1.7: Water Flashcards
Describe the strength of hydrogen bonding
individually weak bond but En masse it is quite strong
Explain how the polarity of a water molecule is created
oxygen is partial negative, and both hydrogen atoms are partial positive and so water is a dipolar molecule
Is water a solvent?
yes
what is a solvent
a liquid that is able to dissolve other substances
list 8 properties of water that are biologically important
1 - universal solvent
2 - high latent heat and evaporation
3 - high specific heat capacity
4 - metabolite
5 - ice less dense than water
6 - cohesion
7 - low viscosity
8 - transparent
How is water being a universal solvent biologically important?
Chemical reactions inside cells happen in aqueous solutions
Water is the main transport medium in organisms
How is water having a high latent heat and evaporation biologically important?
acts as a coolant - heat is lost from a surface when water evaporates from it, acting as a cooling mechanism - sweating
How is water having a high specific heat capacity biologically important?
acts as a temperature stabiliser - cells can absorb/lost a lot of heat energy but only show small temperature changes and so organisms can live in extreme climates
How is water being a metabolite biologically important?
Water is required in photosynthesis, in condensation reactions to synthesise biological polymers, and in digestion of polymers via hydrolysis
How is ice being less dense than water biologically important?
Thermal insulation - Ice floats on water insulating organisms to live below it
How is water having cohesive properties biologically important?
Transport medium - long columns of water molecules don’t break - water being drawn up xylem vessels / insect’s body supported on surface of water
How is water having a low viscosity biologically important?
Water can flow easily therefore act as a lubricant - mucus in the digestive system
How is water being transparent biologically important?
Light can pass through it so underwater plants can photosynthesise
How does salt affect the cohesive properties of water
makes water less cohesive
How does water have a high specific heat capacity
The breaking of many hydrogen bonds absorbs a significant amount of heat energy and so water can absorb a lot of heat energy but only show a small change in temperature
