, the reaction isnon spontaneous at all temperatures. This is because based on the equation ΔG = ΔH - TΔS, Gibbs free energy would always be positive and can never be negative. Thus, the reaction would always be nonspontaneous.
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