Question

why does ice float on liquid water, unlike most solid substances? * 2 points
ice is less dense due to expanded hydrogen bonding
ice experiences reduced gravitational attraction
ice has higher thermal conductivity
ice has lower molecular weight
what biological mechanism allows water striders to walk on waters surface? * 2 points
molecular vibration
electrostatic charge
surface tension from hydrogen bonding
magnetic repulsion
how does water help regulate body temperature through evaporation? *
by creating electrical currents
by absorbing thermal energy during phase change
by generating internal heat
by compressing surrounding molecules

Explanation:

• For the first question: Ice floats on water because hydrogen bonding in ice creates an open - lattice structure, making it less dense than liquid water. Gravitational attraction is a universal force and not reduced for ice. Thermal conductivity and molecular weight (ice and water have the same molecular formula \(H_2O\)) are not relevant to why ice floats.
• For the second question: Surface tension from hydrogen bonding allows water striders to walk on water. Molecular vibration is related to temperature and not this phenomenon. Electrostatic charge and magnetic repulsion are not the mechanisms at play here.
• For the third question: When water evaporates (a phase change from liquid to gas), it absorbs thermal energy. Electrical currents are not created in the body due to water evaporation for temperature regulation. Water does not generate internal heat during evaporation for this purpose, and compressing surrounding molecules is not relevant.

Answer:

• First question: Ice is less dense due to expanded hydrogen bonding.
• Second question: Surface tension from hydrogen bonding.
• Third question: By absorbing thermal energy during phase change.