Answer: A.  Exothermic reaction
Explanation: Enthalpy change for a reaction is sum of enthalpy of formation of products minus sum of enthalpy of formation of reactants. 
When the energy level of reactants is above as compared to the products, the reaction is exothermic and when its opposite then reaction is endothermic.
From given information, the potential energy diagram starts at 380 kJ means the energy level of reactants is 380 kJ. It ends at 100 kJ means the energy of products is 100 kJ.
Enthalpy of reaction = 100 kJ - 380 kJ
Enthalpy of reaction = -280 kJ
Negative sign of enthalpy change indicates an Exothermic reaction. 
 
        
                    
             
        
        
        
The atomic mass of the element would simply be equal to
the sum of the weighted average of each isotope, that is:
atomic mass = 59.015 amu * 0.717 + 62.011 amu * (1 – 0.717)
<span>atomic mass = 59.863 amu</span>
 
        
             
        
        
        
Answer:
D
Explanation:
∆H° = ∆Hf ° (products) – ∆Hf ° (reactants)
 
        
             
        
        
        
C plasmas have a net negative charge
        
                    
             
        
        
        
Answer:
Exergonic ,Endergonic,low concentration area,high
Explanation:
In exergonic reaction,certain molecules are broken down;in the process they release energy which is captured when high energy molecules(such as ATP and NADH) are formed.
                           The breakdown of these molecules can be coupled to thermodynamically unfavorable processes such as Endergonic reactions or pumping og hydrogen ion from low concentration areas to high concentration areas.