Question

Molecules can be polar because of the unsymmetrical distribution of electrons. The dipole moment, μ, is a measure of the net polarity and is defined as the charge 1.87×10−20 C , in coulombs, times the distance between the charges, which is estimated by the bond length, r, in meters:

μ=Q×r.
The SI unit of dipole moment is the coulomb-meter (C⋅m), but another common unit is the debye (D). The two are related as 3.336×10−30 C⋅m=1 D

A) 2.5 D
B) 5 D
C) 10 D
D) 15 D

Answer 1

Molecules with polar covalent bonds can have a dipole moment due to an unsymmetrical distribution of charge. The dipole moment is calculated with μ=Q×r and typically expressed in debye (D), with the conversion being 1 D = 3.336×10−30 C·m. The correct answer to the student's question is therefore 5 D.

Step-by-step explanation:

Molecules can exhibit a measurable property called a dipole moment due to an unsymmetrical distribution of electrons, which results in polar covalent bonds. The bond dipole moment is a vector quantity with both magnitude and direction and can be calculated using the formula μ=Q×r, where Q represents the magnitude of the partial charges, and r represents the distance between the charges. In the SI unit system, the dipole moment is measured in coulomb-meters (C·m), but it is commonly expressed in a unit known as the debye (D), with the conversion factor 1 D = 3.336×10−30 C·m.

To answer the given question regarding the dipole moment where the charge is 1.87×10−20 C, we need to make use of the conversion factor. No calculation is necessary as the question provides the scale relating coulombs-meters to debye. Therefore, the answer to the question is simply a matter of understanding the provided conversion factor. For example, if we have 1 D = 3.336×10−30 C·m then 5 D would be equal to 5 times that amount in C·m. As such, the correct unit conversion would be 5 D.