A1.1 Water Flashcards
Why is water referred to as a universal solvent?
Because many things dissolve in it
What sort of bonds are between the H and O atoms in water?
Polar covalent bonds
In water the hydrogens have a slight ___ charge and the oxygen has a slight ___ charge. Overall the molecule has ___ charge.
positive, negative, no
What sort of bonds form between water molecules?
Hydrogen
Why are water molecules cohesive?
Because of the hydrogen bonds that form between the molecules
Why can some animals live/walk on water?
Because the water molecules at the surface are more attracted to each other than they are to the air, the hydrogen bonds (cohesion) allow this.
Adhesion
The attraction of water to charged or polar surfaces. It allows water to flow against gravity (capillary action).
How does adhesion work?
Hydrogen bonds form between the H on water and a charged surface.
Hydrophyllic
“water loving”, substances that dissolve easily
Hydrophobic
“water hating”, do not dissolve in water
Aqueous solutions
Solutions containing water
Why is water able to be retained on earth
- Temperatures are low enough for it to condense into a liquid state
- Earth is large enough that its gravitational pull keeps water on or near its surface
- shape of the earths orbit
How do theories suggest water came to be on earth?
Initially the earth consisted of molten rock and so conditions were too hot for water to be retained, over a long time the earth cooled. It is theorised that then asteroids containing hydrated minerals “seeded” water on earth when they became a part of the earth’s crust
What supports the asteroids “seeded” water theory?
There are similar ratios of heavy to typical water in sea water to asteriods.
Heavy water/ deuterium
Its hydrogen atoms contain a neutron making it heavier than typical water.
What must a planet have to support life?
Liquid water
Goldilocks/ habitable zone
An area of our solar system relative to our sun that allows water to exist on the planets in it.
