Biol 1201: C3

Water & Chemical Context of life

What types of bonds are weak?

Hydrogen bonds

Why can ice float in water?

the water molecules are bonded farther apart, making it less dense

Whats unique about water?

Its the only common substance to exist naturally in all three states.

Where do electrons spend more time near on water?

oxygen(negative)

Is water polar or nonpolar?

polar(unequally distributed charge)

What does polarity allow?

water to form hydrogen bonds with each other

Four of waters properties that facilitate an environment for life are?

Cohesive behavior, Ability to moderate temperature, expansion upon freezing, versatility as a solvent

What holds water molecules together?

Hydrogen bonds(cohesion)

What does cohesion help?

Transport water against gravity in plants

What is adhesion?

attraction between different substances(ex/ water and plant cell walls)

When is heat absorbed?

When hydrogen bonds break

When is heat released?

when hydrogen bonds form

when does water reach its greatest density?

@ 4 C

what is an aqueous solution?

a solution where water is the solvent

What substances are hydrophilic?

ionic and polar substances

What substances are hydrophobic?

lipids and hydrocarbons

what is molecular mass?

masses of all atoms in a molecule

how many daltons=1 g?

6e13(avogadros #)

What is molarity?

number of moles or grams of solute per liter of solution(concentration)

In pure water what are the concentrations of H+ and OH-?

they are equal

what is an acid?

a substance that increases H+ concentration

What is an OH-

A substance that reduces the H+ concentration

what is ph define as?

ph=-log[H+]