Ch02 Chemistry Flashcards
pure substance that contains only one kind of atom
element
Which elements make up about 96% of all living matter?
CarbonHydrogenNitrogenOxygen
What determines how atoms with behave, and whether they will form bonds?
the electrons in the atom’s valence shell
Bonds that form when atoms gain or lose one or more electrons to achieve stability.
ionic bonds
The strong bonds that form when atoms share electrons.
covalent
Groups of atoms that give important properties to biological molecules.
Functional Groups
electrically charged particle that forms when an atom gains or loses one or more elections
ion(cations + charged)(anions - charged)
the attractive force that an atomic nucleus exerts on electrons in a covalent bond
electronegativity
if two atoms are close to each other in electronegativity, they will form what type of bond?
nonpolar covalent bond
when electrons are drawn to one nucleus more than the other, they will form what type of bond?
polar covalent bond
What explains the fact that water molecules are “sticky?”
Hydrogen Bonding(+H is attracted to -O)
Water characteristic explained by Hydrogen bonding between water molecules.
Cohesion(water is “sticky”)(explains “surface tension”)
Water characteristic explained by Hydrogen bonding between water molecules and other substances.
Adhesion(explains capillary action in plants)(meniscus in graduate cylinder)(water “climbs” up paper towel)
Explain why water makes an excellent solvent.
PolarityWater is a polar molecule. Polar water molecules surround + and - ions (in Ionic compounds) as well as other polar molecules.
Substances that have an attraction to water
hydrophilic(polar molecules)
Substances that don’t have an attraction to water
hydrophobic(non-polar molecules)
Why does ice float?
Hydrogen bonding in ice becomes stable, causing water to become less dense than liquid water. (H bonds in liquid water are constantly breaking and reforming)
Water characteristic that resists changes in temperature.
High specific heat(water must absorb a lot of energy to break H bonds before it will change temperature!)
Water characteristic that explains the difficulty in changing liquid water into its gaseous form.
Heat of Vaporization(water must absorb a lot of energy to break H bonds - it absorbs this energy from its surroundings and thus has a cooling effect on its surroundings)
Describes how acidic or basic a solutions is
pH
H+ = OH-
neutral solution (pH = 7)
H+ > OH-
acidic solution(pH
H+
basic solution(pH > 7)
Why must the pH of living cells be about 7?
pH affects the shape of molecules - altered pH will affect the function of molecules and therefore affect cellular function
chemical reactions that build larger molecules from smaller molecules
dehydration synthesis(water taken out)(energy input)(anabolic reactions)
chemical reactions that split larger molecules into smaller molecules
hydrolysis(water input)(energy released)(catabolic reactions)
chemical reaction that require input of energy
endergonic (endothermic)(anabolic reactions)
chemical reaction that release energy stored in bonds
exergonic (exothermic)(catabolic reactions)
1st law of thermodynamics
energy is neither created nor destroyed(total energy before and after energy conversion in a reaction is the same)
2nd law of thermodynamics
disorder tends to increase(Entropy is increased)(some energy becomes unavailable for doing work)
measure of the disorder in a system
entropy
