Question

Which choice contains a FALSE statment? A. For the vaporization of liquid benzene ΔH is positive. B. For the formation of 1 mol nitrogen dioxide from its elements (heat is absorbed)ΔH is negative. C. For the sublimation of dry ice [conversion of CO₂(s) directly to CO₂(g)] ΔH is positive. D. For the reaction of 1 mol of sulfur dioxide with oxygen ΔH is negative. E. None of these is/are FALSE

Answer 1

Answer:

B is False

Explanation:

In physical chemistry we always look from system's perspective, so if we heat something ΔH is positive and if the system gives heat out then ΔH is negative.

A. We have to give energy to benzene to evaporate it. Statement true.

B. If heat is absorbed then the enthalpy must be positive.

C. The heat is absorbed then ΔH is positive.

D. Usually for burning heat is exposed from system. So enthalpy is negative.

E. Obvious