2.7. Water

Question 1

Water is important for three reasons

Answer 1

•It is a major component of cells, typically forming about 70% and 95% mass of the cell. Your body is about 60% water.
•It provides an habitat for those organisms that live in water; three quarters of the planet is covered in water
•It is a liquid and so provides a medium for molecules and ions to mix in and hence a medium life can evolve in

Question 2

Why does water exist in liquid state while such a small molecule would exist as a gas around normal Earth temperatures

Answer 2

Because it has hydrogen bonding as it makes the bonding of water molecules making it more difficult to separate them and thus requires higher temperatures to break the bonds.

Question 3

Why is water an excellent solvent for ions and polar molecules

Answer 3

Water is a polar molecule and therefore are attracted to the ions and polar molecules and therefore collect around them and separate them.