Out of the following different forms of oxygen, which will have the standard enthalpy of the formation to be 0.0 kJ;  O, O₂(g), O₃(g), O₂(l)?

Out of graphite and diamond, which one refers to the standard rate?

What is the value of enthalpy of neutralisation of a strong acid with a strong base?

Why the heat of neutralisation is less than 57.1 kJ if either the acid or the base or both are weak?

66.

What does the symbol  ∆_fH° denote?

What is the importance of ∆_fH°?

Will the heat evolved be same in the following two cases?


If not, in which case it will be greater and why?

Which of the following is/are exothermic and which is/are endothermic/