Chapter 2 - Water Flashcards
What is polar covalent bond?
Bond btween hydrogen and oxygen involves unequal sharing of electrons
What type of bond is water?
A polar covalent bond
Why is water polar covalent bond?
Because the nucleus of the oxygen is more attractive to electrons than the nuclei of the hydrogen atoms
What types of charge to hydrogen and oxygen molecule haveV
Hydrogen –> partial positive charge
Oxygen–> partial negative charge
What attraction between water molecules is called what?
Hydrogen bond
What are the cohesive properties of water?
1) they stick to each other due to hydrogen bonding
2) useful for water transport in plants- wAter is sucked through xylem vessels and low pressure
what are adhesive properties of water?
1) hydrogen bonds can form between water and other polar molecules causing water to stick to them
2) useful in leaves- where water adhered to cellulose molecules in cell walls- if water evaporates from the cell walls and is lost from the leaf- adhesive forces cause water to be drawn out of the nearest xylem vessel- keeps walls moist do they can absorb carbon dioxide needed for photosynthesis
What are waters 3 thermal properties?
High specific heat capacity
High latent heat of vaporisation
High boiling point
Properties of high specific heat capacity?
1) hydrogen bonds restrict the motion of water molecules and increases in the temperature of water require hydrogen bonds to be broken
2) requires large amounts of energy to raise heat of water
3) means it’s stable habitat for aquatic organisms
What is a water molecule formed of?
By a covalent bond btween an oxygen atom and two hydrogen atoms
What are the properties of high latent heat of vaporisation?
1) the heat needed to make water become a vapour molecule is called latent heat
2) evaporation has a cooling effect - good evaporative coolant
3) sweating is a good example of the use of water as a coolant
What are the properties of a high boiling point?
1) broad 0•C to 100•C
2) this is the temperature range found in most habitats on earth
What are the solvent properties of water?
1) polar nature of the water molecule means that it forms shells around charged and polar molecules preventing them from clumping together and keeping them in solution
2) it can dissolve charged ions
What types of substances can dissolve in water?
Hydrophilic substances, including polar molecules such as glucose, Sodium and chloride ions
Non polar molecules tend to join together in water to form larger and larger groups- why?
Because water is more attracted to itself then to non polar molecules
