|  |  |  |  |  |  |  |  |  |  | 
   
    | • | The
    partial pressure of CH4(g) is 0.225atm 
 |  | 
   
    |  |  | 
   
    |  | and C2H6(g)
    is 0.165 atm in a  mixture of 
 |  | 
   
    |  | the two gases.
    What is the total pressure? 
 |  | 
   
    |  | 
   
    | • | A gas
    mixture has three components, N2, O2 
 | 
   
    |  | 
   
    |  | and He. If the
    total pressure of the mixture 
 |  | 
   
    |  | 
   
    |  | is 0.78 atm and
    the partial pressure of N2 
 |  | 
   
    |  | 
   
    |  | and He are 0.40
    atm and 0. 18 atm 
 |  | 
   
    |  | 
   
    |  | respectively,
    what is the partial pressure of 
 |  | 
   
    |  | 
   
    |  | the O2
    in the mixture? 
 |  |