The overall asymmetric distribution of electric charge in a molecule, arising from the combination of individual bond polarities and the three-dimensional molecular geometry.
Even if individual bonds are polar, the molecule can be nonpolar if the dipoles cancel out symmetrically.
Showing a random 20 of 50 problems.
Example 1
hard
BF3 (planar, 0 D) reacts with NH3 (pyramidal, 1.47 D) to form H3N−BF3. Why is the adduct polar?
Example 2
easy
What does a molecular dipole moment of zero indicate about a molecule's polarity?
Example 3
challenge
Predict the polarity ordering of para-, meta-, and ortho-dichlorobenzene.
Example 4
medium
Which polar molecule has hydrogen bonding: NH3 or PH3?
Example 5
easy
The SI unit of dipole moment is the ____.
Example 6
hard
XeF2 is linear with three lone pairs on Xe. Polar or nonpolar?
Example 7
easy
Which molecule has the larger dipole moment: H2O (1.85 D) or H2S (0.97 D)?
Example 8
medium
BF3 is trigonal planar with three polar B-F bonds. Is it polar or nonpolar?
Example 9
medium
The dipole moment is μ=q×d. If q=1.6×10−19 C and d=1.0×10−10 m, find μ.
Example 10
hard
If a tetrahedral molecule AX4 has two X atoms replaced by Y (so AX2Y2, e.g., CH2Cl2), is it always polar?
Example 11
challenge
Why is cis-2-butene only weakly polar (~0.3 D) even though it lacks the symmetry of trans-2-butene?
Example 12
easy
Is SF6 (octahedral, six identical S-F bonds) polar or nonpolar?
Example 13
hard
Predict whether ozone O3 (bent) has a dipole moment despite all atoms being oxygen.
Example 14
easy
A molecule is polar overall only when its bond dipoles do not ____.
Example 15
easy
Is XeF4 (square planar) polar or nonpolar?
Example 16
challenge
CO2 and H2O both contain two polar bonds. Using vector addition of bond dipoles, explain why only water has a net dipole.
Example 17
medium
PCl5 has five P-Cl polar bonds. The molecule is trigonal bipyramidal. Polar or nonpolar?
Example 18
easy
Will a polar molecule dissolve well in water?
Example 19
easy
Which dissolves better in water: ethanol or hexane?