All of the following have a standard heat of formation value of zero at 25 °C and 1.0 atm except:

In a cyclic process, the total change in internal energy is zero

Q18 and Q19.png A fixed amount of ideal gas changes from state A to state B along an isothermal process, as shown in the p–V diagram below: Answer the following questions 18 and 19: Q18: Which of the following statements is correct?

when standard molar enthalpy is less than zero, the reaction is endothermic

In the van der Waals equation, the parameter corrects for which assumption of the ideal gas law?i. No intermolecular forces exist.ii. Collisions with container walls are perfectly elastic.iii. Gas molecules undergo random thermal motion.iv. Gas molecules occupy no volume.

For ideal and non-ideal gases, which one of the following is correct? 

The internal energy change of an ideal gas depends not only on its temperature, but also its volume or pressure.

Based on the first law of thermodynamics, which of the following statement is correct?

At 273 K and standard pressure (pθ), during the melting of ice into water, which of the following relationships is correct?

For CO(g) + 1/2 O2(g) → CO2(g), the enthalpy change is ΔH. Which statement is incorrect?