Base is Ca(OH)2.
Acid is H3PO4.
First part of the salt comes from base, 
second par comes from the acid.
        
             
        
        
        
Charles law gives the relationship between volume and temperature of gas.
It states that at constant pressure volume is directly proportional to temperature 
Therefore 
V/ T = k
Where V - volume T - temperature in kelvin and k - constant 
V1/T1 = V2/T2
Parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation 
Substituting the values in the equation
267 L/ 480 K = V / 750 K
V = 417 L
Final volume is 417 L
        
             
        
        
        
5 Valence electrons .......... Hope it helps, Have a nice day:)
        
                    
             
        
        
        
<span>V equals one-third times pi times r squared times h</span>