Water Flashcards
What type of bonding is in water?
Covalent bonding
What type of molecule is water?
Polar
What bonds are in water?
Hydrogen
Are hydrogen bonds weak or strong?
Weak but if there are many, they form a strong structure
Why does water have many essential roles in living organisms?
Because of the polarity of water molecules
The presence and number of hydrogen bonds between water molecules
What charge is oxygen?
Weak negatively charged
What charge is hydrogen?
Weak positively charged
Why do hydrogen bonds form?
Between the positive and negatively charged regions of adjacent water molecules
What dissolves in water?
Many ions (NaCl) and polar molecules e.g. glucose amino acids
What does water being a solvent allow?
Allows chemical reactions to occur as dissolved solutes are more chemically reactive when they are free to move
What does water being a solvent allow for metabolites?
They can be transported efficiently (except non-polar molecules as they are hydrophobic)
What does the solvent allow into and out of cells?
Diffusion
What does water having its maximum density at 4 degrees Celsius do for ice?
Ice floats on cold water
What does water having a maximum density at 4 degrees Celsius do for the water layer underneath?
Insulates the water layer underneath- leaving liquid water as a habitat
Metabolite?
A reactant or product in many key reactions e.g. hydrolysis, condensation, photosynthesis, respiration
Enables all chemical reactions to occur
What is SHC?
The energy required to increase the temperature of water by 1 degrees Celsius per gram
Does water have a high or low SHC?
High
Is a large or small amount of energy needed to raise water’s temperature?
A large amount
How many hydrogen bonds are there in water?
2 hydrogen bonds per water molecule
What is required for these hydrogen bonds to break?
A lot of thermal energy and a lot of energy to build these bonds
Does the temperature of water fluctuate a lot?
Not much
What are the advantages of a high SHC for living organisms?
Provides suitable habitats
Able to maintain a constant temperature- water is able to absorb a lot of hear without big temperature fluctuations
Maintain temperature for enzyme activity
What does water in blood plasma do?
Transfers heat around the body to maintain a constant temperature
Adhesion?
Water is able to hydrogen bond to other molecules- enables water to move up the xylem due to transpiration
What is latent heat of vaporisation?
The energy required to change states
Does water have a high or low latent heat of vaporisation?
High
What must occur in order for changes of state to occur?
A large amount of energy must be absorbed by water to break the hydrogen bonds and evaporate
How is the high latent heat of vaporisation an advantage for living organisms?
Only a little water is required to evaporate for the organism to lose a great amount of heat
Provides a cooling effect for organisms (transpiration or evaporation of sweat) -> thermoregulation
Why do water molecules stick together?
Due to lots of hydrogen bonds
What does the strong cohesion allow for in the xylem?
Water moves in an unbroken column/stream
How does water get a firm surface?
Due to cohesion between water molecules
How is a film created on the top of the water?
A body of water meets the air, these hydrogen bonds occur between the top layer of water molecules to create a film on top of the water
What does surface tension allow for leaves and small organisms?
Leaves can float on the water and small organisms can move across the surface
