O2 is an example of a molecule
        
             
        
        
        
You’re correct, matter is made up of heat energy and chemical energy
all matter contains heat because it is the result of the movement of atoms, molecules, or ions in solids, liquids, and gases. 
all matter also contains chemical energy. chemical energy is stored in the bonds of chemical compounds so atoms and molecules are held together by chemical energy
hope this helps :)
        
             
        
        
        
Mg + 2H(NO)3 ⇒ Mg(NO3)2 + H2
        
             
        
        
        
Answer: The space occupied by the gas at 400 torr and 
 is 250 mL.
Explanation:
Given: 
 = 250 mL,    
 = 800 torr,     
,         
 = 400 torr,        
Formula used is as follows.

Substitute the values into above formula as follows.

Thus, we can conclude that space occupied by the gas at 400 torr and 
 is 250 mL.
 
        
             
        
        
        
The correct answer is D. The solute in this solution is the solid sodium nitrate (NaNO3) which is dissolved in the solvent, the water. Solute is the minor component in a solution whereas the solvent is the major component in the solution.