Properties of Water – Maharashtra Board Class 7 Solutions for General Science (English Medium)
MathematicsGeneral ScienceMaharashtra Board Solutions
Solution 1.a:
Water shows anomalous expansion. As the temperature increases from 0°C to 4°C, the density of water increases. The density of water is maximum at 4°C. The surface layer of water in a reservoir freezes at 0°C. However, the temperature of water below the ice is about 4°C. Hence, the water stays below the ice and the aquatic animals in the reservoir can survive in it.
Solution 1.b:
Seawater consists of about 35 grams of salt per litre. Thus, the density of seawater is more than that of the ordinary water. Hence, this makes a person to swim with more ease in the seawater than in the ordinary water.
Solution 1.c:
Water is said to be a universal solvent because many substances dissolve in it.
Solution 1.d:
Water is a colourless, odourless, transparent liquid at normal temperature. It is a chemically neutral substance which makes it an ideal medium for most chemical reactions.
Solution 2:
- The density of water is 1 g/cc.
- A substance that dissolves in a liquid is called a solute.
- When a solute and a solvent mix in each other completely, we get a solution.
Solution 3:
Group ‘A’ | Group ‘B’ |
(a) Anomalous expansion | 2. Water |
(b) Density | 1. Mass/Volume |
(c) Dead Sea | 4. 25% salt |
(d) Water | 3. Compound |