Answer:
It's the second one down.
Explanation:
Gold
Mass 197
Number of Protons: 79
Number of Neutrons: 197 - 79 = 118
Number of electrons: = number of protons = 97
 
        
             
        
        
        
B will be the one I think tbh
        
             
        
        
        
Answer:
The answer to your question is:  69.6 %
Explanation:
Freon -112 (C₂Cl₄F₂)
MW = (12 x 2) + (35.5 x 4) + (19 x 2)
       = 24 + 142 + 38
       = 204 g
                        204 g of C₂Cl₄F₂  -----------------  100%
                        142 g                     -----------------   x
                       x = (142 x 100 ) / 204
                       x = 69.6 %
 
        
                    
             
        
        
        
Its running pressure in torr would be :
5.10 x 10^8 pa  x 1kPa/1000 Pa x 760 / 101.325 kPa
= 5.10 x 10 ^5  x   76 x 10^-1  x 1.01325 x 10 ^-2
= 392.7375 x 10^2
= 3.927275 x 10^4
ope this helps