Chemistry

2019 U.S. National Chemistry Olympiad Local Section Exam Question 22

For a constant-pressure process, what is the difference between the internal energy change (∆U) and the enthalpy change (∆H)?

(A) Heat
(B) Work
(C) Entropy
(D) Gibbs free energy
Chemistry

A liquid will boil when

(A) its freezing point is equal to its melting point
(B) a salt has been added to the liquid
(C) its vapor pressure is equal to the melting point
(D) it is heated to a temperature that is below the boiling point
(E) its vapor pressure is equal to the surrounding pressure