Question

Which of the reactions are spontaneous (favorable)? A. DHAP↽−−⇀glyceraldehyde-3-phosphateΔ????=3.8 kJ/mol B. C2H4+H2−→−−Rh(I)C2H6Δ????=−150.97 kJ/mol C. glutamate+NAD++H2O⟶NH+4+α-ketoglutarate+NADH+H+Δ????=3.7 kcal/mol D. C6H13O9P+ATP⟶C6H14O12P2+ADPΔ????=−14.2 kJ/mol E. L -malate+NAD+⟶oxaloacetate+NADH+H+Δ????=29.7 kJ/mol

Answer 1

Answer:

The spontaneous reactions are:

B. $C_{2}H_{4} + H_{2} \overset{Rh(I)}{\rightarrow}C_{2}H_{6}$ ; ΔG= −150.97 kJ/mol  

D. C₆H₁₃O₉P + ATP ⟶ C₆H₁₄O₁₂P₂ + ADP; ΔG = −14.2 kJ/mol  

Explanation:  

Gibbs free energy , denoted by ΔG, is the quantitative measure of the favorability or spontaneity of a given process or chemical reaction that is carried out at constant temperature (T) and pressure (P).

Therefore, Gibbs free energy in J: ΔG = ΔH - TΔS

Here, ΔH is the change in enthalpy and ΔS is the change in the entropy

For a given chemical reaction to be spontaneous or favorable, ΔG should be negative (ΔG < 0).

A. DHAP ⇌ glyceraldehyde-3-phosphate ; ΔG = 3.8 kJ/mol  

The value of ΔG is positive (ΔG > 0). Therefore, this reaction is not spontaneous.

B. $C_{2}H_{4} + H_{2} \overset{Rh(I)}{\rightarrow}C_{2}H_{6}$ ; ΔG= −150.97 kJ/mol  

 The value of ΔG is negative (ΔG < 0). Therefore, this reaction is spontaneous.

C. glutamate + NAD⁺ + H₂O ⟶ NH⁴⁺ +α-ketoglutarate + NADH + H⁺ ; ΔG = 3.7 kcal/mol  

The value of ΔG is positive (ΔG > 0). Therefore, this reaction is not spontaneous.

D. C₆H₁₃O₉P + ATP ⟶ C₆H₁₄O₁₂P₂ + ADP; ΔG = −14.2 kJ/mol  

 The value of ΔG is negative (ΔG < 0). Therefore, this reaction is spontaneous.

E. L -malate + NAD⁺ ⟶ oxaloacetate + NADH + H⁺; ΔG = 29.7 kJ/mol

The value of ΔG is positive (ΔG > 0). Therefore, this reaction is not spontaneous.