What is the density of water (H20) at 4°C, which is just above the freezing point?

1.0 g/cm3

Explanation:

Water behaves anomalously since it contracts when cooled from any temperature until 4°C and begins to expand below this temperature. Thus water expands when cooled between 4°C to 0°C.

It then follows that water has its maximum density at 4°C. The maximum density of water is 1.0 g/cm3. This is the density of water at 4°C.