Question

Hlo everyone

Plz answer my question which is in the pic ​

Answer 1

Answer:

The anomalous expansion of water is an abnormal property of water whereby it expands instead of contracting when the temperature goes from 4o C to 0o C, and it becomes less dense. The density becomes less and less as it freezes because molecules of water normally form open crystal structures when in solid form.

Answer 2

Anomalous Expansion of Water:-

• A common observation seen in the behaviour of the substances is that they expand when heated as the density decreases and vice versa takes place when the material is cooled. This is how substances generally react to heat. Let us now look at how water behaves when heated.
• The general tendency of cold water remains unchanged until 4o C. The density of water gradually increases as you cool it. When you reach 4oC, it’s density reaches a maximum. What water does next will astound you. When you cool it further to make some ice, i.e. 0oC, water expands with a further drop in temperature, meaning the density of waterdecreases when you cool it from 4oC to 0oC. The below graph explains this behaviour.
• The effect of this expansion of water is that the coldest water is always present on the surface. Since water at 4oC is the heaviest, this water settles on the bottom of the water body and the lightest ie the coldest layer accumulates on the top layer. So in the winter, the top of the water is always the first to freeze over. Since ice and water both are a bad conductor of heat, this top layer of ice insulates the rest of the water body from the cold of the winter, thereby protecting all the life in the water body. Now you can truly comprehend how essential the anomalous properties of water are for life.