Topic 2.2: Water Flashcards
What is water made up of
Two hydrogen atoms covalently bonded to an oxygen atom
Why is water described as being polar
Because it has a slight charge difference across the different poles of the molecule
What are the properties of water
Thermal
Cohesive
Adhesive
Solvent
What is thermal properties of water
When water can absorb much heat before changing state (requires the breaking of hydrogen bonds)
What is cohesive and adhesive properties of water
When water will stick to other water molecules (cohesion). and charged substances (adhesion)
What is solvent properties
When water dissolves polar and ionic substances
How does water have the capacity to absorb significant amounts of heat before changing state
Because of the extensive hydrogen bonding between water molecules
The bonds need to be broken before a change in state can occur, requiring the absorption of energy (heat)
What are the differences between water and methane
water is polar while methane is non-polar
Water can form intermolecular hydrogen bonds while methane can only form weak dispersion forces
Why does water absorb more heat before changing state
It has a significantly higher melting and boiling point
Water has a higher specific heat capacity
Water has a higher heat of vaporization
Water has a higher heat of fusion
What are the uses of water as a coolant in sweat
The evaporation of water as sweat is a fundamental mechanism to humans as a means of cooling down
What is cohesion
the ability of like molecules to stick together
water is strongly cohesive (forming hydrogen bonds)
What is adhesion
The ability of dissimilar molecules sticking together
Water will form intermolecular associations with polar and charged molecules
What is the significance of cohesive and adhesive properties
Cohesive properties explain its surface tension
Adhesive properties explain its capillary action
What is surface tension
The high surface tension of water makes it sufficiently dense for certain smaller organisms to move along the surface
What is capillary action
It is necessary to allow water to be transported up plant stems through a transpiration stem
