Which statement explains why ice floats in liquid water?

Question

1. Water molecules maintain the same bent shape in liquid and solid states.
2. As water molecules go from the liquid to the solid state, their rate of motion decreases.
3. Water molecules maintain the same mass as they transition from the liquid to the solid state.
4. The ordered lattice structure of water molecules in ice is maintained by hydrogen bonds.
5. The arrangement of water molecules in ice results in fewer molecules per unit volume than in liquid water.

Answer 1

Ice floats in liquid water because of the arrangement of water molecules in ice results in fewer molecules per unit volume than in liquid water.

When ice turns from a liquid to a solid state the water molecules keep their hydrogen bonding while a crystalline lattice is formed. This formation of the crystalline lattice creates gaps between the water molecules, so there ends up being more separation between each individual water molecule when water is frozen solid. This extra space or volume that is created for the water molecules makes the solid water less dense than liquid water.  

Water in a liquid state allows the water molecules to move around at a faster rate and at the same time allows them to move closer together. This reduces the space or volume between the individual water molecules when it moves from a solid to a liquid state. This reduction in volume causes the density of liquid water to be slightly higher than solid water or ice.  

Remember the formula for density:

Density =  mass

    ————

    Volume 

As the Volume of any substance increases while keeping the mass constant, 

the Density decreases.

As the Volume of any substance decreases while keeping the mass constant, the Density increases.