Which statement is true of a chemical change?
OA.
It involves changes in the molecular structure.
OB.
It involves changes in phase but not changes in the molecular structure.
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C.
It involves dissolving one substance into another.
OD.
It involves a change in the state, or phase, of a substance.
E.
It involves the process of separating two or more dissolved substances.

The covalent compound acetylene, which is the fuel of the oxyacetylene torch used by welders, has the molecular formula c2h2. the covalent compound benzene, a commercial solvent, has the molecular formula c6h6 each of these covalent compounds contains carbon and hydrogen atoms in a one-to-one ratio. would it be correct to write the chemical formulas of each as ch? explain.