water

Why is water important?

metabolic reactions,
transport medium,
temp stability,
removal of toxins,
turgidity,
component of cells,
habitat

What are the properties of water?

cohesion, adhesion, surface tension, flows, good solvent, less dense when ice, high SHC, high latent heat, polar forms H bonds

Structure of a water molecule:

2 delta positive H, 1 delta negative O, covalent bond, O more electronegative, pulls electrons towards it

Why are water molecules attracted to each other and what do they form?

they're polar, slightly positive H of one attracted to slightly negative O of other, forms hydrogen bond

What is a hydrogen bond?

weak electrostatic attraction between hydrogen and oxygen

What is cohesion?

water molecules sick together due to hydrogen bonding

What is surface tension?

caused by cohesion between water molecules at the surface, where hydrogen bonds pull them inwards to form a thin skin

Why is cohesion and surface tension important for organisms?

forms a strong layer on which small animals can walk on

Diagram of water molecules bonding:
What bond is this?

hydrogen bond

How do water, heat and temperature behave?

hydrogen bons between water molecules require lots of energy/heat to break, high specific heat capacity (4.2kJ needed to raise temp of 1kg of water by 1 degree)

Why is water having a high specific heat capacity useful?

resists rapid temp change, helps maintain constant body temp and stable environments

What's the latent heat of evaporation like in water?

high latent heat of evaporation, sweat absorbs heat energy from body before evaporating

Why is a high latent heat of evaporation useful?

removes heat, cools living things, stable temp

What processes help heat loss via evaporation?

sweating and transpiration

Why is this important for organisms?

sweat cools down, transpiration, temp stability

Why is water a good solvent?

water is polar, has positive and negative charges which attract charges on other molecules, ions

What feature of water allows transport of substances?

water can flow, substances can dissolve

Why is water being a good solvent important for organisms?

it can dissolve and transport essential substances, allowing metabolic reactions and processes to occur

What's the significance of water being a good solvent and the ionic bonding of NaCl?

produces charged ions that water's polarity attracts to and separates, dissolving them to be transported

How does water behave in terms of density?

water's dense, H bonds pull molecules close,
when frozen, more stable bonds as ice is less dense, molecules further apart, floats

How does water behave in terms of viscosity?

viscous as molecules are attracted to each other via H bonds, low viscosity, bonds break and reform, flows

Why is density important for organisms?

aquatic animals can change density so easier to float, swim bladder, ice insulates water below so stable habitat in winter

Why is viscosity important for organisms?

low viscosity, flows, allows transport in blood, xylem, phloem

What are the bonds in liquid water like regarding density?

more dense, bonds break and reform so water flows

What are the bonds in solid water (ice) like regarding density?

less dense, stable H bonds hold molecules closer