Most elements on group 18 are the Noble Gases. They already have a complete last level with 8 electrones. Actually they can form compounds but only on the lab and they will not even last half a second.
Chemical bonds is the answer
Answer : The internal energy change is, -506.3 kJ/mol
Explanation :
Formula used :
or,
where,
= change in enthalpy = 
= change in internal energy = ?
= change in moles
Change in moles = Number of moles of product side - Number of moles of reactant side
According to the reaction:
Change in moles = 0 - 2 = -2 mole
That means, value of 
= 0
R = gas constant = 8.314 J/mol.K
T = temperature = 
Now put all the given values in the above formula, we get
Therefore, the internal energy change is -506.3 kJ/mol
The answer to your question is D. hope this helps
-dabs-
Answer:
Nearly all of the water astronauts drink and shower with comes from their urine and sweat. Storage is hard to come by aboard the International Space Station. Even if a rocket had room to ferry thousands of pounds of water and oxygen to supply a six-month mission, you'd struggle to find anywhere to stash it.
Explanation:
