Chloroform, $\mathrm{CHCl}_3$, a volatile liquid, was once used as an anesthetic but has been replaced by safer compounds. Chloroform boils at $61.7^{\circ} \mathrm{C}$ and has a heat of vaporization of $31.4 \mathrm{~kJ} / \mathrm{mol}$. What is its vapor pressure at $36.2^{\circ} \mathrm{C}$ ?

If atoms of a metallic element react with atoms of a nonmetallic element, which element loses electrons and which element gains them?

Steam at $100^{\circ} \mathrm{C}$ was passed into a flask containing $275 \mathrm{~g}$ of water at $21^{\circ} \mathrm{C}$, where the steam condensed. How many grams of steam must have condensed if the temperature of the water in the flask was raised to $83^{\circ} \mathrm{C}$ ? The heat of vaporization of water at $100^{\circ} \mathrm{C}$ is $40.7 \mathrm{~kJ} / \mathrm{mol}$ and the specific heat is $4.18 \mathrm{~J} /\left(\mathrm{g} \cdot{ }^{\circ} \mathrm{C}\right)$.

Liquid butane, $C_4H_{10}$, is stored in cylinders to be used as a fuel. Suppose 39.3 g of butane gas is removed from a cylinder. How much heat must be provided to vaporize this much gas? The heat of vaporization of butane is 21.3 kJ/mol.

Water at $0^{\circ} \mathrm{C}$ was placed in a dish inside a vessel maintained at low pressure by a vacuum pump. After a quantity of water had evaporated, the remainder froze. If $9.31 \mathrm{~g}$ of ice at $0^{\circ} \mathrm{C}$ was obtained, how much liquid water must have evaporated? The heat of fusion of water is $6.01 \mathrm{~kJ} / \mathrm{mol}$ and its heat of vaporization is $44.9 \mathrm{~kJ} / \mathrm{mol}$ at $0^{\circ} \mathrm{C}$.

Liquid butane, $C_4H_{10}$, is stored in cylinders to be used as a fuel. Suppose 39.3 g of butane gas is removed from a cylinder. How much heat must be provided to vaporize this much gas? The heat of vaporization of butane is 21.3 kJ/mol.

Isopropyl alcohol, $\mathrm{CH}_3 \mathrm{CH} \mathrm{OH} \mathrm{CH}_3 \mathrm{CH}_3$ , is used in rubbing alco hol mixtures. Alco hol on the skin cools by evaporation . How much heat is absorbed by the alco hol if 2.25 g evaporates? The heat of vaporization of isopropyl alcohol is 42.1 kJ/mol.

A 35.8-g sample of cadmium metal was melted by an electric heater providing $4.66 \mathrm{~J} / \mathrm{s}$ of heat. If it took $6.92 \mathrm{~min}$ from the time the metal began to melt until it was completely melted, what is the heat of fusion per mole of cadmium?

Estimate the value of x at which f increases most rapidly. Then find the exact value.

$$f(x)=x^2e-^x$$

Describe how you could liquefy the following gases: a. methyl chloride, $\mathrm{CH}_3 \mathrm{Cl}$ (critical point, $144^{\circ} \mathrm{C}$, 66 atm); b. oxygen, $\mathrm{O}_2$ (critical point, $-119^{\circ} \mathrm{C}, 50 \mathrm{~atm}$ ).

Explain why $15 \mathrm{~g}$ of steam at $100^{\circ} \mathrm{C}$ melts more ice than $15 \mathrm{~g}$ of liquid water at $100^{\circ} \mathrm{C}$.

Identify the phase transition occurring in each of the following.

a. Mothballs slowly become smaller and eventually disappear. b. Rubbing alcohol spilled on the palm of the hand feels cool as the volume of liquid decreases. c. A black deposit of tungsten metal collects on the inside of a lightbulb whose filament is tungsten metal. d. Raindrops hit a cold metal surface, which becomes covered with ice. e. Candle wax turns to liquid under the heat of the candle flame. 11.39 Use Figure $11.7$ to estimate the boiling point of diethyl ether, $\left(\mathrm{C}_2 \mathrm{H}_5\right)_2 \mathrm{O}$, under an external pressure of $350 \mathrm{mmHg}$.

Consider two flasks that contain different pure liquids at $20^{\circ} \mathrm{C}$

The liquid in one flask, substance $\mathrm{A}$, has a molar mass of $100 \mathrm{~g} / \mathrm{mol}$ and has hydrogen bonding. The liquid in the other flask, substance B, has a molar mass of $105 \mathrm{~g} / \mathrm{mol}$ and has dipole-dipole interactions. a.. If the molecular structures of the compounds are very similar, which flask probably contains substance $\mathbf{A}$ ? b. If you were to increase the temperature of each of the flasks by $15^{\circ} \mathrm{C}$, how would the pictures change (assume that you stay below the boiling points of the liquids)?

When hypothetical element $\mathrm{X}$ forms a solid, it can erystallae in three ways: with unit celis being either simple cuhic, face-centered cubic, of body-centered cuble.

a. Which crystalline form of solid $\mathrm{X}$ has the highest dersity? b. Which crystalline form of solsd $\mathrm{X}$ has the mont empty space?