Biology - Properties of water

What is electronegativity?

Why is oxygen more electronegative than hydrogen?

Measures the tendency of an atom to attract a bonding pair of electrons

IDK

how many hydrogen bonds can one water molecule bond to?

four neighboring water molecules

What is a polar covalent bond?

Where are these bonds in a water molecule?

The sharing of electrons unequally between two atoms

Covalent bonds are more stable and harder to break compared to non-covalent bonds

List examples of non-covalent bonds

List the four emergent properties of water that contribute to Earth’s suitability for life

1. cohesion and adhesion

2. ability to moderate temperature

3. form ice that is less dense than water

4. versatility as a solvent

Differentiate between cohesion and adhesion, and how they play a major role in capillary
action

cohesion - force of attraction between molecules

adhesion - force of attraction between different molecules

these two factors help transport water in xylem vessels of plants (capillary action - liquid able to flow in a narrow space without the help of external forces, like gravity)

Define surface tension in relation to hydrogen bonding between water molecules

surface tension: how hard it is to break the surface of a liquid

for water, hydrogen bonds resist stretching and breaking

Define specific heat, and explain why does water have high specific heat

specific heat: amount of heat that is absorbed/lost for one gram of substance to change the temperature by 1 degree Celsius

water has high specific heat because the energy from heat spends time breaking the hydrogen bonds, so it can absorb a lot of heat

Explain how water minimizes temperature fluctuations to within limits that permit life

Because water can float it prevents the entire planet from being a giant sheet of ice

Stabilizes air temp. by absorbing heat from hot air and releasing heat to cooler air, that’s why coastal climates are so mild

Define heat of vaporization, and explain why water has high heat of vaporization

Heat of vaporization: heat a liquid must absorb for 1 gram to be converted to gas

Hydrogen bonds make it difficult for water molecules to escape the liquid state

Define evaporative cooling. Why is this better for life on earth?

When water evaporates, it’s remaining surface cools (think of sweating)

helps cooling for organisms and bodies of water

Define aqueaous solution, solute, solvent, solution, aqueous solution, and hydration shell

Aqueous Solution - a mixture where water is the solvent

Solvent - dissolving agent

Solute - substance that is dissolved

Hydration cell - when a ionic compound is surrounded by a sphere of a water molecule

Solution - mixture of two or more substances