I believe the answer is A
        
                    
             
        
        
        
Answer:
Chemical energy, Energy stored in the bonds of chemical compounds. Chemical energy may be released during a chemical reaction, often in the form of heat; such reactions are called exothermic.
 
        
             
        
        
        
Answer:

Explanation:
First of all let's define the specific molar heat capacity.
 (1)
 (1)
Where:
Q is the released heat by the system
n is the number of moles
ΔT is the difference of temperature of the system  
Now, we can find n with the molar mass (M) the mass of the compound (m).
 
       
Using (1) we have:


I hope it helps!
 
        
             
        
        
        
Answer each friend will get 3.33333 repeating if he is included. if only his friends are getting them then each one gets 4
Explanation:
devide 20/6 and 20/5 respectively. 
 
        
             
        
        
        
Answer:
At the end points of motion (either side) the velocity must be zero because the velocity is changing from - to + (it can't turn around around without passing thru zero,
The velocity will then increase to the midpoint of the motion.
m g h = 1/2 m v^2    where h is the vertical distance thru which the pendulum travels