Question

which statement helps to explain why ice is less dense than liquid water? (a) water molecules make hydrogen bonds at definite angles. (b) cold molecules move less than warm molecules. (c) hydrogen bonds lengthen in the cold. all of the above. both (a) and (b).

Explanation:

Water molecules form hydrogen - bonds at definite angles in ice, creating an open - lattice structure that increases the volume and thus decreases the density. Cold molecules moving less is also relevant as it affects the formation of the ordered structure in ice. While hydrogen bonds do not necessarily lengthen in the cold in a way that directly explains density difference. So, statements (a) and (b) contribute to the explanation.

Answer:

E. Both (a) and (b)