Water and Life Flashcards
What type of bond is water made up of?
Water is made up of polar covalent bonds in which the hydrogen has a partial positive charge and the oxygen has a partial negative. Water molecules bond together through very frequent hydrogen bonds which are consistently breaking and reforming.
What are the four main properties of water which contribute to the sustainability of life on Earth?
1) It’s cohesive and adhesive behaviour
2) temperature moderation
3) versatility as a universal solvent
4) expansion upon freezing
What is cohesion and adhesion?
Cohesion is a property of water in which water tends to attract other water molecules creating hydrogen bonds and clinging to each other
Adhesion is when water clings to other substances
How does water moderate temperatures?
Water bodies are known to be great heat banks which can absorb heat and release heat during different climates to moderate temperatures
What does the specific heat of a substance mean?
The specific heat of a substance is the measure of how much heat is required by a substance to change the temperature of 1 gram of water 1 degree Celsius
What is evaporative cooling? How does it contribute to temperature moderation?
Evaporative cooling is a process in which the temperatures of water bodies are moderated from overheating through evaporation. When water evaporates, molecules with the most kinetic energy tend to evaporate first leaving behind those molecules with less kinetic energy providing a cooling function to the surface of the water.
What property of water allows ice, the solid form of water to float on top of liquid water?
Ice, the solid form of water unlike other fluids is less dense in its solid form therefore allowing ice to float on the surface of liquid waters
Why is the solid form of water able to float on ice?
Water molecules expand when frozen.
- When above 4 degrees Celsius, water may behave like other liquids expanding when warmed and condensing when frozen.
- When under less than 4 degrees Celsius, water molecules begin to move slower
- at 0 degrees Celsius, water molecules become locked in place through hydrogen bonds between the molecules keeping the water molecules frozen within a distance
At what temperature is water most dense?
water is most dense in its liquid state at 4 degrees Celsius
How is floating ice beneficial to the environment
The expansion of frozen water molecules is a property which is responsible for allowing marine animals to survive underwater without their environments completely freezing during colder weather.
How are hydronium ions produced by reactions between water molecules?
As water molecules interact with each other and are bound by weak hydrogen bonds, in the case that hydrogen from one water molecule is transferred to the next, this results in a water molecule with one less hydrogen and another with one more. The water molecule with an extra hydrogen molecule is now referred to as a hydronium ion with a charge of +1 and the water molecule with one less water molecule is referred to as a hydroxide ion with a charge of -1.
What is the major difference between an acid and a base?
an acid is a substance which increases the concentration of H+ ions in a solution whereas a base is a substance which decreases the concentration of H+ ions in a solution.
What is the difference between a weak acid/base and strong acid/base
Strong acids are those compounds which completley dissosiate when mixed with water either making a solution more acidic or basic whereas weak bases are those compounds which may donate or accept hydrogen ions though reversably also allow release or accept them back.
What is a buffer substance? provide an example.
A buffer is a substance which regulates the pH of a substance at a specific level by either donating or accepting hydrogen ions depending on the imbalance in their concentrations disturbing the maintenance pH of that substance. (Whether there is excess or not enough H+)
An example is carbonic acid when reacting with water in human blood.
Why does ocean acidification take place and what is its effect on marine life?
As a result of pollution and such which increases the amount of CO2 in the atmosphere, CO2 which dissolves with water results in an increase of carbonic acids in oceans. This results in a decrease in carbonate ions and therefore also suppresses calcification.
