Which formula represents a nonpolar molecule containing polar covalent bonds?

The formula that represents  a nonpolar molecule containing polar covalent bonds is O=C=O.

A bond is polar when there is a high difference in electronegativity between the atoms in the bond. Carbon and oxygen form polar bonds because of the significant electronegativity difference between the two atoms.

However, the polarity of individual bonds does not mean that the molecule will be polar because dipole moment is a vector quantity. The direction of the dipole moment is also important.

In O=C=O, the dipoles are oriented in opposite directions therefore, they cancel out and the molecule is nonpolar even though it contains polar bonds.

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answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

there is none because earth is stationary and flat.