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Water makes up __% to __% of the cell content of living organisms

70-95%

Water covers what percentage of the Earth's surface?

75%

Water's unique properties allows for ___ in general

life

hydrogen bonding between water molecules creates a ___ liquid w/ ______ specific heat and _____ heat of vaporization.

hydrogen bonding between POLAR water molecules create a cohesive liquid w/ HIGH specific heat and HIGH heat of vaporization

what does water's high specific heat and high heat of vap help to regulate?

helps regulate environmental temperature

ice and does what for oceans and lakes?

ice FLOATS and protects oceans and lakes from freezing

what aspect of water makes it a versatile solvent (btw often called "universal" but that's just cuz it can dissolve a lotta shit)

its polarity

the [H+] (concentration of H+) or pH determines what abt a solution?

whether its acidic, neutral, or basic

what do buffers do

regulate an organism's pH

what bonds in water result in hydrogen bonding?

polar covalent bonds

most electronegative is where on periodic table

top right (not including noble gases)

polar covalent vs nonpolar covalent

polar = shared unequally
nonpolar = shared equally (or like super close)

-> so oxygen is more EN than hydrogen (need to know for this unit)

polar covalent vs nonpolar covalent

polar = shared unequally

nonpolar = shared equally (or like super close)

What are the partial charges of H and O in H₂0

H has a δ+

O has a δ-

(δ = partial btw)

cohesive =

when water sticks to itself

adhesive =

when water sticks to other shit

why is liquid water so cohesive?

due to the constant forming and reforming of hydrogen bonds which hold the molecules close together

what allows for water to be pulled upward in plants? what else contributes to water transport?

cohesion

adhesion

(also, these two combined is what allows for capillary action)

hydrogen bonding between water molecules produce ___ ___ at the interface of water and air which in turn makes it unusually hard to break

SO HYDROGEN BONDING = _ ???

HIGH SURFACE TENSION

energy is the energy associated w/ all the random movements of atoms and molecules

thermal energy = kinetic energy

temperature measures/reflects what

the average kinetic energy of molecules

thermal energy reflects what

the TOTAL kinetic energy

the thermal energy that transfers smth to smth is defined as _

….smth WARMER to smth COLDER is defined as HEAT

calorie =

amt of heat it takes to raise 1g of water by 1°C

___ calories = 1 kcal / Calorie (w/ a capital C)

1000 calories

1 kcal =

the amt of heat required to change the temp of 1 kg of water by 1°C

1 calorie = ___ joules

1 calorie = 4.184 joules

specific heat =

the amt of heat required to raise the temp of smth by 1 C

What is water's specific heat? which is…?

4.184 J/g*°C

which is high compared to other common substances

heat needs to be to break hydrogen bonds

absorbed

heat is when forming hydrogen bonds

released

high proportions of water in the environment and within organisms allows for

life.

it keeps temp fluctuations within the limits that permit life

occurs when molecules of a liquid w/ enough kinetic energy overcome their attraction to other molecules and escape into the air as gas (vapor)

vaporization or evaporation occurs

heat of vaporization =

amount of heat needed for 1g of a liquid to become a gas

water has a _ heat of vap?

high (cuz it takes a lot of heat to break hydrogen bonds holding the water together)

how does water help Earth moderate its climate?

solar heat absorbed by sea and then later released back

as liquid vaporizes, surface behind kinetic energy of escaping molecules and _ __

as liquid vaporizes, surface behind LOSES kinetic energy of escaping molecules and COOLS DOWN

evaporative cooling:

helps protect organisms from overheating and helps w/ stability of temps in lakes and ponds

as water cools below 4°C, it because?

expands because its molecules are moving too slowly to break hydrogen bonds

by 0°C, the water molecules are….

rigidly hydrogen bonded to four other molecules in a crystalline lattice that spaces the molecules farther apart than how it is for liquid water

water molecules are more _ _ when frozen as opposed to liquid

spaced apart

ice is less than liquid water, allowing for it to

less dense, allowing for it to float

when ice freezes and floats, what happens to the water beneath?

insulates the water there, potentially protecting organisms below the ice's surface

a solution =

homogeneous mixture of 2 or more substances

solvent =

thing doing dissolving

solute =

thing being dissolved

how does water dissolve shit?

positively and negatively charged regions of water attract to opposite regions of polar molecules -> solute molecules then become surrounded by the water molecules (a hydration shell) and dissolve into solution

what is it called when smth a surrounded by water molecules?

a hydration shell

ionic and polar substances are _?

hydrophilic - due to electrical attractions and hydrogen bonding

nonpolar and nonionic substances are __?

hydrophobic, won't mix easily or dissolve in water

REMEMBER - LIKE DISSOLVES ____?

like dissolves like

1 mol = (idek why this was included)

6.02 * 10²³ = avogadros number

molarity =

of moles of a solute dissolved in 1 liter of solution

water is a _ in an aqueous solution

solvent

brackets [ ] indicate what

molar concentration

increase [H+] =

decrease [OH-] (and vice versa)

more acidic = pH

more basic = pH

neutral = pH of

lower

higher

pH of 7

difference between each number on the pH scale (1 to 2) is a ____ difference

tenfold difference

buffers maintain a stable pH by…?

…accepting excess H+ or donating H+ when H+ concentration decreases

note: "weak acid-base pairs that reversibly bind hydrogen ions are typical of most buffering systems"

what free ions don't exist in aqueous solution

free hydrogen ions

why is water's pH 7 normally?

[ ] of H+ and OH- are the same

a water molecule can dissociate into a ___ ion ( ), and a __ ion ( )

a water molecule can dissociate into a hydrogen ion (H+), and a hydroxide ion (OH-)

when acids or bases dissolve in water, what shifts?

H+ and OH- balance shifts, changing pH

acid adds ____ while base reduces _____

H+ in a solution

what happens to a strong acid/base when mixed with water

it dissociates completely

what happens to a weak acid/base when mixed with water

partially dissociates

[H+] * [OH-] =

[H+] * [OH-] = 1 * 10⁻¹⁴

fossil fuels release what into the atmosphere ?

CO2 (obviously lmao)

the ocean absorbs how much of the CO2, which leads to what?

25%, which lowers the pH of seawater, resulting in OCEAN ACIDIFICATION

• reduces [CO3^2-], which coral reefs need

pH = (formula)

pH = -log [H+]