[OLD] Biological Molecules - Water Flashcards
Chemical formula of water
H2O
What is a polar molecule?
A molecule with areas of positive and negative electrical charge
Is water a polar or non-polar molecule?
Polar
What charge do the hydrogens have?
A small positive charge
What charge does the oxygen have?
A small negative charge
How do hydrogen bonds form between water molecules
The positive end of one water molecules attracts to the negative end of another, the attraction forming a weak H bond
Are the H bonds in water between 2 different water molecules or within a water molecule?
Between 2 different water molecule
What are the bonds joining the 2 hydrogen and single oxygen atoms in water?
Covalent bonds
Why does water have thermal stability?
It has high melting and boiling points as more heat energy has to be provided to break the H bonds
Why is the thermal stability of water important?
Temperature changes of large bodies of water are minimised, leading to a more stable environment. Easier for organisms to maintain constant body temp for enzyme activity.
Evaporation can be used to refer,one a lot of heat energy from animal’s skin to cool it e.g sweating, panting, elephants splashing themselves with water.
What makes water molecules cohere?
Hydrogen bonds
Why is cohesion in water important?
So water can move up the xylem and pond skaters can stay on the waters surface
Why is water a liquid at room temperature and pressure?
Hydrogen bonds hold water molecules together
What do the polar ends of water’s moe,clues allow it to do?
Bond to other polar molecules, breaking them up and dissolving them
Why do icebergs float?
Ice is less dense than water, as in ice H bonds form a lattice in which the water molecules are actually spaced further apart than on liquid water.
