Question

1. when ice is melting, the heat being added causes:

molecular motion to increase.
hydrogen bonds to form.
molecular motion to decrease.
the temperature of the ice to increase.
hydrogen bonds to break.

Explanation:

When ice melts, it undergoes a phase change from solid to liquid. In ice (solid water), water molecules are held in a rigid lattice structure by hydrogen bonds. As heat is added during melting, the energy is used to break these hydrogen bonds. While molecular motion does increase when substances are heated in general, during the phase - change of melting (a constant - temperature process for pure substances at a given pressure), the added heat is specifically for breaking intermolecular forces (hydrogen bonds in water's case) rather than increasing the temperature (the temperature remains at the melting point until all the ice is melted). Forming hydrogen bonds would be the opposite of what happens during melting (it would be more like freezing), and molecular motion decreasing is incorrect as energy is being input.

Answer:

hydrogen bonds to break.