Bromine (Br) is the only element listed that is a diatomic element. I believe that Bromine is going to be your answer.
        
                    
             
        
        
        
Answer:
13500 N
Explanation:
According to newtons second law of motion
mass m =1500 Kg
a = 9m/s^2
Force F = mass m × acceleration a
F = 1500×9= 13500 N
 
        
             
        
        
        
Answer:
It's well Explained below. 
Explanation:
First of Excess product of CaCO_3 would be produced due to the fact that there would not be enough CaCl_2 to react with Na_2•CO_3. The main purpose of having stoichiometric quantities is for us to know the correct amount or near the correct amount of each reactant in order to create a product that will be close to the theoretical amount and thus have a higher percent yield.
 
        
             
        
        
        
I think the answer is ( A and C ) why I picked a and c it’s because a and c look the same answer. I hope it helped you