ap bio 2a2b typee!

what is electronegativity?

how strongly an atom attracts shared electrons.

what does a higher electronegativity indicate?

a stronger pull on electrons.

what is a covalent bond?

when atoms share electrons.

what characterizes nonpolar covalent bonds?

equal sharing of electrons between atoms with similar electronegativities.

what characterizes polar covalent bonds?

unequal sharing of electrons, resulting in partial charges.

what is an ionic bond?

formed when electrons are transferred from one atom to another.

what happens when an atom loses electrons?

it becomes a positive ion (+).

what happens when an atom gains electrons?

it becomes a negative ion (-).

what is the order of bond strength from strongest to weakest?

ionic bonds → covalent bonds → hydrogen bonds → van der waals interactions.

what defines a hydrogen bond?

a weak attraction between a partially positive hydrogen and a partially negative atom.

what is an example of van der waals interactions?

geckos sticking to walls.

what are reactants in a chemical reaction?

substances you start with in a chemical reaction.

what are products in a chemical reaction?

substances made by the reaction.

what is the general format of a chemical reaction?

reactants → products.

what is the photosynthesis equation?

6co₂ + 6h₂o → c₆h₁₂o₆ + 6o₂.

what does chemical equilibrium mean?

when the forward and reverse reactions happen at the same rate.

why is water considered polar?

oxygen attracts electrons more strongly than hydrogen.

what charge does oxygen acquire in water?

slightly negative (δ-).

what charge do hydrogens acquire in water?

slightly positive (δ+).

how do water molecules hydrogen bond?

the δ+ hydrogen of one water molecule is attracted to the δ- oxygen of another.

how many hydrogen bonds can one water molecule form?

up to 4 hydrogen bonds.

what is cohesion?

when water molecules stick to other water molecules.

what is adhesion?

when water sticks to different substances.

what does surface tension refer to in water?

the resistance of water's surface to being broken.

what causes water's surface tension?

cohesion and hydrogen bonding in water.

what is specific heat?

the amount of energy needed to change a substance's temperature.

why does water have a high specific heat?

hydrogen bonds absorb energy.

what are the implications of high specific heat for life?

helps organisms maintain stable temperatures and ecosystems avoid extreme changes.

why does ice float?

it is less dense than liquid water.

why is the floating ice important?

it forms an insulating layer, preventing entire bodies of water from freezing.

what is a solvent?

the substance that does the dissolving.

what is a solute?

the substance being dissolved.

what is a solution?

a uniform mixture of a solute and a solvent.

why is water a good solvent?

it is polar and can attract and surround ions and polar molecules.

what does hydrophilic mean?

water-loving; interacts well with water.

what does hydrophobic mean?

water-fearing; does not mix well with water.

why doesn't oil dissolve in water?

it is nonpolar and cannot form favorable interactions with polar water.

what does 'like dissolves like' mean?

polar substances dissolve in polar solvents and nonpolar substances in nonpolar solvents.

what is a hydrogen ion?

a positively charged ion (h⁺) formed when an acid donates a proton.

what defines an acid?

increases the concentration of hydrogen ions (h⁺).

what defines a base?

decreases the concentration of hydrogen ions (h⁺) or increases hydroxide ions (oh⁻).

what is a buffer?

resists changes in ph by absorbing excess h⁺ or releasing h⁺ when needed.

what happens to blood ph during exercise?

increased co₂ production leads to more h⁺ and a lower ph, but the buffer system helps limit ph changes.

how do covalent bonds differ from ionic bonds?

covalent bonds share electrons, while ionic bonds transfer electrons.

how do polar covalent bonds differ from nonpolar covalent bonds?

polar covalent bonds involve unequal sharing, while nonpolar covalent bonds involve equal sharing.

how do cohesion and adhesion differ?

cohesion is attraction between identical molecules, while adhesion is attraction between different molecules.

what is the difference between hydrophilic and hydrophobic?

hydrophilic substances interact with water, while hydrophobic substances avoid water.

what is the difference between an acid and a base?

acids increase h⁺ concentration, while bases decrease h⁺ concentration.

what is the difference between solvent and solute?

a solvent does the dissolving, while a solute gets dissolved.