The distribution of speeds for two samples of $\mathrm{N}_2$ gas. One sample is at 300 K, and the other is at 1000 K. Which is which?

One observable property of gases is the variability of density based on conditions. Use this observation to explain why hot air balloons rise.

Under what conditions do the postulates of the kinetic theory break down?

State the postulates of the kinetic theory of gases.

Clouds of hydrogen molecules have been detected deep in interstellar space. It is estimated that these clouds contain about $1 \times 10^{10}$ hydrogen molecules per $\mathrm{m}^3$ and have a temperature of just 25 K. Using these data, find the approximate pressure in such a cloud.

Ammonium dinitramide ( $\mathrm{ADN}), \mathrm{NH}_4 \mathrm{~N}\left(\mathrm{NO}_2\right)_2$, is being considered as a possible replacement for aluminum chloride as the oxidizer in the solid fuel booster rockets used to launch the space shuttle. When detonated by a spark, ADN rapidly decomposes to produce a gaseous mixture of $\mathrm{N}_2, \mathrm{O}_2$, and $\mathrm{H}_2 \mathrm{O}$. (This is not a combustion reaction. The ADN is the only reactant.) The reaction releases a lot of heat, so the gases are initially formed at high temperature and pressure. The thrust of the rocket results mainly from the expansion of this gas mixture. Suppose a 2.3-kg sample of $\mathrm{ADN}$ is detonated and decomposes completely to give $\mathrm{N}_2, \mathrm{O}_2$, and $\mathrm{H}_2 \mathrm{O}$. If the resulting gas mixture expands until it reaches a temperature of 100.0 degree C and a pressure of 1.00 atm, what volume will it occupy? Is your answer consistent with the proposed use of ADN as a rocket fuel?

As one step in its purification, nickel metal reacts with carbon monoxide to form a compound called nickel tetracarbonyl, $\mathrm{Ni}(\mathrm{CO})_4$, which is a gas at temperatures above about 316K. A 2.00-L flask is filled with CO gas to a pressure of 748 torr at 350.0 K, and then 5.00g of Ni is added. If the reaction described above occurs and goes to completion at constant temperature, what will the final pressure in the flask be?

Automakers are always investigating alternative reactions for the generation of gas to inflate air bags, in part because the sodium produced in the decomposition of $\mathrm{NaN}_3$ presents safety concerns. One system that has been considered is the oxidation of graphite by strontium nitrate, $\mathrm{Sr}\left(\mathrm{NO}_3\right)_2$, as shown in the equation below: $5 \mathrm{C}(\mathrm{s})+2 \mathrm{Sr}\left(\mathrm{NO}_3\right)_2(\mathrm{~s}) \rightarrow 2 \mathrm{SrO}(\mathrm{s})+2 \mathrm{~N}_2(\mathrm{~g})+5 \mathrm{CO}_2(\mathrm{~g})$ Suppose that a system is being designed using this reaction and the goal is to generate enough gas to inflate a bag to 61 L and 1.3 atm at $23^{\circ} \mathrm{C}$. What is the minimum mass of graphite that should be used in the design of this system?

During a collision, automobile air bags are inflated by the $\mathrm{N}_2$ gas formed by the explosive decomposition of sodium azide, $\mathrm{NaN}_3$.

$$2 \mathrm{NaN}_3 \rightarrow 2 \mathrm{Na}+3 \mathrm{~N}_2$$

What mass of sodium azide would be needed to inflate a 30.0-L bag to a pressure of 1.40 atm at 25 degree C ?

Magnesium will burn in air to form both $\mathrm{Mg}_3 \mathrm{~N}_2$ and MgO. What mass of each product would be found if burning a 3.11-g sample of magnesium to completion produces a combined total of 5.09 g of the two products?

What volume of hydrogen gas, in liters, is produced by the reaction of 3.43 g of iron metal with 40.0 mL of 2.43 M HCl? The gas is collected at 2.25 atm of pressure and 23 degree C. The other product is FeCl2.

Consider the following reaction.

$$6 \mathrm{NiO}(\mathrm{s})+4 \mathrm{ClF}_3(\mathrm{~g}) \rightarrow 6 \mathrm{NiF}_2(\mathrm{~s})+2 \mathrm{Cl}_2(\mathrm{~g})+3 \mathrm{O}_2(\mathrm{~g})$$

What mass of NiO will react with a sample of $\mathrm{ClF}_3$ gas that has a pressure of 250 torr in a 2.5-L flask at 20 degree C ?

Do a web search to identify which (if any) of the EPA’s criteria pollutants are prevalent in your city or state.

Ammonia is not the only possible fertilizer. Others include urea, which can be produced by the reaction, $\mathrm{CO}_2(\mathrm{~g})+$ $2 \mathrm{NH}_3(\mathrm{~g}) \rightarrow \mathrm{CO}\left(\mathrm{NH}_2\right)_2(\mathrm{~s})+\mathrm{H}_2 \mathrm{O}(\mathrm{g})$. A scientist has 75 g of dry ice to provide the carbon dioxide. If 4.50 L of ammonia at $15^{\circ} \mathrm{C}$ and a pressure of 1.4atm is added, which reactant is limiting? What mass of urea will form?