Question

Question 14 (1 point) Which of the following has a standard enthalpy of formation of zero? OP(s, red) Br2(g) O3(g) 12(8) Arce)

Answer 1

P(s,red) and Ar(g) having zero standard enthalpy of formation.

The elements which are exists in their standard state at 273K and 1 atm pressure having zero standard enthalpy of formation.

Phosphorous exists in the solid state at standard conditions

Argon exists in the gaseous state at standard conditions.

Hence , these two elements have zero standard enthalpy of formation.

Bromine exists in liquid state at standard conditions.

Iodine exits in solid state at standard conditions.

O2 has zero value but O3 has some value of standard enthalpy of formation.