Chp 2 & 3 Chemistry and Molecules of Life Flashcards
What are the two polarnegative elements?
Oxygen and Nitrogen
What are two most common non polar elements?
Carbon and Hydrogen
Is CH polar?
No
Is H2O polar
Yes, mucho polar
Which macromolecules and molecules in general are hydrophobic?
Lipids especially, non polar bonds
Which compounds are hydrophilic?
Ones with polar bonds.
Ultimately, all the properties of organisms depend on ?
how atoms are arranged in molecules. how molecules are arranged in cells
What is a compound?
A substance containing 2 or more elements in a fixed ratio
What is an isotope?
Two atoms of an element thar differ in number of neutrons
How is the atomic number determined?
number of protons in the nucleus
How is atomic mass determined?
Number of protons and neutrons in atom
What are valence electrons? What do they affect?
electrons on the outer most shell. They determine how the atom behaves (low/high energy)
What is the valence of an element? What does this correspond to?
The number of electrons necessary to complete the outer shell. corresponds to the number of covalent bonds an element can form
How many bonds can hydrogen form?
One
What is a covalent bond?
they share electrons
what is an ionic bond?
atoms strip electrons from bonding partners to stabilize both
How does water affect ionic bonds?
It attracts the polarly charged atoms and disolves the compound.
How is H2O charged?
Neutrally, but part is partially positively charged and part is partially negatively charged
Four emergent properties of water contribute to its ability to support life on Earth. What are they?
Cohesive behavior
ability to moderate temperature
expansion upon freezing
versatility as a solvent
Explain waters ability to be cohesive.
What is cohesion? How does it benefit earthlings?
Cohesion= tendency of molecules to stick together (hydrogen bonds)
- its benefits plants by helping water move against gravity when being delivered through plants
- helps in tear drainage
- surface tension
Explain waters ability to moderate temperature. How does this impact earth and earthlings?
water can release or absorb a large amount of heat with only a slight change in temperature.
its good for eathlings because we are composed of water and so when its hot out we dont brun to death because it takes so much heat for water to change temperature
Heat vs temperature
Heat: Measure of total kinetic energy to molecular motion.
Temperature: measures heat due to average kinetic energy of molecules
Why does it take so long for water to heat up?
heat energy is used to break hydrogen bonds before it can begin making the molecules move fast enough
why do ice cubes float in water?
Hydrogen bonds are more ordered when solid
why is water expanding upon freezing important?
if ice sank, all bodies of water would eventually freeze solid
what is a solvent
dissolving agent of a solution
high or low ph donate H+
acid
which ph accepts H+ ions?
bases
what is a hydrocarbon?
a compound consisting only of carbons and hydrogens
What is an isomer?
Same molecular formula but different structures and properties
