Water Flashcards
Describe the polarity of water.
Polar molecule due the presence of oxygen, which is electronegative, which creates a dipole in the molecule.
Describe the distribution of partial charges in water.
Oxygen is slightly negative due to the presence of lone pairs.
Hydrogen is slightly positive as electron density is drawn closer to the hydrogens.
What are hydrogen bonds?
Weak attractive forces between molecules from a slightly positive hydrogen to a slightly negative N, O or F atom.
What does a high specific heat capacity of water mean?
Water can absorb a large amount of energy before its temperature changes.
Why is a high specific heat capacity beneficial for aquatic organisms?
Makes the temperature of the water more stable than land.
How does specific heat capacity help with enzymes?
Specific heat capacity maintains a constant internal body temperature, keeping enzymes at an optimum.
What does high latent heat of vaporisation mean?
Water can absorb a lot of energy before hydrogen bonds break and water evaporates.
How does a high latent heat of vaporisation help with cooling mechanisms in animals.
Lots of heat can be lost from the body rapidly in a small amount of sweat, preventing water loss.
What is cohesion?
Water molecules stick together due to the presence of hydrogen bonds.
Explain how cohesion occurs in transpiration.
Water sticks to each other when travelling up the xylem to prevent the column of water from breaking.
What is surface tension and why does it happen?
Surface tension is when the top layer of water doesn’t break.
This is due to cohesion which allows small animals such as pond skaters to walk on water.
Describe how solvents work.
Polar molecules, like water, separate ionic compounds. The slightly positive end of water attracts the negative ion and the slightly negative end of water attracts the slightly positive ion.
Give 2 examples of water acting as a solvent in plants/animals.
In animals, it acts as a medium where metabolic reactions occur.
In plants, it can transport minerals such as nitrates which are needed to make amino acids.
Why does water act as a metabolite?
It is reactive.
Give 2 examples of reactions where water acts as a metabolite.
Condensation/Hydrolysis.
