Structure of Water and Hydrogen Bonding Practice Test

A student compares liquid water and ice at the same volume and finds that ice has fewer water molecules in that volume than liquid water. Water molecules are polar and can form hydrogen bonds. In liquid water, hydrogen bonds form and break rapidly, allowing molecules to pack relatively close. In ice, hydrogen bonds stabilize a more open, repeating arrangement that holds molecules farther apart. This structural difference arises from hydrogen bonding patterns between water molecules. Which statement best explains why ice is less dense than liquid water?

Which statement best explains why ice is less dense than liquid water?

A plant’s xylem contains narrow tubes filled with water. Water molecules are polar and form hydrogen bonds with each other, creating cohesion. Water molecules can also form hydrogen bonds with polar groups in the cell wall materials lining xylem, creating adhesion. In narrow tubes, these intermolecular attractions influence how a continuous column of water can be maintained without breaking into separate droplets. The behavior depends on hydrogen bonding among water molecules and between water and the tube surface. Which feature best explains how water can remain as a continuous column in xylem?

Which feature best explains how water remains a continuous column in narrow xylem tubes?