Ap Bio Chapter 3 Water And Life Flashcards
Why do the electrons of a covalent bond in water molecules spend more time closer to oxygen than to hydrogen ?
Oxygen is more electronegative than hydrogen
What does polar covalent bonds in water molecules result in ?
Hydrogen bonding
What is a polar covalent bond
A covalent bond between atoms that differ in electronegativity in which the shared electrons are pulled closer to the more electronegative atom making it slightly negative and the other atom slightly positive.
What is a polar molecule
A molecule that has an unequal sharing of electrons and it overall charge is unevenly distributed
How strong are hydrogen bonds when water is in its liquid form
Fragile
What are the four emergent properties of water that contribute to earths suitability for life
Cohesive behavior , ability to moderate temperature, expansion upon freezing , and versatility as a solvent
Te quantity of heat required to raise the temperature if 1 kilogram of water by 1 degree Celsius
Kilocalories
How many calories are equal to one joule
0.239cal
How many joules equals one calorie
4.184 J
When a sugar cube is dropped into water , what is the solution, the solute and the solvent
Water+sugar =solution
Sugar is the solute
Water is solvent , it is aqueous
If water were a universal solvent what would the world be like
Everything in water would dissolve including is as well as containers even animals .
How does a non ionic compound dissolve In water
Compounds that are made up of non ionic polar molecules dissolve when water molecules surround each of the solute molecules forming hydrogen bonds with then
What is the molecular mass of table sugar (sucrose) C12H22O11, tha mass of carbon is 12, the mass of hydrogen is 1 and the mass of oxygen is 16
342 Daltons
Mole (mol)
Represents 6.02 X 10^23
How many Dalton’s are in 1 g
6.02 X 10^23
What is the advantage of measuring the quantity of chemicals in moles
The mole of one substance has exactly the same number of molecules as a mole if any other substance
If a molecular mass of a substance :A is 342 Daltons and substance :B is 10 Daltons , how many grams of a would have the same number of molecules as 10 g of :B
342 g
How would we make a liter of solution consisting of 1 mol of sucrose dissolved in water ?
Measure out 342 grams of sucrose and then gradually add water while stirring until the sugar was completely Dissolved. Then add enough water to bring the total volume of the solution up to one liter
Viewing behavior as the result of nervous system functions and biology
Neurobiological approach
Viewing behavior as the product of learning and associations
Behavorial approach
We are the end result of all the different events we have been exposed to throughout life and of the types of responses we have made to them
Behavorial approach
Believing that people are good and capable of helping themselves
Humanistic approach
We are in control of our destines and all of us can make our lives worthwhile
Humanistic approach
Believe that the environment does not force us to become anything , instead it acts as a background for our internal growth
Humanistic approach
A system of viewing the individual as the product of unconscious forces
Psychoanalysis
Emphasizing how humans use mental processes to handle problems or develop certain personality characteristics
Cognitive approach
The most important human ability in this approach is that we can take information from the environment , analyze it and come up with a solution to almost any problem
Cognitive approach
In a water molecule, which substance is more electronegative
Oxygen
What are the polar covalent bonds
The electrons of the covalent bonds spend more time closer to oxygen than to hydrogen
What makes water a polar molecule
The unequal sharing of electrons and waters v like shape
What is a polar molecule
A molecule where it’s overall charge is unevenly distributed
Region of a water molecule that has a partial negative charge
Oxygen
Region of the molecule that has a partially positive charge
Hydrogen
Why are there charged regions in a water molecule
Charged regions in a water molecule are due to its polar covalent bonds
Why do hydrogen bonds form in water
Oppositely charged regions of neighboring water molecules are attracted to each other forming hydrogen bonds
What factors does cohesion due to hydrogen bonding contribute to water
It contributes to the transport of water and dissolved nutrients against gravity in plants
What role does adhesion play in plants
Adhesion of water to cell walls by hydrogen bonds help counter the downward pull of gravity
Why does water have a high surface tension
Because if the collective strength of its hydrogen bonds
How does water moderate air temperature
By absorbing heat from air that is warmer and releasing the heat to stored air that is cooler
How well a substance resists changing its temperature when it absorbs or releases heat
Specific heat
What is the relevance of waters high specific heat to life on earth
The water that covers much of earth keeps temperature fluctuations on land and in water within limits that permit life. Also because organisms are made primarily of water, they are better able to resist changes in their own temperature than if they were made if a liquid with a lower specific heat
What is evaporation
The transformation from a liquid to a gas
What effects does the high amount of energy required to vaporize water have ?
It helps moderate earths climate , plays a part in the formation , accounts for the severity of steam burns,
Explain the statement “it’s not the heat ;it’s the humidity “
High humidity on a hot day increases discomfort because the high concentration of water vapor in the air inhibits the evaporation of sweat from the body
How does compounds made up of non ionic polar molecules dissolve on water
Such compounds dissolve when water molecules surround each of the solute molecules an form hydrogen bonds with them
What would cause an aqueous solution to have an imbalance in H+ and OH- concentrations
When acids dissolve in water they donate additional H+ to the solution
How do bases reduce the H+ concentration directly
By accepting hydrogen ions
How do bases reduce H+ concentration indirectly
Dissociating to for hydroxide ions, which combine with hydrogen ions to form water
A solution with a higher concentration of OH- than H+
Basic solutions
Solution where the H+ and OH- concentrations are equal
Neutral
