M= 1 and n = 2
( m+ n =  1 +2  = 3)
rate = K [A] [B]^2
0.2  = K *  3  * 3 ^2
0.2 =  K  *  3 * 9 
 K =    0.2   / 27 
K =   7.408 *  10 ^ -3  m^-2  s^-1
        
                    
             
        
        
        
Answer:
2) Copper (II) Chloride
Explanation:
A precipitate will form if the resulting compound is insoluble in water. For example, a silver nitrate solution (AgNO3) is mixed with a solution of magnesium bromide (MgBr2).
 
        
             
        
        
        
Answer:
X 154
Check solution in explanation
Explanation:
Average atomic mass = ( mass 1× abudance) + ( mass 2× abudance)+ ( mass 3× abudance) / 100
(149×13.8)+(152×44.9) +(154×41.3)/100
2056.2 + 6824.8 + 6360.2/100
=152.412
 
        
             
        
        
        
Solar Energy is the answer