Chapter 12: Intermolecular Forces: Liquids, Solids, and Phase Changes

The crystal structure of sodium is based on the body-centered cubic unit cell. What is the mass of one unit cell of Na?

KF has the same type of crystal structure as NaCl. The unit cell of KF has an edge length of 5.39 $\stackrel{\mathbf{°}}{\mathbf{A}}$. Find the density of KF.

Question: One way to purify gaseousH₂is to pass it under high pressure through the holes of a metal’s crystals structure. Palladium, which adopts a cubic closest packed structure, absorbsH₂ than any other element and is one of the metals currently used for this purpose. Although the metal-hydrogen interaction is unclear, it is estimated that the density of absorbed H₂approaches that of liquid hydrogen (70.8g/L). what volume (in L) of gaseous H₂measured at STP, can be packed into the spaces of of palladium metal?

A liquid is in equilibrium with its vapour in a closed vessel at a fixed temperature. The vessel is connected by a stopcock to an evacuated vessel. When the stopcock is opened, will the final pressure of the vapour be different from the initial value if

(a) Some liquid remains

(b) All the liquid is first removed?

The phase diagram for substance A has a solid-liquid line with a positive slope, and that for substance B has a solid-liquid line with a negative slope. What macroscopic property can distinguish A from B?

Why does water vapour at${\mathbf{100}}^o\mathbf{C}$cause a more severe burn than liquid water at${\mathbf{100}}^o\mathbf{C}$?

From the data below, calculate the total heat (in J) needed to convert 22.00 g of ice at -6.00${}^o\mathbf{C}$to liquid water at 0.500role="math" localid="1656932965168" ${}^o\mathbf{C}$: M.P at 1 atm: 0.0role="math" localid="1656932982163" ${}^o\mathbf{C}$; ${\mathbf{\Delta H}}_{\mathrm{fus}}$: 6.02 kJ/mol;role="math" localid="1656932845775" ${\mathbf{Cl}}_{\mathrm{iquid}}$: 4.21 J/g${}^o\mathbf{C}$; ${\mathbf{C}}_{\mathrm{solid}}$: 2.09 J/g${}^o\mathbf{C}$

How does the energy of attraction between particles compare with their energy of motion in a gas and in a solid? As part of your answer, identify two macroscopic properties that differ between a gas and a solid.

From the data below, calculate the total heat (in J) needed to convert 0.333 mole of gaseous ethanol at ${300}^o\mathbf{C}$ and 1 atm to liquid ethanol at role="math" localid="1656934322575" $25{.0}^{\mathrm{o}}\mathrm{C}$and 1 atm: B.P. at 1 atm: ,$78{.5}^o\mathbf{C}$;${\mathbf{\Delta H}}_{\mathrm{yap}}$: 40.5 kJ/mol;: ${\mathbf{C}}_{\mathrm{gas}}$1.43 J/role="math" localid="1656934528476" ${\mathbf{g}}^o\mathbf{C}$;: 2.45 J/${\mathbf{g}}^o\mathbf{C}$.

A liquid has a ${{\mathbf{\Delta H}}^o}_{\mathrm{vap}}$ of 35.5 kJ/mole and a boiling point of $\mathbf{122}\mathbf{°}\mathbf{C}$at 1.00 atm. What is its vapour pressure at $\mathbf{113}\mathbf{°}\mathbf{C}$ ?