Water

• why is water described as a polar molecule?

  It has an even distribution of charge
• why do hydrogen bonds form between water molecules?

  Hydrogen bonds form between oxygen and hydrogen atoms because of the partially negative charge of an oxygen atom and the partially positive charge of a hydrogen atom interacting with each other due to the opposite charges causing an attraction
• Are hydrogen ions weak?

  Individually hydrogen ions are weak, collectively they are strong
• what are 4 purposes of water?

  Acts as a solvent

  Acts as a transport molecule

  Acts as a coolant

  Acts as a habitat
• Why does water act as a good solvent?

  Polar (hydrophillic) molecules dissolve readily in water due to the polar nature of water. The partial positive charge on hydrogen atoms will attract the negative ions in the solute and the partially negative charge of oxygen will attract the positive ions in the solute.
• what type of molecules/atoms are not attracted to water?

  Non polar AKA hydrophobic molecules and atoms
• What is the significance of cytosol in eukaryotic and prokaryotic cells in terms of water?

  The cytosol is primarily made of water, thus many solutes are able to dissolve within and are easily transported.
• why is water a good transport medium in plants?

  Polar substances can readily dissolve in water. Water is cohesive so it can move up the xylem due to transpiration, as it is a continuous column of water. This is advantageous because it is easier to draw a column instead of individual molecules.
• What is cohesion?

  When water molecules are attracted to each other due to the hydrogen bonds between them.
• What is adhesion in terms of water?

  When water molecules are attracted to their surroundings due to hydrogen bonds forming
• why is water a good coolant, why is this key in animals and plants?

  water has a high specific heat capacity due to the alrge amounts of energy needed to break the hydrogen bonds in several water molecules. This is advantageous because the internal temperatures of animals and plants can remain relatively stable; thus enzymes do not denature or reduce in activity due to temperature fluctuations
• Why is the fact that water has a large specific latent heat of evaporation a good thing, and why does it have it?

  Water has a large specific latent heat of evaporation because of the large amount of energy needed to break the hydrogen bonds between water molecules to turn it into a gas. This provides a cooling effect on plants and animals, and is a way of ridding the organism's vital organs from excess heat
• Why is water a good habitat for aquatic animals?

  It has a large specific heat capacity and large specific latent heat of evaporation- this makes water a good buffer for temperature meaning that it provides a stable environment in terms of temperature- which is good for aquatic animals.
• In terms of cohesion, why is water a good habitat?

  Cohesion provides surface temperature to water. This enables small invertebrates to move and live on the water, providing them a habitat away from predators within the water.
• In terms of density, why is water a good habitat?

  When water freezes, water molecules form a rigid lattice in a way that spaces out water molecules that lessen the density of water. Thus ice floats on top of water and provides a surface habitat for animals