# Lycoming College                                          Quiz 6                                                  Write name on back

Chem 110, 2002                                                                                                         upper right

Useful information:  PV = nRT       R = 0.08206 L.atm.K-1mol-1         1 atm = 760 Torr (or mmHg)              K = °C + 273.15

1.   A balloon is filled with helium.  Its volume is 4.83 L at 24 °C.  What will be its volume at  –195 °C if the pressure remains constant?

This problem exemplifies the gas law named after _____________________.

2.   In the chemical reaction used in the automotive air bag safety systems, N2(g) is produced by the decomposition of sodium azide, NaN3:

2 NaN3(s)      ®      2 Na      +      3 N2(g)

a.       If you decomposed 50.0 g of NaN3 (F.W.=65.01), how many moles of N2(g) would be formed?

b.       Based on your answer to 2a, what volume (in L) would this N2(g) occupy at a pressure of 767 Torr

and a temperature of 24°C?

3.   Calculate the molar mass of a gas if 0.440 g occupies 179 mL at 86°C and 741 Torr.

4.   Hydrogen is collected over water at 18 °C.  The total pressure in the collection flask is adjusted to the barometric pressure of 738 Torr.  At 18°C, water vapor pressure is 15.5 mmHg.  Calculate the partial pressure of the hydrogen.