The answer is B. This is because Sodium has 1 valence electron and Fluorine has 7 valence electrons. All elements want 8 valence electrons so they may be stale, like the noble gases are. Hope this helps.
Answer: A. To change the potential energy of the reactants.
Explanation:
Catalysts make such a breaking and rebuilding happen more efficiently. They do this by lowering the activation energy for the chemical reaction. Activation energy is the amount of energy needed to allow the chemical reaction to occur. The catalyst just changes the path to the new chemical partnership.
Answer:
a) 
b) 
d) 
d) 
Explanation:
From the question we are told that:
Moles of N2 
Atmospheric pressure 
Temperature 

Initial heat 
a)
Generally the equation for change in temperature is mathematically given by

Where




b)
Generally the equation for ideal gas is mathematically given by

For v double


Therefore



Total Work-done 



c)
Generally the equation for amount of heat added is mathematically given by



d)
Generally the equation for change in internal energy of the gas is mathematically given by


