1.1 Properties Of Water Flashcards
Polarity makes water a polar molecule. How?
- unequal sharing of electrons
What is cohesion?
- attraction of molecules for other molecules of the same kind
What type of bonds increase cohesive forces of water?
- hydrogen bonds between water molecules hold them together and increase cohesive forces
What does cohesion allow to happen? (2)
- allows for the transport of water and nutrients against gravity in plants
- responsible for surface tension
What is surface tension?
- property allowing liquids to resist external force
What is adhesion?
- The clinging of one molecule to a different molecule
- due to the polarity of water
What does adhesion allow for in plants?
- allows for water to cling to the cell walls to resist the downward pull of gravity
What is capillary action?
- the upward movement of water due to the forces of cohesion, adhesion, and surface tension
When does capillary action occur?
- when adhesion is greater than cohesion
Why is capillary action important to plants?
Important for transport of water and nutrients in plants
What is high specific heat in water? (2)
- water resists changes in temperature
- the amount of energy required to raise 1 g of water by 1 degree Celsius
How does water have a high specific heat? (2)
- through hydrogen bonds
- must be absorbed to break oxygen bonds, but heat is released when hydrogen bonds form
Why is high specific heat important? (3)
- it moderates air temperature because large bodies of water can absorb heat in the day and release heat at night
- stabilizers ocean temperature, which benefits marine life
- organisms can resist changes in their own internal temperature
What is evaporative cooling? (2)
- Water has a high heat vaporization
- the molecule with the highest kinetic energy leave as gas
Why is evaporative cooling important? (4)
- Moderates Earth’s climate
- Stabilizes temp in lakes and ponds
- Prevents terrestrial organisms from overheating (like sweating in humans)
- Prevents leaves from becoming too warm in the sun
What is density (floating ice)?
- as water solidifies, it expands and becomes less dense due to the hydrogen bonds
How does floating ice occur?
- when cooled, water molecules move too slowly to break bonds
- hydrogen bonds cause water molecules to form a crystalline structure (creates lots of space meaning less density)
Why is floating ice important?
Allows marine life to survive under floating ice sheets
What is a solvent?
- dissolving agent in a solution
What is a solution?
- homogenous mixture of two or more substances
What is a solute?
- substance that is dissolved (salt)
Why is water a versatile solvent? (2)
- it’s polar molecules are attracted to ions and other polar molecules it can form hydrogen bonds with
Note that water is a universal solvent because it can dissolve other molecules due to its polarity
What does “like dissolve like” mean? (2)
- water can interact with sugars or proteins containing many oxygen and hydrogen
- water will form hydrogen bonds with the sugar or protein to dissolve it
How will water interact with ionic compounds? (3)
- The partially negative oxygen in the water will interact with a positive atom
- the partial positive hydrogen in water will interact with a negative atom
- dissolves ion
What are the 7 properties of water?
- Polarity
- Cohesion (surface tension)
- Adhesion
- capillary action
- Temperature control (high specific heat, evaporative cooling)
- Density (floating ice)
- Solvent (versatile and universal solvent)
