A1.1 Water Flashcards
1
Q
What is the structure of water
A
- Polar covalent bond due to unequal attraction of electrons.
– Nuclei of O2 is larger hence, stronger pull.
– Covalent bonds are strong due to shared electrons. - Hydrogen bonds between multiple molecules of water – weak bonds due to attraction of polar molecules.
2
Q
What are the chemical properties of water?
A
- Cohesion:
- Water sticks to each other due to its polar nature, forming hydrogen bonds.
- Strong cohesive forces causes surfaces tension in the surface of a body of water –> allows insects to stick to surfaces,
- Allows transpiration of water through transpiration pull. - Adhesion:
- The polarity of water allows it to attract to other polar molecules.
- Capillary action – prevents water from dropping when moving up the xylem
- Water forms a meniscus as it adheres to the polar glass. - Solvent:
- Polar and hydrophilic substances dissolve in water due to polarity.
- Water dissolves solutes to form aqueous solution
– Good medium for enzyme-catalysed reactions and transporting dissolved substances.
3
Q
What are the physical properties of water?
A
- Buoyancy:
- An upward force exerted on an object placed in a medium.
– Objects less dense or as dense as water will float. - Viscosity:
– Water has low viscosity, little resistance to flow - Specific heat capacity:
- High heat capacity due to restriction of hydrogen bonds. - Poor conductors, good insulators
4
Q
Explain movement of water (hint: water potential)
A
- Water moves from a hypotonic (less solute) to a hypertonic solution across a partially permeable membrane via osmosis.
5
Q
Effect of hypotonic and hypertonic solutions
A
In cells lacking cell walls:
- Hypotonic: burst under extreme turgor pressure
- Hypertonic: plasmolyze, crenate
6
Q
Uses of isotonic solutions
A
- Intravenous fluid – balances solute conc. in the body
- Organ transplant – immersed in the solution before procedure.
