Why is NH3 (ammonia) polar? @wbreslyn

Uploaded June 2025 | Updated September 2026, 2 weeks ago

We’ll use the Lewis structure and the PhET molecular model builder to figure out why ammonia (NH₃) is a polar molecule. First, we draw the structure and spot that lone pair on nitrogen. That lone pair pushes the hydrogen atoms down, giving NH₃ a bent, asymmetrical shape.

Since nitrogen is more electronegative than hydrogen, it pulls electrons toward itself—so we get a partial negative charge on nitrogen and partial positives on the hydrogens. That gives us poles, and that means ammonia is polar.

Try building the molecule yourself with this PhET simulation:
https://phet.colorado.edu/sims/html/molecule-shapes/latest/molecule-shapes_en.html

$Convert 4.5 L to mL (4.5 Liters to Milliliters) To convert 4.5 liters (L) to milliliters (mL), you can use the following steps. Note that the L will cancel out as you perform the conversion, leaving only mL: Conversion Factor: 1 liter (L) = 1000 milliliters (mL) Start with the quantity you want to convert (4.5 L) and set up a ratio where the original unit (L) is in the denominator and the target unit (mL) is in the numerator, using the conversion factor: Conversion factor: 1000 mL / 1 L Write the quantity you want to convert (4.5 L) as a fraction over 1: 4.5 L / 1 Multiply this fraction by the conversion factor: (4.5 L / 1) * (1000 mL / 1 L) Notice that the units of liters (L) in the numerator and denominator cancel out, leaving only the units of milliliters (mL): (4.5 * 1000) / (1 * 1) mL = 4500 / 1 mL = 4500 mL So, 4.5 L is equivalent to 4500 milliliters. The units of liters cancel out during the conversion process, leaving only milliliters as the final unit.$

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$Convert 7.5 L to mL (7.5 Liters to Milliliters) To convert 7.5 liters (L) to milliliters (mL), you can use the following steps. Note that the L will cancel out as you perform the conversion, leaving only mL: Conversion Factor: 1 liter (L) = 1000 milliliters (mL) Start with the quantity you want to convert (7.5 L) and set up a ratio where the original unit (L) is in the denominator and the target unit (mL) is in the numerator, using the conversion factor: Conversion factor: 1000 mL / 1 L Write the quantity you want to convert (7.5 L) as a fraction over 1: 7.5 L / 1 Multiply this fraction by the conversion factor: (7.5 L / 1) * (1000 mL / 1 L) Notice that the units of liters (L) in the numerator and denominator cancel out, leaving only the units of milliliters (mL): (7.5 * 1000) / (1 * 1) mL = 7500 / 1 mL = 7500 mL So, 7.5 L is equivalent to 7500 milliliters. The units of liters cancel out during the conversion process, leaving only milliliters as the final unit.$

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