The normal melting point of copper is $1357 \mathrm{~K}$, and $\Delta_{\text {fus }} \mathrm{H}$ of $\mathrm{Cu}$ is $13.05 \mathrm{~kJ} \mathrm{~mol}^{-1}$. (a) How much heat, in kilojoules, is evolved when a $3.78 \mathrm{~kg}$ sample of molten Cu freezes?

As a liquid evaporated from an open container, its temperature was observed to remain roughly constant. When the same liquid evaporated from a thermally insulated container (a vacuum bottle or Dewar flask), its temperature was observed to drop. How would you account for this difference?

How many liters of $\mathrm{CH}_4(\mathrm{~g})$, measured at $23.4{ }^{\circ} \mathrm{C}$ and $768 \mathrm{mmHg}$, must be burned to provide the heat needed to vaporize $3.78 \mathrm{~L}$ of water at $100^{\circ} \mathrm{C}$ ? For $\mathrm{CH}_4 \Delta_{\text {comb }} \mathrm{H}=$ $-8.90 \times 102 \mathrm{~kJ} \mathrm{~mol}-1$. For $\mathrm{H} 20(1)$ at $100{ }^{\circ} \mathrm{C}, \mathrm{d}=0.958 \mathrm{~g} \mathrm{~cm}-3$, and ti vapH $=40.7$kJ mol-1

Use data from the Integrative Example (page 566) to determine how much heat is required to convert $25.00 \mathrm{~mL}$ of liquid hydrazine at $25.0^{\circ} \mathrm{C}$ to hydrazine vapor at its normal boiling point.

You decide to cool a can of soda pop quickly in the freezer compartment of a refrigerator. When you take out the can, the soda pop is still liquid; but when you open the can, the soda pop immediately freezes. Explain why this happens.

Potassium adopts the body-centered cubic unit cell in its crystal structure. If the atomic radius of potassium is 227 pm, find the edge length of the unit cell.

For each of the following substances describe the importance of dispersion (London) forces, dipole-dipole interactions, and hydrogen bonding: (a) $\mathrm{HCl}$;

Can S0$_2$ be maintained as a liquid under a pressure of $100 \mathrm{~atm}$ at $0^{\circ} \mathrm{C}$? Can liquid methane be obtained under the same conditions?

Which substances listed in Table 12.6 can exist as liquids at room temperature ($20^{\circ} \mathrm{C}$)? Explain.

Determine whether the statement is true or false. If it is false, rewrite it as a true statement. The number of different ordered arrangements of n distinct objects is n!.

Identifica la palabra o la frase que no pertenece al grupo. (Tell which word or phrase doesn’t belong in the group.) la plaza, el objeto, la ciudad, la avenida

With reference to Figure 12-20, which is the more volatile liquid, benzene or toluene? At approximately what temperature does the less volatile liquid have the same vapor pressure as the more volatile one at $65^{\circ} \mathrm{C}$ ? 46. Can $\mathrm{SO}_2$ be maintained as a liquid under a pressure of $100 \mathrm{~atm}$ at $0^{\circ} \mathrm{C}$ ? Can liquid methane be obtained under the same conditions?

Classify each of these solids.CaCl2, C(diamond), Ca, FCl. Answers can be ionic, molecular, metallic, or covalent.

Benzaldehyde, $\mathrm{C}_6 \mathrm{H}_5 \mathrm{CHO}$, has a normal boiling point of $179.0^{\circ} \mathrm{C}$ and a critical point at $422^{\circ} \mathrm{C}$ and $45.9 \mathrm{~atm}$. Estimate its vapor pressure at $100.0^{\circ} \mathrm{C}$.