If a metal is bonded to carbon, they form ionic bonds. If a nonmetal forms a bond with carbon, they form covalent bond. Ionic bond requires metals to give away electrons to form cations and nonmetal to gain/accept electron to form anions. Covalent bond requires sharing of electrons between both elements. So if you meant exchange as in covalent bond, then no. Not many nonmetal elements form bonds with carbon as there are more metal elements in the periodic table.
a. 35.8 KJ
b. 871 g
c. Fe
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The mass of magnesium should be less than 0.09g to enable a faster reaction rate. Magnesium reacts to form a white coating around it which stops the reaction. The lesser the gram the faster the reaction before the coating is formed. It is also advisable to use magnesium fillings to increase the rate of reaction.