Chapter 10

You want to store \(165 \mathrm{g}\) of \(\mathrm{CO}_{2}\) gas in a \(12.5-\mathrm{L}\) tank at room temperature \(\left(25^{\circ} \mathrm{C}\right) .\) Calculate the pressure the gas would have using (a) the ideal gas law and (b) the van der Waals equation. (For \(\mathrm{CO}_{2}\) \(\left.a=3.59 \text { atm } \cdot \mathrm{L}^{2} / \mathrm{mol}^{2} \text { and } b=0.0427 \mathrm{L} / \mathrm{mol} .\right)\)

Consider a 5.00 -L tank containing 375 g of Ar at a temperature of \(25^{\circ} \mathrm{C}\) (a) Calculate the pressure in the tank using both the ideal gas law and the van der Waals equation. (b) Which correction term, \(a(n / V)^{2}\) or \(b n,\) has the greatest influence on the pressure of this system?

On combustion, 1.0 L of a gaseous compound of hydrogen, carbon, and nitrogen gives \(2.0 \mathrm{L}\) of \(\mathrm{CO}_{2}, 3.5 \mathrm{L}\) of \(\mathrm{H}_{2} \mathrm{O}\) vapor, and \(0.50 \mathrm{L}\) of \(\mathrm{N}_{2}\) at STP. What is the empirical formula of the compound?

You have a sample of helium gas at \(-33^{\circ} \mathrm{C}\) and you want to increase the rms speed of helium atoms by \(10.0 \% .\) To what temperature should the gas be heated to accomplish this?

If \(12.0 \mathrm{g}\) of \(\mathrm{O}_{2}\) is required to inflate a balloon to a certain size at \(27^{\circ} \mathrm{C},\) what mass of \(\mathrm{O}_{2}\) is required to inflate it to the same size (and pressure) at \(5.0^{\circ} \mathrm{C} ?\)

A bicycle tire has an internal volume of \(1.52 \mathrm{L}\) and contains 0.406 mol of air. The tire will burst if its internal pressure reaches 7.25 atm. To what temperature, in degrees Celsius, does the air in the tire need to be heated to cause a blowout?

The temperature of the atmosphere on Mars can be as high as \(27^{\circ} \mathrm{C}\) at the equator at noon, and the atmospheric pressure is about \(8 \mathrm{mm}\) Hg. If a spacecraft could collect \(10 . \mathrm{m}^{3}\) of this atmosphere, compress it to a small volume, and send it back to Earth, how many moles would the sample contain?

If you place 2.25 g of solid silicon in a \(6.56-\mathrm{L}\) flask that contains \(\mathrm{CH}_{3} \mathrm{Cl}\) with a pressure of \(585 \mathrm{mm} \mathrm{Hg}\) at \(25^{\circ} \mathrm{C},\) what mass of dimethyldichlorosilane, \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiCl}_{2},\) can be formed? $$ \mathrm{Si}(\mathrm{s})+2 \mathrm{CH}_{3} \mathrm{Cl}(\mathrm{g}) \rightarrow\left(\mathrm{CH}_{3}\right)_{2} \operatorname{SiCl}_{2}(\mathrm{g}) $$ What pressure of \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiCl}_{2}(\mathrm{g})\) would you expect in this same flask at \(95^{\circ} \mathrm{C}\) on completion of the reaction? (Dimethyldichlorosilane is one starting material used to make silicones, polymeric substances used as lubricants, antistick agents, and water-proofing caulk.)

What volume (in liters) of \(\mathrm{O}_{2}\), measured at standard temperature and pressure, is required to oxidize 0.400 mol of phosphorus \(\left(P_{4}\right) ?\) $$ \mathrm{P}_{4}(\mathrm{s})+5 \mathrm{O}_{2}(\mathrm{g}) \rightarrow \mathrm{P}_{4} \mathrm{O}_{10}(\mathrm{s}) $$

Nitroglycerin decomposes into four different gases when detonated: $$4 \mathrm{C}_{3} \mathrm{H}_{5}\left(\mathrm{NO}_{3}\right)_{3}(\ell) \rightarrow 6 \mathrm{N}_{2}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g})+ 12 \mathrm{CO}_{2}(\mathrm{g})+10 \mathrm{H}_{2} \mathrm{O}(\mathrm{g}) $$ The detonation of a small quantity of nitroglycerin produces a total pressure of 4.2 atm at a temperature of \(450^{\circ} \mathrm{C}\) (a) What is the partial pressure of \(\mathrm{N}_{2} ?\) (b) If the gases occupy a volume of \(1.5 \mathrm{L}\), what mass of nitroglycerin was detonated?

\(\mathrm{Ni}(\mathrm{CO})_{4}\) can be made by reacting finely divided nickel with gaseous CO. If you have \(\mathrm{CO}\) in a 1.50-L flask at a pressure of \(418 \mathrm{mm}\) Hg at \(25.0^{\circ} \mathrm{C},\) along with \(0.450 \mathrm{g}\) of \(\mathrm{Ni}\) powder, what is the theoretical yield of \(\mathrm{Ni}(\mathrm{CO})_{4} ?\)

Ethane burns in air to give \(\mathrm{H}_{2} \mathrm{O}\) and \(\mathrm{CO}_{2}\) $$ 2 \mathrm{C}_{2} \mathrm{H}_{6}(\mathrm{g})+7 \mathrm{O}_{2}(\mathrm{g}) \rightarrow 4 \mathrm{CO}_{2}(\mathrm{g})+6 \mathrm{H}_{2} \mathrm{O}(\mathrm{g}) $$ (a) Four gases are involved in this reaction. Place them in order of increasing rms speed. (Assume all are at the same temperature.) (b) \(\mathrm{A} 3.26-\mathrm{L}\) flask contains \(\mathrm{C}_{2} \mathrm{H}_{6}\) at a pressure of \(256 \mathrm{mm}\) Hg and a temperature of \(25^{\circ} \mathrm{C}\) Suppose \(\mathrm{O}_{2}\) gas is added to the flask until \(\mathrm{C}_{2} \mathrm{H}_{6}\) and \(\mathrm{O}_{2}\) are in the correct stoichiometric ratio for the combustion reaction. At this point, what is the partial pressure of \(\mathbf{O}_{2}\) and what is the total pressure in the flask?

You have four gas samples: 1\. 1.0 L of \(\mathrm{H}_{2}\) at STP 2\. 1.0 L of Ar at STP 3\. \(1.0 \mathrm{L}\) of \(\mathrm{H}_{2}\) at \(27^{\circ} \mathrm{C}\) and \(760 \mathrm{mm} \mathrm{Hg}\) 4\. 1.0 L of He at \(0^{\circ} \mathrm{C}\) and \(900 \mathrm{mm} \mathrm{Hg}\) (a) Which sample has the largest number of gas particles (atoms or molecules)? (b) Which sample contains the smallest number of particles? (c) Which sample represents the largest mass?

Propane reacts with oxygen to give carbon dioxide and water vapor. $$ \mathrm{C}_{3} \mathrm{H}_{8}(\mathrm{g})+5 \mathrm{O}_{2}(\mathrm{g}) \rightarrow 3 \mathrm{CO}_{2}(\mathrm{g})+4 \mathrm{H}_{2} \mathrm{O}(\mathrm{g}) $$ If you mix \(\mathrm{C}_{3} \mathrm{H}_{8}\) and \(\mathrm{O}_{2}\) in the correct stoichiometric ratio, and if the total pressure of the mixture is \(288 \mathrm{mm} \mathrm{Hg}\), what are the partial pressures of \(\mathrm{C}_{3} \mathrm{H}_{8}\) and \(\mathrm{O}_{2} ?\) If the temperature and volume do not change, what is the pressure of the water vapor after reaction?

Iron carbonyl can be made by the direct reaction of iron metal and carbon monoxide. $$ \mathrm{Fe}(\mathrm{s})+5 \mathrm{CO}(\mathrm{g}) \rightarrow \mathrm{Fe}(\mathrm{CO})_{5}(\ell) $$ What is the theoretical yield of \(\mathrm{Fe}(\mathrm{CO})_{5}\) if \(3.52 \mathrm{g}\) of iron is treated with CO gas having a pressure of \(732 \mathrm{mm} \mathrm{Hg}\) in a \(5.50-\mathrm{L}\) flask at \(23^{\circ} \mathrm{C} ?\)

There are five compounds in the family of sulfurfluorine compounds with the general formula \(\mathrm{S}_{x} \mathrm{F}_{y}\). One of these compounds is \(25.23 \%\) S. If you place \(0.0955 \mathrm{g}\) of the compound in a \(89-\mathrm{mL}\) flask at \(45^{\circ} \mathrm{C},\) the pressure of the gas is \(83.8 \mathrm{mm} \mathrm{Hg}\). What is the molecular formula of \(\mathrm{S}_{x} \mathrm{F}_{y} ?\)

A miniature volcano can be made in the laboratory with ammonium dichromate. When ignited, it decomposes in a fiery display. $$ \left(\mathrm{NH}_{4}\right)_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}(\mathrm{s}) \rightarrow \mathrm{N}_{2}(\mathrm{g})+4 \mathrm{H}_{2} \mathrm{O}(\mathrm{g})+\mathrm{Cr}_{2} \mathrm{O}_{3}(\mathrm{s}) $$ If 0.95 g of ammonium dichromate is used and the gases from this reaction are trapped in a 15.0 -L flask at \(23^{\circ} \mathrm{C},\) what is the total pressure of the gas in the flask? What are the partial pressures of \(\mathrm{N}_{2}\) and \(\mathrm{H}_{2} \mathrm{O} ?\)

Chlorine dioxide, \(\mathrm{ClO}_{2}\), reacts with fluorine to give a new gas that contains \(\mathrm{Cl}, \mathrm{O},\) and \(\mathrm{F}\). In an experiment, you find that \(0.150 \mathrm{g}\) of this new gas has a pressure of \(17.2 \mathrm{mm}\) Hg in a 1850 -mL flask at \(21^{\circ} \mathrm{C} .\) What is the identity of the unknown gas?

A xenon fluoride can be prepared by heating a mixture of Xe and \(\mathrm{F}_{2}\) gases to a high temperature in a pressure-proof container. Assume that xenon gas was added to a 0.25-L container until its pressure reached 0.12 atm at \(0.0^{\circ}\) C. Fluorine gas was then added until the total pressure reached 0.72 atm at \(0.0^{\circ} \mathrm{C} .\) After the reaction was complete, the xenon was consumed completely, and the pressure of the \(\mathrm{F}_{2}\) remaining in the container was 0.36 atm at \(0.0^{\circ} \mathrm{C}\). What is the empirical formula of the xenon fluoride?

Several small molecules (besides water) are important in biochemical systems: \(\mathrm{O}_{2}, \mathrm{CO}, \mathrm{CO}_{2}\) and NO. You have isolated one of these and to identify it you determine its molar mass. You release 0.37 g of the gas into a flask with a volume of \(732 \mathrm{mL}\) at \(21^{\circ} \mathrm{C}\). The gas pressure in the flask is \(209 \mathrm{mm}\) Hg. What is the unknown gas?

Consider the following gases: \(\mathrm{He}, \mathrm{SO}_{2}, \mathrm{CO}_{2},\) and \(\mathrm{Cl}_{2}\) (a) Which has the largest density (assuming that all gases are at the same T and P)? (b) Which gas will effuse fastest through a porous plate?

Which of the following is not correct? (a) Diffusion of gases occurs more rapidly at higher temperatures. (b) Effusion of \(\mathrm{H}_{2}\) is faster than effusion of He (assume similar conditions and a rate expressed in units of mol/h). (c) Diffusion will occur faster at low pressure than at high pressure. (d) The rate of effusion of a gas (mol/h) is directly proportional to molar mass.

Carbon dioxide, \(\mathrm{CO}_{2}\), was shown to effuse through a porous plate at the rate of 0.033 mol/ min. The same quantity of an unknown gas, 0.033 moles, is found to effuse through the same porous barrier in 104 seconds. Calculate the molar mass of the unknown gas.

In an experiment, you have determined that 0.66 moles of \(\mathrm{CF}_{4}\) effuse through a porous barrier over a 4.8 -minute period. How long will it take for 0.66 moles of \(\mathrm{CH}_{4}\) to effuse through the same barrier?

A balloon is filled with helium gas to a gauge pressure of \(22 \mathrm{mm}\) Hg at \(25^{\circ} \mathrm{C}\). The volume of the gas is \(305 \mathrm{mL},\) and the barometric pressure is \(755 \mathrm{mm}\) Hg. What amount of helium is in the balloon? (Remember that gauge pressure = total pressure - barometric pressure. See page \(452 .\) )

You are given 1.56 g of a mixture of \(\mathrm{KClO}_{3}\) and KCl. When heated, the \(\mathrm{KClO}_{3}\) decomposes to KCl and \(\mathbf{O}_{2}\) $$ 2 \mathrm{KClO}_{3}(\mathrm{s}) \rightarrow 2 \mathrm{KCl}(\mathrm{s})+3 \mathrm{O}_{2}(\mathrm{g}) $$ and \(327 \mathrm{mL}\) of \(\mathrm{O}_{2}\) with a pressure of \(735 \mathrm{mm} \mathrm{Hg}\) is collected at \(19^{\circ} \mathrm{C}\). What is the weight percentage of \(\mathrm{KClO}_{3}\) in the sample?

A study of climbers who reached the summit of Mount Everest without supplemental oxygen showed that the partial pressures of \(\mathrm{O}_{2}\) and \(\mathrm{CO}_{2}\) in their lungs were \(35 \mathrm{mm}\) Hg and \(7.5 \mathrm{mm} \mathrm{Hg}\) respectively. The barometric pressure at the summit was \(253 \mathrm{mm}\) Hg. Assume the lung gases are saturated with moisture at a body temperature of \(37^{\circ} \mathrm{C}\) [which means the partial pressure of water vapor in the lungs is \(\left.P\left(\mathrm{H}_{2} \mathrm{O}\right)=47.1 \mathrm{mm} \mathrm{Hg}\right] .\) If you assume the lung gases consist of only \(\mathrm{O}_{2}, \mathrm{N}_{2}\) \(\mathrm{CO}_{2},\) and \(\mathrm{H}_{2} \mathrm{O},\) what is the partial pressure of \(\mathrm{N}_{2} ?\)

Nitrogen monoxide reacts with oxygen to give nitrogen dioxide: $$ 2 \mathrm{NO}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g}) \rightarrow 2 \mathrm{NO}_{2}(\mathrm{g}) $$ (a) Place the three gases in order of increasing rms speed at \(298 \mathrm{K}\) (b) If you mix \(\mathrm{NO}\) and \(\mathrm{O}_{2}\) in the correct stoichiometric ratio and NO has a partial pressure of \(150 \mathrm{mm} \mathrm{Hg},\) what is the partial pressure of \(\mathrm{O}_{2} ?\) (c) After reaction between \(\mathrm{NO}\) and \(\mathrm{O}_{2}\) is complete, what is the pressure of \(\mathrm{NO}_{2}\) if the NO originally had a pressure of \(150 \mathrm{mm} \mathrm{Hg}\) and \(\mathrm{O}_{2}\) was added in the correct stoichiometric amount?

Chlorine trifluoride, \(\mathrm{ClF}_{3,}\) is a valuable reagent because it can be used to convert metal oxides to metal fluorides: \(6 \mathrm{NiO}(\mathrm{s})+4 \mathrm{ClF}_{3}(\mathrm{g}) \rightarrow\) \(6 \mathrm{NiF}_{2}(\mathrm{s})+2 \mathrm{Cl}_{2}(\mathrm{g})+3 \mathrm{O}_{2}(\mathrm{g})\) (a) What mass of NiO will react with \(\mathrm{ClF}_{3}\) gas if the gas has a pressure of \(250 \mathrm{mm}\) Hg at \(20^{\circ} \mathrm{C}\) in a 2.5 -L flask? (b) If the \(\mathrm{ClF}_{3}\) described in part (a) is completely consumed, what are the partial pressures of \(\mathrm{Cl}_{2}\) and of \(\mathrm{O}_{2}\) in the 2.5 -L flask at \(20^{\circ} \mathrm{C}\) (in mm Hg)? What is the total pressure in the flask?

You have a \(550 .\) -mL tank of gas with a pressure of 1.56 atm at \(24^{\circ} \mathrm{C}\). You thought the gas was pure carbon monoxide gas, \(\mathrm{CO},\) but you later found it was contaminated by small quantities of gaseous \(\mathrm{CO}_{2}\) and \(\mathrm{O}_{2}\). Analysis shows that the tank pressure is 1.34 atm \(\left(\text { at } 24^{\circ} \mathrm{C}\right)\) if the \(\mathrm{CO}_{2}\) is removed. Another experiment shows that \(0.0870 \mathrm{g}\) of \(\mathrm{O}_{2}\) can be removed chemically. What are the masses of \(\mathrm{CO}\) and \(\mathrm{CO}_{2}\) in the tank, and what is the partial pressure of each of the three gases at \(25^{\circ} \mathrm{C} ?\)

Methane is burned in a laboratory Bunsen burner to give \(\mathrm{CO}_{2}\) and water vapor. Methane gas is supplied to the burner at the rate of \(5.0 \mathrm{L} / \mathrm{min}\) (at a temperature of \(28^{\circ} \mathrm{C}\) and a pressure of \(773 \mathrm{mm} \mathrm{Hg}\) ). At what rate must oxygen be supplied to the burner (at a pressure of \(742 \mathrm{mm} \mathrm{Hg}\) and a temperature of \(\left.26^{\circ} \mathrm{C}\right) ?\)

Iron forms a series of compounds of the type \(\mathrm{Fe}_{x}(\mathrm{CO})_{y}\). In air, these compounds are oxidized to \(\mathrm{Fe}_{2} \mathrm{O}_{3}\) and \(\mathrm{CO}_{2}\) gas. After heating a 0.142-g sample of \(\mathrm{Fe}_{x}(\mathrm{CO})_{y}\) in air, you isolate the \(\mathrm{CO}_{2}\) in a \(1.50-\mathrm{L}\) flask at \(25^{\circ} \mathrm{C}\). The pressure of the gas is \(44.9 \mathrm{mm}\) Hg. What is the empirical formula of \(\mathrm{Fe}_{x}(\mathrm{CO})_{y} ?\)

Group 2 A metal carbonates are decomposed to the metal oxide and \(\mathrm{CO}_{2}\) on heating: $$ \mathrm{MCO}_{3}(\mathrm{s}) \rightarrow \mathrm{MO}(\mathrm{s})+\mathrm{CO}_{2}(\mathrm{g}) $$ You heat 0.158 g of a white, solid carbonate of a Group \(2 \mathrm{A}\) metal \((\mathrm{M})\) and find that the evolved \(\mathrm{CO}_{2}\) has a pressure of \(69.8 \mathrm{mm}\) Hg in a \(285-\mathrm{mL}\) flask at \(25^{\circ} \mathrm{C} .\) Identify \(\mathrm{M}\).

One way to synthesize diborane, \(\mathrm{B}_{2} \mathrm{H}_{6}\), is the reaction \(\begin{aligned} 2 \mathrm{NaBH}_{4}(\mathrm{s})+2 \mathrm{H}_{3} \mathrm{PO}_{4}(\ell) & \rightarrow \\ \mathrm{B}_{2} \mathrm{H}_{6}(\mathrm{g})+& 2 \mathrm{NaH}_{2} \mathrm{PO}_{4}(\mathrm{s})+2 \mathrm{H}_{2}(\mathrm{g}) \end{aligned}\) (a) If you have \(0.136 \mathrm{g}\) of \(\mathrm{NaBH}_{4}\) and excess \(\mathrm{H}_{3} \mathrm{PO}_{4},\) and you collect the resulting \(\mathrm{B}_{2} \mathrm{H}_{6}\) in a 2.75 -L flask at \(25^{\circ} \mathrm{C},\) what is the pressure of the \(\mathrm{B}_{2} \mathrm{H}_{6}\) in the flask? (b) A by-product of the reaction is \(\mathrm{H}_{2}\) gas. If both \(\mathrm{B}_{2} \mathrm{H}_{6}\) and \(\mathrm{H}_{2}\) gas come from this reaction, what is the total pressure in the \(2.75-\mathrm{L}\) flask (after reaction of 0.136 g of NaBH_with excess \(\left.\mathrm{H}_{3} \mathrm{PO}_{4}\right)\) at \(25^{\circ} \mathrm{C} ?\)

You are given a solid mixture of \(\mathrm{NaNO}_{2}\) and \(\mathrm{NaCl}\) and are asked to analyze it for the amount of NaNO_ present. To do so, you allow the mixture to react with sulfamic acid, \(\mathrm{HSO}_{3} \mathrm{NH}_{2}\), in water according to the equation \(\begin{aligned} \operatorname{NaNO}_{2}(\mathrm{aq})+\mathrm{HSO}_{3} \mathrm{NH}_{2}(\mathrm{aq}) \rightarrow & \\ \mathrm{NaHSO}_{4}(\mathrm{aq}) &+\mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{N}_{2}(\mathrm{g}) \end{aligned}\) What is the weight percentage of \(\mathrm{NaNO}_{2}\) in \(1.232 \mathrm{g}\) of the solid mixture if reaction with sulfamic acid produces \(295 \mathrm{mL}\) of dry \(\mathrm{N}_{2}\) gas with a pressure of \(713 \mathrm{mm}\) Hg at \(21.0^{\circ} \mathrm{C} ?\)

A compound containing \(\mathrm{C}, \mathrm{H}, \mathrm{N},\) and \(\mathrm{O}\) is burned in excess oxygen. The gases produced by burning 0.1152 g are first treated to convert the nitrogen-containing product gases into \(\mathrm{N}_{2}\), and then the resulting mixture of \(\mathrm{CO}_{2}, \mathrm{H}_{2} \mathrm{O}, \mathrm{N}_{2},\) and excess \(\mathrm{O}_{2}\) is passed through a bed of \(\mathrm{CaCl}_{2}\) to absorb the water. The \(\mathrm{CaCl}_{2}\) increases in mass by \(0.09912 \mathrm{g} .\) The remaining gases are bubbled into water to form \(\mathrm{H}_{2} \mathrm{CO}_{3}\), and this solution is titrated with \(0.3283 \mathrm{M} \mathrm{NaOH} ; 28.81 \mathrm{mL}\) is required to achieve the second equivalence point. The excess \(\mathrm{O}_{2}\) gas is removed by reaction with copper metal (to give CuO). Finally, the \(\mathrm{N}_{2}\) gas is collected in a 225.0 -mL flask, where it has a pressure of \(65.12 \mathrm{mm} \mathrm{Hg}\) at \(25^{\circ} \mathrm{C} .\) In a separate experiment, the unknown compound is found to have a molar mass of \(150 \mathrm{g} / \mathrm{mol} .\) What are the empirical and molecular formulas of the unknown compound?

You have a gas, one of the three known phosphorus-fluorine compounds \(\left(\mathrm{PF}_{3}, \mathrm{PF}_{5},\right.\) and \(\mathrm{P}_{2} \mathrm{F}_{4}\) ). To find out which, you have decided to measure its molar mass. (a) First, you determine that the density of the gas is \(5.60 \mathrm{g} / \mathrm{L}\) at a pressure of 0.971 atm and a temperature of \(18.2^{\circ} \mathrm{C} .\) Calculate the molar mass and identify the compound. (b) To check the results from part (a), you decide to measure the molar mass based on the relative rates of effusion of the unknown gas and \(\mathrm{CO}_{2} .\) You find that \(\mathrm{CO}_{2}\) effuses at a rate of \(0.050 \mathrm{mol} / \mathrm{min},\) whereas the unknown phosphorus fluoride effuses at a rate of 0.028 mol/ min. Calculate the molar mass of the unknown gas based on these results.

A 1.0 -L flask contains 10.0 g each of \(\mathrm{O}_{2}\) and \(\mathrm{CO}_{2}\) at \(25^{\circ} \mathrm{C}\) (a) Which gas has the greater partial pressure, \(\mathrm{O}_{2}\) or \(\mathrm{CO}_{2}\), or are they the same? (b) Which molecules have the greater rms speed, or are they the same? (c) Which molecules have the greater average kinetic energy, or are they the same?

If equal masses of \(\mathrm{O}_{2}\) and \(\mathrm{N}_{2}\) are placed in separate containers of equal volume at the same temperature, which of the following statements is true? If false, explain why it is false. (a) The pressure in the flask containing \(\mathrm{N}_{2}\) is greater than that in the flask containing \(\mathrm{O}_{2}\) (b) There are more molecules in the flask containing \(\mathrm{O}_{2}\) than in the flask containing \(\mathrm{N}_{2}\).

You have two pressure-proof steel cylinders of equal volume, one containing \(1.0 \mathrm{kg}\) of \(\mathrm{CO}\) and the other containing \(1.0 \mathrm{kg}\) of acetylene, \(\mathrm{C}_{2} \mathrm{H}_{2}\) (a) In which cylinder is the pressure greater at \(25^{\circ} \mathrm{C}\) (b) Which cylinder contains the greater number of molecules?

Two flasks, each with a volume of \(1.00 \mathrm{L},\) contain \(\mathrm{O}_{2}\) gas with a pressure of \(380 \mathrm{mm}\) Hg. Flask \(\mathrm{A}\) is at \(25^{\circ} \mathrm{C},\) and flask \(\mathrm{B}\) is at \(0^{\circ} \mathrm{C}\). Which flask contains the greater number of \(\mathrm{O}_{2}\) molecules?

A State whether each of the following samples of matter is a gas. If there is not enough information for you to decide, write "insufficient information." (a) A material is in a steel tank at 100 atm pressure. When the tank is opened to the atmosphere, the material suddenly expands, increasing its volume by \(1 \% .\) (b) A 1.0 -mL sample of material weighs \(8.2 \mathrm{g}\). (c) The material is transparent and pale green in color. (d) One cubic meter of material contains as many molecules as \(1.0 \mathrm{m}^{3}\) of air at the same temperature and pressure.

You have two gas-filled balloons, one containing He and the other containing \(\mathrm{H}_{2} .\) The \(\mathrm{H}_{2}\) balloon is twice the volume of the He balloon. The pressure of gas in the \(\mathrm{H}_{2}\) balloon is 1 atm, and that in the He balloon is 2 atm. The \(H_{2}\) balloon is outside in the snow \(\left(-5^{\circ} \mathrm{C}\right),\) and the He balloon is inside a warm building \(\left(23^{\circ} \mathrm{C}\right) .\) (a) Which balloon contains the greater number of molecules? (b) Which balloon contains the greater mass of gas?

The sodium azide required for automobile air bags is made by the reaction of sodium metal with dinitrogen monoxide in liquid ammonia: \(3 \mathrm{N}_{2} \mathrm{O}(\mathrm{g})+4 \mathrm{Na}(\mathrm{s})+\mathrm{NH}_{3}(\ell) \rightarrow\) $$ \mathrm{NaN}_{3}(\mathrm{s})+3 \mathrm{NaOH}(\mathrm{s})+2 \mathrm{N}_{2}(\mathrm{g}) $$ (a) You have \(65.0 \mathrm{g}\) of sodium, a 35.0 -L flask containing \(\mathrm{N}_{2} \mathrm{O}\) gas with a pressure of 2.12 atm at \(23^{\circ} \mathrm{C},\) and excess ammonia. What is the theoretical yield (in grams) of \(\mathrm{NaN}_{3} ?\) (b) Draw a Lewis structure for the azide ion. Include all possible resonance structures. Which resonance structure is most likely? (c) What is the shape of the azide ion?

If the absolute temperature of a gas doubles, by how much does the rms speed of the gaseous molecules increase?

A Chlorine gas \(\left(\mathrm{Cl}_{2}\right)\) is used as a disinfectant in municipal water supplies, although chlorine dioxide \(\left(\mathrm{ClO}_{2}\right)\) and ozone are becoming more widely used. \(\mathrm{ClO}_{2}\) is a better choice than \(\mathrm{Cl}_{2}\) in this application because it leads to fewer chlorinated by-products, which are themselves pollutants. (a) How many valence electrons are in \(\mathrm{ClO}_{2} ?\) (b) The chlorite ion, \(\mathrm{ClO}_{2}^{-},\) is obtained by reducing \(\mathrm{ClO}_{2}\). Draw a possible electron dot structure for \(\mathrm{ClO}_{2}^{-} .\) (Cl is the central atom.) (c) What is the hybridization of the central Cl atom in \(\mathrm{ClO}_{2}^{-}\) ? What is the shape of the ion? (d) Which species has the larger bond angle, \(\mathrm{O}_{3}\) or \(\mathrm{ClO}_{2}^{-} ?\) Explain briefly. (e) Chlorine dioxide, \(\mathrm{ClO}_{2},\) a yellow-green gas, can be made by the reaction of chlorine with sodium chlorite: $$2 \mathrm{NaClO}_{2}(\mathrm{s})+\mathrm{Cl}_{2}(\mathrm{g}) \rightarrow 2 \mathrm{NaCl}(\mathrm{s})+2 \mathrm{ClO}_{2}(\mathrm{g})$$ Assume you react \(15.6 \mathrm{g}\) of \(\mathrm{NaClO}_{2}\) with chlorine gas, which has a pressure of \(1050 \mathrm{mm} \mathrm{Hg}\) in a 1.45-L flask at \(22^{\circ} \mathrm{C}\). What mass of \(\mathrm{ClO}_{2}\) can be produced?