2.2 Water Flashcards
Why is water polar? and draw a diagram?
In a water molecule there is two hydrogen and an oxygen but because oxygen has a larger mass (more protons) electrons sit closer to it. This makes the oxygen molecule slightly negative and hydrogen molecules slightly positive.
Draw the hydrogen bond between two water molecules and what two elements does this happen between?
-The slightly negatively charged oxygen is attracted to the slightly positively charged hydrogen (diagram is wrong should be other way round)
What are condensation and hydrolysis reactions
-Condensation reactions are when two molecules join together with the removal of water they usually join via two OH groups
-Hydrolysis reactions are when one molecule splits into two with the addition of water
Why does water have a high specific heat capacity
-Specific heat capacity is a measure of kinetic energy of molecules
-Water has hydrogen bonds holding molecules together tightly so therefore lots of energy is required to raise the temperature and kinetic energy
Why is it important that water has a high specific heat capacity
-So that living things(prokaryotes and eukaryotes) have a stable temperature for enzyme controlled reactions
-Aquatic organisms environment doesn’t fluctuate in temperature a lot making it easier for them to survive.
Why does water have a high latent heat of vaporisation and why is this important
-Hydrogen bonds mean lot of energy is required to break bonds and water to become gaseous
-Therefore it can be used as a coolant as lots of energy is released when it evaporates e.g sweat
Why is water cohesive and adhesive
-Water is polar so therefore are attracted to eachother(Cohesion) and is therefore attracted to other polar molecules(adhesion)
Why is it important that water is cohesive and adhesive
-Helps keep blood together and water in transpiration is pulled up due to cohesion.
-This also causes surface tension which creates a layer of water able to resist a force because the water molecules are being pulled inwards due to cohesion.
Why does water have a lower density when solid
and why is this important
-When water becomes solid it forms four covalent bonds and creates a lattice shape which is less dense than liquid water
-Therefore when it’s cold ice will form an insulative layer on the top of a lake for e.g and prevent heat loss creating a stable environment for aquatic organism
