Chapter 12 quiz

According to the second law of thermodynamics, the change in the entropy of the universe (ΔS_univ) during a spontaneous reaction is

• zero.

• negative.

• positive.

• less than the change in entropy of the system (ΔS_sys).

• greater than the change in entropy of the system (ΔS_sys).

Which of the relationships between the free energy change of a system and associated entropy changes is true?

• ΔG_sys = +TΔS_sys

• ΔG_sys = -TΔS_sys

• ΔG_sys = +TΔS_univ

• ΔG_sys = -TΔS_univ

• ΔG_sys = -TΔS_surr

Which of the following is the best definition of a microstate as it pertains to entropy on the molecular level?

• the state (solid, liquid, or gas) of a small cluster of atoms or molecules

• a property of a small cluster of atoms and molecules, such as temperature, that is independent of how the property was achieved

• the set of vibrational, rotational, and translational energy levels in a system

• a unique specification of the vibrational, rotational, and translational states of a single molecule in a system

• a unique specification of the vibrational, rotational, and translational states of all the particles in a system

When the volume of a gas is increased, the energy separation between microstates

• increases.

• decreases.

• remains unchanged.

• becomes infinite.

• disappears.

The enthalpy of fusion for benzene, C6H6, is 127.34 kJ/kg, and its melting point is 5.49°C. Estimate ΔG° when 1.00 mole of benzene melts at 25.00°C.

• -8.31 kJ

• -0.696 kJ

• -11.3 kJ

• -0.831 kJ

• 117 kJ

For the dimerization of nitrogen dioxide to form dinitrogen tetroxide (N2O4) according to the reaction 2 NO2(g) ⇌ N2O4(g), the value of ΔH° is -57.2 kJ/mol, and that of ΔS° is -175.8 J/mol·K. Estimate ΔG° at 100.00°C.

• +6.6 kJ/mol

• -3.9 kJ/mol

• -122.8 kJ/mol

• -74.8 kJ/mol

• +8.4 kJ/mol

Tags

NGSS.HS-PS1-4

The enthalpy and entropy of vaporization of ammonia at its normal boiling point, –33.34°C, are 23.35 kJ/mol and 97.4 J/mol·K, respectively. What is the entropy change of the universe when one mole of liquid ammonia vaporizes in a large room maintained at 34.0°C? Assume the final temperature of the ammonia gas is –33.34°C.

• +21.4 J/K

• +76.0 J/K

• +74.1 J/K

• –21.4 J/K

• +76.0 J/K

Calculate the maximum amount of work that can be done by the reaction CH4(g) + 2 O2(g) ⇌ CO2(g) + 2 H2O(g) given the following information. Substance ΔGf°(kJ/mol) CH4(g) –50.8 CO2(g) –394.4 H2O(g) –228.57

• –673.8 kJ/mol

• –750.9 kJ/mol

• –902.3 kJ/mol

• –216.6 kJ/mol

• –800.7 kJ/mol

Tags

NGSS.HS-PS1-4