Question

For which reaction, carried out at standard conditions, wouldboth the enthalpy and entropy changes drive the reaction in thesame direction? Please EXPLAIN.

A. 2H2(g) + O2(g) --->2H2O(l) ΔH = -571.1 kJ

B. 2Na(s) + Cl2(g)---->2NaCl(s) ΔH = -822.0kJ

C. N2(g) + 2O2(g) ---->2NO2(g) ΔH= +67.7 kJ

D. 2NH3(g) ----> N2(g) +3H2(g) ΔH= +92.4 kJ

Answer 1

If both the enthalpy change and the entropy change have the same sign, the reaction will be driven in the same direction.

Step-by-step explanation:

The enthalpy change (ΔH) and the entropy change (ΔS) are both factors that drive a reaction in a particular direction.

If both ΔH and ΔS have the same sign, the reaction will be driven in the same direction.

In other words, if both values are positive or both values are negative, the reaction will be spontaneous.

In the given reactions, we can examine the enthalpy and entropy changes:

A. 2H2(g) + O2(g) → 2H2O(l) ΔH = -571.1 kJ:

This reaction has a negative ΔH and positive ΔS, so both changes are driving the reaction in the same direction.

The correct answer is A.