Epsilon-delta would be the green letter that is used in the precision definition of a limit. (ε, δ). 
        
             
        
        
        
A) C2H6O1
 
To find the emperical formula, divide each mole value by the smallest
For carbon, 0.013/0.0065 = 2
For hydrogen, 0.038/0.0065= 6
For oxygen, 0.0065/0.0065= 1
Emperical formula = C2H6O1
 
        
                    
             
        
        
        
I think it’s 2.45, not 100% sure
        
             
        
        
        
Answer : The fuel value and the fuel density of pentane is, 49.09 kJ/g and  respectively.
 respectively.
Explanation :
Fuel value : It is defined as the amount of energy released from the combustion of hydrocarbon fuels. The fuel value always in positive and in kilojoule per gram (kJ/g).
As we are given that:

Fuel value = 
Molar mass of pentane = 72 g/mol
Fuel value = 
Fuel value = 49.09 kJ/g
Now we have to calculate the fuel density of pentane.
Fuel density = Fuel value × Density
Fuel density = (49.09 kJ/g) × (0.626g/mL)
Fuel density = 30.73 kJ/mL = 
Thus, the fuel density of pentane is 