Question

question 3 (2 points)
water molecules are called 1 molecules because they act like little magnets that stick together to form a liquid at room temperature.
in contrast, 2 molecules do not act like little magnets and do not stick together as a liquid, and are more likely to be a gas.
ammonia molecules are attracted to water, and dissolve in water, because ammonia is also a 3 molecule.
a polar bond is also called a dipole. thus, both water and ammonia have dipoles as indicated by the difference in electronegativity, δen.
a. polar b. nonpolar

Explanation:

• Polar molecules have a positive and a negative end (like little magnets) due to differences in electronegativity. Water (\(H_2O\)) has a bent shape, with oxygen being more electronegative than hydrogen. The difference in electronegativity (\(\triangle EN\)) creates a dipole moment, so water is polar.
• Non - polar molecules have either symmetrical shapes (so that the dipole moments cancel out) or very small differences in electronegativity. Non - polar molecules do not have strong intermolecular forces like dipole - dipole forces (which hold polar molecules together as a liquid at room temperature), so they are more likely to be gases.
• Ammonia (\(NH_3\)) has a trigonal pyramidal shape. Nitrogen is more electronegative than hydrogen, creating a dipole moment. Since water is polar and ammonia is also polar, they have similar intermolecular forces (dipole - dipole forces), which allows ammonia to dissolve in water.

Answer:

1. A. polar
2. B. nonpolar
3. A. polar