1)      An average pair of human lungs contains about 3.5 L of air after inhalation and about 3.0 L after exhalation.  Assuming that the air in your lungs is at 37^oC and 1.0 atm, determine the number of moles of air in a typical breath.  

2)      The boron hydride B₂H₆ burns in oxygen.

B₂H₆(g) + O₂(g)    B₂O₃(s) + 3H₂O(g)

If the reactant gases were mixed in the correct stoichiometric ratio and placed in a flask at 25^oC so the total pressure was 10 mmHg, what were the partial pressures of B₂H₆ and oxygen before the combustion?

3)      Lithium hydroxide is used in spacecraft to recondition the air by absorbing the carbon dioxide exhaled by astronauts.  The reaction is:

2 LiOH(s) + CO₂(g)  →  Li₂CO₃(s) + H₂O(l)

What volume of carbon dioxide gas at 21^oC and 781 mmHg could be absorbed by 348 grams of lithium hydroxide?  

4)      If 456 dm³ of krypton at 101 kPa and 21^oC is compressed into a 25 dm³ at the same temperature, what is the pressure in the tank?  

 5)      Butane is an easily liquefied gaseous fuel.  Calculate the density of butane gas in grams per liter at 0.897 atm and 23^oC.   

6)      A 200.0 mL flask contains 1.03 mg of O₂ and 0.41 mg of He at 15^oC.  Calculate the partial pressures of each gas within the flask.  What is the total pressure?

7)      Equal masses of gaseous N₂ and Ar are placed in separate flasks of equal volume, both gases being at the same temperature.  Tell whether each of the following statements is true or false, and explain your answer in each case.

a.      The pressure is greater in the Ar flask.

b.      Ar atoms have a greater speed compared to the N₂ molecules.

c.      The molecules of N₂ collide more frequently with the walls of the flask than do the atoms of Ar.