The element cesium (Cs) freezes at $28.4^{\circ} \mathrm{C}$, and its molar enthalpy of fusion is $\Delta H_{\text {fus }}=2.09 \mathrm{~kJ} / \mathrm{mol}$

When molten cesium solidifies to $\mathrm{Cs}(\mathrm{s})$ at its normal melting point, is $\Delta S$ positive or negative?

Suppose we vaporize a mole of liquid water at $25^{\circ} \mathrm{C}$ and another mole of water at $100^{\circ} \mathrm{C}$.

(b) Does the entropy change in either process depend on whether we carry out the process reversibly or not? Explain.

Suppose we vaporize a mole of liquid water at $25^{\circ} \mathrm{C}$ and another mole of water at $100^{\circ} \mathrm{C}$. (a) Assuming that the enthalpy of vaporization of water does not change much between $25^{\circ} \mathrm{C}$ and $100^{\circ} \mathrm{C}$, which process involves the larger change in entropy?

What is the sign of $\Delta S$ for the process?

Give an example of a process in which the entropy of the system decreases.

Two different gases occupy two separate bulbs. Consider the process that occurs when the stopcock separating the gases is opened, assuming the gases behave ideally.

How does the process affect the entropy of the surroundings?

Consider what happens when a sample of the explosive 'TNT' (Section 8.8: "Chemistry Put to Work: Explosives and Alfred Nobel") is detonated under atmospheric pressure.

(d) Can you determine the sign of $\Delta E$ for the process? Explain.

Consider what happens when a sample of the explosive 'TNT' (Section 8.8: "Chemistry Put to Work: Explosives and Alfred Nobel") is detonated under atmospheric pressure. (c) Is it possible to tell whether $w$ is positive, negative, or zero for the process? Explain.

Two different gases occupy two separate bulbs. Consider the process that occurs when the stopcock separating the gases is opened, assuming the gases behave ideally.

Is the process that occurs when the stopcock is opened a reversible one?

Two different gases occupy two separate bulbs. Consider the process that occurs when the stopcock separating the gases is opened, assuming the gases behave ideally.

Predict the signs of $\Delta H$ and $\Delta S$ for the process.

Consider what happens when a sample of the explosive 'TNT' (Section 8.8: "Chemistry Put to Work: Explosives and Alfred Nobel") is detonated under atmospheric pressure.

(b) What is the sign of $q$ for this process?

Consider what happens when a sample of the explosive 'TNT' (Section 8.8: "Chemistry Put to Work: Explosives and Alfred Nobel") is detonated under atmospheric pressure. (a) Is the detonation a spontaneous process?

Two different gases occupy two separate bulbs. Consider the process that occurs when the stopcock separating the gases is opened, assuming the gases behave ideally.

Draw the final (equilibrium) state.

Con sider a system consisting of an ice cube. If the ice cube melts reversibly, is

$$\Delta H$$

zero for the process?