Question

electrical bonding investigation plan quick check
water melts at 0°c. a student observes a liquid that melts at 10°c. which conclusion can the student reasonably draw? (1 point)
○ the average kinetic energy of water molecules is greater than the average kinetic energy of the molecules in the unknown liquid.
○ the bonds between water molecules are stronger than the bonds between molecules in the unknown liquid
○ the molecules in water are farther apart than the molecules in the unknown liquid.
○ the electrostatic forces between molecules in the unknown liquid are stronger than the electrostatic forces between water molecules.

Explanation:

To solve this, we analyze each option:

1. Kinetic Energy: Average kinetic energy depends on temperature. Water melts at \(0^\circ\text{C}\), unknown at \(10^\circ\text{C}\). Higher temp means higher KE for the unknown, so this is wrong.
2. Bond Strength (Water vs. Unknown): Melting point relates to intermolecular forces (not covalent bonds in water molecules). Water’s melting point is lower, so its intermolecular forces are weaker, not stronger. Wrong.
3. Molecular Spacing: In liquid state, both are liquids, so spacing is similar. Melting point doesn’t directly indicate liquid molecular spacing. Wrong.
4. Electrostatic Forces (Intermolecular): Higher melting point means more energy is needed to break intermolecular forces. The unknown melts at \(10^\circ\text{C}\) (higher than water’s \(0^\circ\text{C}\)), so its intermolecular (electrostatic) forces are stronger. Correct.

Answer:

The electrostatic forces between molecules in the unknown liquid are stronger than the electrostatic forces between water molecules.