Explanation:
The given data is as follows.
       Pressure (P) = 760 torr = 1 atm
       Volume (V) =  = 0.720 L
 = 0.720 L
      Temperature (T) =  = (25 + 273) K = 298 K
 = (25 + 273) K = 298 K
Using ideal gas equation, we will calculate the number of moles as follows.
                                 PV = nRT
    Total atoms present (n) =  
                                           =  
                                            = 0.0294 mol
Let us assume that there are x mol of Ar and y mol of Xe.
Hence, total number of moles will be as follows.
                x + y = 0.0294 
Also,      40x + 131y = 2.966
              x = 0.0097 mol
               y = (0.0294 - 0.0097) 
                 = 0.0197 mol
Therefore, mole fraction will be calculated as follows.
Mol fraction of Xe =  
                                = 
                               = 0.67
Therefore, the mole fraction of Xe is 0.67.
 
        
             
        
        
        
Answer:
D
Explanation:
gas are well separated with no regular arrangement and spreaded all over. liquid are close together with no regular arrangement and slightly spreaded. solid are tightly packed, usually in a regular pattern and not spreaded at all.
 
        
                    
             
        
        
        
Any given experiment has numerous control variables, and it's important for a scientist to try to hold all variables constant except for the independent variable. If a control variable changes during an experiment, it may invalidate the correlation between the dependent and independent variables.
It’s copied and pasted from google so make sure to put it in your words :)
 
        
        
        
This is the Lewis Dot structure for oxygen