2.2 water

Question 1

ion

Answer 1

an atom with a + or - charge due to unequal amount of e^- and protons

Question 2

Polar molecule

Answer 2

A molecule exhibiting seperation of charge due to unequal distribution of e^-

Question 3

Isotope

Answer 3

Atoms with same amount of e^- and protons, but different neutrons

Question 4

Water molecules

Answer 4

Are polar, Oxygen has slightly more negative chareg due to its size

Have covalent bonds, share e^-

Dipolar molecule

Have hydrogen bonds between the hydrogen and oxygen (ONLY WHEN H2O binds to another H20)

Can form 4 hydrohen bonds (2 O2 & 2 H)

Question 5

Cohesive and adhesive properties of water

Answer 5

Hydrogen bonds allow water to be cohesive (sticks to same molecule)

Water is adhesive (it can stick to other polar or ionic substances)

Cohesion allows water to flow up the xylem of plants against gravity due to cappilary action while adhesion adheers water to xylem

Question 6

Thermal properties of water

Answer 6

Has a high specific heat capacity (High energy to break hydrogen bonds)

Has a high latent heat of vapourizastion (Liquid to a gas)

Question 7

Water as a coolant

Answer 7

When water evaporates it removes a lot of energy from the system (Sweat)

Question 8

Comparison of thermal properties of water to methane

Answer 8

Higher heat of vaporization

Higher melting and boiling point

Higher specific heat capacity

Higher heat of fusion (Liquid to solid)

Methane has no hydrohen bonds

Question 9

Hydrophilic and hydrophobic substances

Answer 9

Phospholipid bilayer:

Phospahte head is hydrophilic

Fatty acid tail is hydrophobic

Amphipathic = have both hydrophilic and hydrophobic properties (soap)

Question 10

Solvent properties of water

Solvent = Dissolving something

Answer 10

Is a good solvent because it is a polar molecule

Can dissolve polar solutes easily

Ionic solids dissociate in water (Salt NaCl):

Negative O2 side of water attracts to Na⁺

Positive H attract to Cl^-