Question 1

Which of the following statements best describes a nonpolar molecule?

Accepted Answer

A molecule with a perfect shape and an even distribution of electrons.

Question 2

Carbon dioxide ($$\mathrm{CO_2$}) is $$classified as:

Accepted Answer

A nonpolar molecule because it has a perfect linear shape and the dipoles cancel.

Question 3

Which of the following compounds is polar due to its molecular shape?

Accepted Answer

Phosphorus trihydride ($$\mathrm{PH_3$})$$

Question 4

A molecule has a central atom with two bonds and two lone pairs. According to the molecular polarity chart, what is the polarity of this molecule?

Accepted Answer

Polar, because the shape is bent and the dipoles do not cancel.

Question 5

Which of the following best explains why $$\mathrm{BF_3$} is $$nonpolar?

Accepted Answer

It has a trigonal planar shape and the bond dipoles cancel out.

Question 6

Fluorine selenide ($$\mathrm{F_2Se}) is $$polar because:

Accepted Answer

It has lone pairs on the central atom, resulting in a bent shape.

Question 7

Which of the following molecules would be expected to be nonpolar based on its Lewis dot structure and shape?

Accepted Answer

Carbon dioxide ($$\mathrm{CO_2$})$$

Question 8

Which factor is most important in determining whether a molecule is polar or nonpolar?

Accepted Answer

The shape of the molecule and the distribution of electron density.

Question 9

A molecule with three bonds and one lone pair on the central atom will most likely be:

Accepted Answer

Polar, because the lone pair creates an asymmetrical shape.

Question 10

Which of the following is a correct statement about perfect shapes in molecular polarity?

Accepted Answer

Perfect shapes can result in nonpolar molecules if the bond dipoles cancel.

Question 11

If a molecule has a central atom with four bonds and no lone pairs, what is its expected polarity?

Accepted Answer

Nonpolar, because it has a perfect tetrahedral shape and the dipoles cancel.

Question 12

Which of the following molecules is polar due to the presence of lone pairs on the central atom?

Accepted Answer

Water ($$\mathrm{H_2O})$$

Question 13

Which of the following is NOT a reason a molecule might be polar?

Accepted Answer

It has a perfect shape and all bonds are identical.

Question 14

A student claims that all molecules with polar bonds are polar. Which molecule disproves this claim?

Accepted Answer

Carbon dioxide ($$\mathrm{CO_2$})$$

Question 15

Which of the following best describes the relationship between lone pairs and molecular polarity?

Accepted Answer

Lone pairs on the central atom often create an asymmetrical shape, leading to polarity.

Question 16

Which molecule would you expect to be polar based on its Lewis structure and shape?

Accepted Answer

Phosphorus trihydride ($$\mathrm{PH_3$})$$

Question 17

A molecule has a central atom with three bonds and no lone pairs. What is its expected shape and polarity?

Accepted Answer

Trigonal planar and nonpolar if the bonds are identical.

Question 18

Which of the following is a real-world example of a nonpolar molecule with polar bonds?

Accepted Answer

Carbon dioxide ($$\mathrm{CO_2$})$$

Question 19

Which of the following molecules is polar due to its bent shape?

Accepted Answer

Water ($$\mathrm{H_2O})$$

Question 20

Which of the following is the best method to determine if a molecule is polar or nonpolar?

Accepted Answer

Draw the Lewis dot structure, determine the shape, and check if the dipoles cancel.

Molecular Polarity and Perfect Shapes: Study Notes

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