The first one is substance 3
The second one is Oxygen, Helium, and carbon dioxide
The third one is the oil floats on top of the water
        
                    
             
        
        
        
Why does the volcano cause an explosion?
        
             
        
        
        
The negative ion reactions that consist of the formation of carbon dioxide in the atmosphere is generally an exothermic reaction. By definition, an exothermic reaction takes place when the chemical process eventually releases heat as its by-product. It is in contrast in endothermic process wherein heat is absorbed.
        
                    
             
        
        
        
Answer:
4.81 moles
Explanation:
The total pressure of the gas = Pressure at which gauge reads zero + pressure read by it.
Pressure at which gauge reads zero = 14.7 psi
Pressure read by the gauge = 988 psi
Total pressure = 14.7 + 988 psi = 1002.7 psi
Also, P (psi) = P (atm) / 14.696
Pressure = 1002.7 / 14.696  = 68.2297 atm
Temperature = 25 °C
The conversion of T( °C) to T(K) is shown below:
T(K) = T( °C) + 273.15  
So,  
T = (25 + 273.15) K = 298.15 K  
Volume = 1.50 L 
Using ideal gas equation as:
PV=nRT
where,  
P is the pressure
V is the volume
n is the number of moles
T is the temperature  
R is Gas constant having value = 0.0821 L.atm/K.mol
Applying the equation as:
68.2297 atm × 1.5 L = n × 0.0821 L.atm/K.mol × 298.15 K  
⇒n = 4.81 moles