The correct answer that would best complete the given statement above would be the word MIXTURE. <span>A substance which contains various elements or compounds without bonding or in fixed proportions is a mixture. When a chemical union occurs, this is when a compound is being formed. Hope this answer helps.</span>
        
             
        
        
        
The chemical bonds in CH4 are all single bonds. C only can bond 4 times because it needs 8 electrons in it's outer shell and only has four right now. The bonds represented are all single bonds because there are two electrons present on each side of the carbon. Two electrons, in this case, equals one bond.
        
             
        
        
        
The heat required to vaporize 43.9 g  of acetone  at its boiling point is calculated as  below
 the heat of vaporization of acetone at its boiling  point is  29.1 kj/mole
find the moles of  acetone = mass/molar mass
= 43.9g /58 g/mol =0.757 moles
heat (Q) = moles x heat of vaporization
= 29.1 kj/mole  x 0.757 moles = 22.03 kj