The partial pressure of carbon dioxide varies with seasons. Would you expect the partial pressure in the northern hemisphere to be higher in the summer or winter? Explain.

Helium is mixed with oxygen gas for deep-sea divers. Calculate the percent by volume of oxygen gas in the mixture if the diver has to submerge to a depth where the total pressure is $4.2$ bar. The partial pressure of oxygen is maintained at $0.20$ bar at this depth.

A piece of sodium metal reacts completely with water as follows:

$$2 \mathrm{Na}(s)+2 \mathrm{H}_2 \mathrm{O}(l) \longrightarrow 2 \mathrm{NaOH}(a q)+\mathrm{H}_2(\mathrm{~g})$$

The hydrogen gas generated is collected over water at $25.0^{\circ} \mathrm{C}$. The volume of the gas is $246 \mathrm{~mL}$ measured at $1.00$ bar. Calculate the number of grams of sodium used in the reaction. (Vapor pressure of water at $25^{\circ} \mathrm{C}$ is $0.0310$ bar.)

A mixture of helium and neon gases is collected over water at $28.0^{\circ} \mathrm{C}$ and 745 torrs. If the partial pressure of helium is 368 torr, what is the partial pressure of neon? (Vapor pressure of water at $28^{\circ} \mathrm{C}$ is $28.3$ torr.)

Dry air near sea level has the following composition by volume: $\mathrm{N}_2, 78.08$ percent; $\mathrm{O}_2, 20.94$ percent; Ar, $0.93$ percent; and $\mathrm{CO}_2, 0.05$ percent. The atmospheric pressure is $1.00 \mathrm{~atm}$. Calculate
the concentration of each gas in mol $\mathrm{L}^{-1}$ at $0^{\circ} \mathrm{C}$.

Dry air near sea level has the following composition by volume: $\mathrm{N}_2, 78.08$ percent; $\mathrm{O}_2, 20.94$ percent; Ar, $0.93$ percent; and $\mathrm{CO}_2, 0.05$ percent. The atmospheric pressure is $1.00 \mathrm{~atm}$. Calculate
the partial pressure of each gas in atm.

A $2.5-\mathrm{L}$ flask at $15^{\circ} \mathrm{C}$ contains a mixture of $\mathrm{N}_2$. $\mathrm{He}$, and $\mathrm{Ne}$ at partial pressures of $0.32$ bar for $\mathrm{N}_2$. $0.15$ bar for He, and $0.42$ bar for Ne.
Calculate the volume in liters at SATP occupied by He and Ne if the $\mathrm{N}_2$ is removed selectively.

A $2.5-\mathrm{L}$ flask at $15^{\circ} \mathrm{C}$ contains a mixture of $\mathrm{N}_2$. $\mathrm{He}$, and $\mathrm{Ne}$ at partial pressures of $0.32$ bar for $\mathrm{N}_2$. $0.15$ bar for He, and $0.42$ bar for Ne.
Calculate the total pressure of the mixture.

The boiling point and freezing point of sulfur dioxide at 1 bar are $-10^{\circ} \mathrm{C}$ and $-72.7^{\circ} \mathrm{C}$, respectively. The triple point is at $-75.5^{\circ} \mathrm{C}$ and $1.67 \times 10^3$ bar, and its critical point is at $157^{\circ} \mathrm{C}$ and 79 bar. On the basis of this information, draw a rough sketch of the phase diagram of $\mathrm{SO}_2$.

When ammonium nitrite $\left(\mathrm{NH}_4 \mathrm{NO}_2\right)$ is heated, it decomposes to give nitrogen gas. This property is used to inflate some tennis balls.
Calculate the quantity (in grams) of $\mathrm{NH}_4 \mathrm{NO}_2$ needed to inflate a tennis ball to a volume of $86.2 \mathrm{~mL}$ at $1.20$ bar and $22^{\circ} \mathrm{C}$.

When ammonium nitrite ($\mathrm{NH_4NO_2}$) is heated, it decomposes to give nitrogen gas. This property is used to inflate some tennis balls. Write a balanced equation for the reaction.

The empirical formula of a compound is $\mathbf{C H}$. At $200^{\circ} \mathrm{C}, 0.145 \mathrm{~g}$ of this compound occupies $97.2 \mathrm{~mL}$ at a pressure of $0.74 \mathrm{~atm}$. What is the molecular formula of the compound?

Nitroglycerin, an explosive compound, decomposes according to the equation

$$\begin{aligned} &4 \mathrm{C}_3 \mathrm{H}_5\left(\mathrm{NO}_3\right)_3(\mathrm{~s}) \longrightarrow \\ &12 \mathrm{CO}_2(\mathrm{~g})+10 \mathrm{H}_2 \mathrm{O}(\mathrm{g})+6 \mathrm{~N}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \end{aligned}$$

Calculate the total volume of gases when collected at $1.2$ bar and $25^{\circ} \mathrm{C}$ from $2.6 \times 10^2 \mathrm{~g}$ of nitroglycerin. What are the partial pressures of the gases under these conditions?

Under the same conditions of temperature and pressure which of the following gases would behave most ideally: $\mathrm{Ne}, \mathrm{N}_2$, or $\mathrm{CH}_4$? Explain.