Quiz Feb 13th Flashcards
What is polarity?
Differences in electronegativity within a molecule. One side of the molecule is partially negative the other is partially positive.
What are hydrogen bonds?
Weak interactions between the positive and negative areas of molecules. Water can form hydrogen bonds with water and other polar molecules
What is the difference between adhesion and cohesion?
Cohesion involves two of the SAME molecules forming hydrogen bonds with each other (water and water). Adhesion involves two DIFFERENT molecules forming hydrogen bonds with each other (amino acid and water)
How is water’s high surface tension important for life?
Plant life can rest on water’s surface without sinking, allowing for easier access to sunlight, which is necessary for photosynthesis
What is it important to life that water has a high solvency?
Humans are 60-70% water. Water’s high solvency means nutrients can be easily dissolved and transported through the human body
Why is it important to water that ice floats?
Aquatic organisms are able to live in freezing climates because ice floating on water’s surface provides an insulated layer of protection, which allows the organisms that live underneath to thrive.
Why is it important to life that water has a high heat capacity?
Aquatic organisms depend on water’s resistance to sudden temperature change to maintain appropriate regulation of their own body temperatures and homeostasis
Why is it important to life that water has capillary action?
Plants access water from the soil through their roots, capillary action is required for water to climb upwards and reach the roots of a plant.
What is capillary action?
Water’s cohesive and adhesive properties means that water molecules will bond to each other and to other polar molecules. This gives water the ability to “climb”
What are the three reasons living systems need a constant input of energy?
To grow, to reproduce, to maintain organization
What element is found in all classes of macromolecules?
Carbon
Nitrogen is found in which classes of macromolecules?
Proteins and nucleic acid
Carbon can be used to create what?
Carbon skeletons
What is a dependant variable?
Graph on y-axis. The variable which depends on a rule or law. What is being measured to determine the effect.
What is a independant variable?
Graph on the x-axis. What is being changed or manipulated. Impacts the dependant variable
What is standard deviation?
The amount a value deviates from the mean
What is mean?
Sum of the values divided by the number of values
What is standard error?
The variation between the calculated mean of the population and the one that is known or considered accurate
What is water?
Two atoms of hydrogen covalently bonded to an oxygen atom
What is the maximum number of hydrogen bonds water can make?
Four
How does polarity contribute to the other water properties?
Polarity -> hydrogen bonding -> cohesion + adhesion + solvency + high heat capacity
Cohesion -> surface tension
Cohesion + adhesion -> capillary action
What is water’s specific heat capacity so high?
At least a calorie needs to be absorbed to break hydrogen bonds. The change to the temperature of the water is relatively small because much of the heat is being used to disrupt the hydrogen bonds
Why does water have a high heat of vaporization?
The same reason it has a high specific heat capacity. Hydrogen bonds must be broken before a phase change can occur and much of the heat goes to breaking those bonds
Why is liquid water more dense than ice?
As water freezes, the molecules move too slowly to break the hydrogen bonds and spread out as a response
