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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c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

answer: e.   sour taste

explanation: acids are those substances which dissociates in water to give ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. acids are sour in taste. example: hcl

bases are those substances which dissociates in water to give ions or accepts ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. bases are bitter in taste. bases are slippery in nature.