ACS PHYSICAL CHEMISTRY THERMOCHEMISTRY ACTUAL EXAM PAPER 2026 SOLVED RESPONSES GRADED A+

ACS PHYSICAL CHEMISTRY
THERMOCHEMISTRY ACTUAL EXAM PAPER
2026 SOLVED RESPONSES GRADED A+

◉ 2nd law of thermodynamics. Answer: Every energy transfer or
transformation increases the entropy of the universe.


◉ 3rd law of thermodynamics. Answer: No system can reach
absolute zero


◉ Enthalpy. Answer: The heat content of a system at constant
pressure. the sum of the internal energy and the product of pressure
and volume


◉ Enthalpy formula. Answer: ΔH = ΔU + Δ(PV)
H = U + PV


◉ Entropy. Answer: A measure of disorder or randomness of a
system.


◉ Entropy formula for an ideal gas expanding isothermally. Answer:
S = nRln(V2/V1)

, ◉ Entropy formula for a phase change at constant pressure. Answer:
ΔS = q/T


◉ Boltzmann equation for entropy. Answer: S=klnW
k=1.38*10^-23J/K
W=# of microstates


◉ State functions. Answer: properties that are determined by the
state of the system, regardless of how that condition was achieved
(U, H, S, G)


◉ Work expansion at constant P (external). Answer: w=-PΔV


◉ Work of free expansion. Answer: w=0


◉ Work of isothermal reversible expansion. Answer: w=-
nRTln(Vf/Vi)


◉ heat at constant pressure equation. Answer: energy transferred
from one system to another. Q=mcΔT


◉ Internal energy. Answer: total energy of a system