Ch. 13  gas                               test [65 points]                                                Chem

Show your work in an organized manner, include (i) any relevant equation (or formula), (ii) conversion factor(s), (iii) put the proper units in your calculations and answer, and (iv) have the proper number of significant figures in your answer. 

1.  fill-in the blank.  [15 points]

a. 1.5 atm  =  ___ kPa

b.  755 torr  =  ____  atm

c. 125 kPa  =  ___  mm Hg

2. A 65.0 mL syringe has a pressure of 95.0 kPa and the room temperature is 21.0 ºC.  The syringe’s volume was reduced to 35.0 mL; what is the pressure in the syringe ?  [10 points]

3. A 65.0 mL syringe has a pressure of 95.0 kPa and the room temperature is 21.0 ºC.  The syringe’s volume was reduced to 25.0 mL and it was put into a freezer at -5.0 ºC; what is the pressure in the syringe ?   [10 points]

4.  At STP, 2.0 L N2 reacts with 5.0 L H2 to form ___ L NH3.  [15 points]

5. A 5.0 L container has 4.0 g hydrogen gas, 10.0 g helium gas, and 42.0 g nitrogen gas.  The temperature in the container is 37.0 ºC.    [15 points]

a.  What is the total pressure ?

b. What is the partial pressure of nitrogen ?

c. What is the mole fraction of helium ?