Question

A neutral ammonia (NH\(_3\)) molecule in its vapour state has an electric dipole moment of magnitude \( 5 \times 10^{-30} \) C·m. How far apart are the molecule's centers of positive and negative charge?

• A. \( 4.125 \times 10^{-12} \) m
• B. \( 3.125 \times 10^{-12} \) m
• C. \( 3.125 \times 10^{-6} \) m
• D. \( 4.125 \times 10^{-6} \) m

Hint:

The separation distance between charges in a dipole is given by \( d = \frac{p}{q} \). - Ensure charge \( q \) is in Coulombs and dipole moment \( p \) in C·m before calculation.

Answer 1

The Correct Option is B

Step 1: Using the Dipole Moment Formula The dipole moment \( p \) is given by: \[ p = q d. \] Solving for \( d \): \[ d = \frac{p}{q}. \]
Step 2: Substituting the Given Values Given: \[ p = 5 \times 10^{-30} \text{ C·m}, \quad q = 1.6 \times 10^{-19} \text{ C}. \] \[ d = \frac{5 \times 10^{-30}}{1.6 \times 10^{-19}}. \] \[ d = 3.125 \times 10^{-12} \text{ m}. \] Thus, the correct answer is: \[ \boxed{3.125 \times 10^{-12} \text{ m}}. \]