Chemistry and Water Flashcards
how many elements did chemists recognize?
92
how many essential elements do we have?
25
what are essential elements?
elements needed to be healthy and reproduce
what are the elements called that are required by an organism in minute quantities?
trace elements
what element is needed to maintain the thyroid gland?
I
what element is a component of hemoglobin?
Fe
what element prevents tooth enamel from being attacked by bacteria?
Fl
what is and what can hypothyroidism lead to?
iodine deficiency; goiter
what royal queen of France had a goiter in the 1600s?
Marie de Médicis (wife of Henry IV)
how much would it cost to purchase the elements to make an adult human?
$118.63
what is an example of a naturally occurring element that is toxic to organisms?
arsenic can cause cancers
what are isotopes?
have more neutrons than other atoms of the same element and hence, a greater mass
what is an unstable carbon isotope?
C-14 in that the nucleus decays spontaneously giving off particles and energy as it decays into N-14; beta decay
half life of C-14?
5,730 years
what are isotopes used for? (2)
determine age of fossils through radioactive tracers
treat cancer through radioactive therapy
another use of radioactive tracers?
spies for medical diagnosis- test for GERD (gastroesophageal reflux disease) in newborns who spit up they drink radioactive barium Ba)
what type of energy do electrons have? based on what?
potential energy based on their position relative to the nucleus of an atom
relationship between potential energy of an electrons and its position relative to the nucleus?
electrons near the nucleus have low potential energy by can be excited to a higher energy level as they gain energy
what happens when an electron returns to a lower level?
energy is lost in the form of light or heat
how to plants use the energy released from electrons?
harness the energy to produce C6H12O6
where on the staircase does the ball have the greatest potential energy?
top of the staircase
sunlight strikes the surface of a car exciting the electrons to higher energy levels. When they fall back to their original levels what happens?
the car surface feels hot
what happens when you bite into a Wint-O-Green Lifesaver in the dark?
produces a faint blue light
types of chemical bonding? (2)
valence electrons participate in molecule and compound bonding
molecule bonding
two or more atoms held by a covalent
H2, 02, H2O
compound bonding
a combination of two or more different elements
CH4, H2O
covalent bondiing
sharing a pair of valence electrons by two atoms; strong bond
H2, O2, H2O, CH4
Non-Polar Covalent bonding
type of covalent bond where the electronegativity is equal
O2, H2, CH4
Polar Covalent bonding
type of covalent bonding where one atom is more electronegative than the other atom
H2O, NH3
Ionic bonding
the attraction for valence electrons is so unequal between two atoms that the more electronegative atom strips an electron from its partner resulting in charged atoms: strong bong when dry, weak in H2O
NaCl, MgCl2
cation
positive charge
anion
negative charge
Hydrogen Bonding
attraction bw hydrogen and an electronegative atom; weak individually, but strong as a whole
FON
van der Waals
includes London dispersion forces and dipole-dipole forces. weak indivudally,strong as whole
London dispersion forces
nonpolar molecules with + and - charged regions where sometimes electrons accumulate in one area
dipole-dipole forces
bw polar molecules
what sets van der Waals and Hydrogen Bonding aside from the other types of bonding?
intermolecular forces
geckos can walk straight up walls because each toe has 100,000+ tiny hairs called setae and each setae top has multiple projections that interact with the wall molecules. what bond type allows for this?
van der Waals
how are most drugs manufactured to keep them stable, but allow them to easily dissociate in our bodies?
salts/ionic bonds
biomimicry
using nature to inspire product design
example of a correlation between the shape of a molecule and its function
sugars and mimics like artificial sweeteners both fit into taste bud receptors on our tongue and send a message to our brain via sensory neuron telling us we are eating something sweet
what flavors can our tastebuds (papillae) tatse? (5)
sweet, sour, salty, bitter, umami
does the tongue have specific regions for each diff tatse?
no- elongated taste cells that make up taste buds (located in papillae) have multiple receptors for the 5 flavors
how do biological molecules often bind if shapes are complimentary?
bind temporarily to each other by forming weak bonds
how do opiates relieve pain?
by binding weakly with specific receptors that natural endorphins use on the surface of brain cells
what are natural endorphins?
neurotransmitters made by the pituitary glands
structure and function is a major theme in biology?
true
what sweet food releases endorphins in the brain/ a natural analgesic (painkiller)?
chocolate + comfort food (carb heavy)
what do athlete’s experience after prolonged exercise and after “hitting the wall”
runner’s high - body releases endorphins to counter the pain
what are some ways to release endorphins from the brain?
smile, pet an animal, get a massage, be active, be in love, ect
true smile w eyes
Duchenne Smile
what type of molecule is water?
polar covalent molecule
why is water a polar covalent molecule?
O is more electronegative than H, so the electrons are pulled toward it resulting in a partial negative charge near O and partial positive charge near H
how many planets have we found outside our solar system?
5000
how many of the planets we discovered show evidence of water vapor?
2-3, maybe 1/3 are contendors
how many of the plants we found show evidence of water vapor?
2-3, but 1/3 are contenders
order of 8 planets in our solar system
mercury, venus, earth, mars, jupiter, saturn, uranus, neptune
has water been found in mars?
yes, ice caps at both poles and ice is under mar’s surface
how much of water are humans comprised of? some animals?
> 60%; 95% (jellies)
rules of 3
3 min wo o2
3 hr wo shelter/warmth
3 days wo water
3 weeks wo food
one water molecule is held together by what bond?
polar covalent bonds
what bond type holds one h2o molecule with another?
h bonds
how many hydrogen bonds form off from one h2o molecule?
4
what are the emergent properties of water due to?
h bonds`
cohesion
h bonds hold one h2o molecule to another
adhesion
h bonds hold one h2o molecule to other substances
surface tension
a measure of how difficult it is to stretch or break the surface of a liquid/water forms an invisible film due to h bonds
capillary action
water flows upwards in narrow tubes
in plants water moves through xylem, and sugars through phoelm
water specific heat?
high specific heat- hard to change temp
how can some insects/animals walk on water?
cohesion of water, adhesion of bank
heat and body of water relationship?
large bodies of water absorb and store a lot of heat from the sun during the day and only warm up a few degrees. in the night, the gradual cooling water warms the air
water is less dense as a what than as a liquid?
solid; water begins to freeze and forms a crystalline lattice and the ice floats and insulates the liquid water below
4C most dense
heat of vaporization of water
high- harder to evaporate
takes a lot of heat energy to vaporize water compared to other substances
helps moderate Earth’s climate
stabilizes temp in lakes/ponds
steam burn
water condenses into a liquid on the skin
evaporative cooling
liquid evaporates, the surface of the liquid that remains cools down/the “hottest” molecules with the creates kinetic energy left as a gas
evaporation of sweat cools a person
why does h2o dissolve NaCl?
ionic compounds have charges and water molecule is a polar molecule with partial charges. the attraction of opposite charges breaks NaCl to Na+ and Cl-
what is the sphere of water around each dissolved ion called?
hydration shells
dissolving agent of a solution
solvent
substance being dissolved
solute
what type of solvent is water? what did we use to call it?
versatile - dissolves many substances; universal
what can water dissolve? what can’t it?
ionic compounds (charge) and polar molecules (partial charge) even large proteins if they have polar/ionic regions; non polar (no charge) like lipids (oil)
what is the enzyme found in tears, sweat, and saliva
lysozyme
hydrophilic
substances with an affinity for water
cotton towel or paper towel made of cellulose fibers that have many polar regions
hydrophobic
substances that do not have an affinity for water
nonpolar covalent bonds in lipids
how does soap work?
soap (salts of fatty acids) and grease have a hydrophilic head and hydrophobic tails. their similar structures cause them to forma greasy soap ball called a micelle and stays dispersed in water
what temperature scale is used in biology?
celsius
when does water freeze? boil?
0C; 100C
human body average temp? in farenheit?
37C; 98.2 F
room temperature avg temp?
22C
reaction between 2 water molecules
2 H2O <-> H3O+(H+) + OH-
what does water dissociate into?
hydronium ion and a hydroxide ion
how are the concentrations of H+ and OH- in pure water?
equal
what does an acid do to the concentration of a solution?
increase [H+] and removes OH- from a solution
what does a base do in a solution?
accepts H+ or reduced [H+] by forming OH- (has more OH- than H+)
product of concentrations of H+ and OH- in aq solution
10^-14M
H+ and OH- concentrations vary by a factor of what? what is it expressed by?
100 trillion+; logarithms
how to find pH of a solution?
-log of [H+]
concentrations of a neutral solution
[H+] = [0H-] =10^-7
if an acid has a pH of 3, what is [H+]? 13? [OH-]?
[H+]=10^-3 and [OH-] = 10^-11;
[H+]=10^-13 and [OH-] = 10^-1
if you go from a pH 2 to 6, how much of a difference is this?
10,000 x’s more basic
difference going from pH 8 to 6?
100 x’s more acidic
pH of most biological fluids? exception?
pH 6-8; stomach acid with pH of 2
pH of blood?
7.4 (slightly basic/alkaline)
how long can a person survive if pH drops to 7 or rises to 7.8?
no more than a few minutes
what chemical system in the blood maintains a stable pH?
CO2 + H2O<-> H2CO3 <-> HCO3- + H+
what does bicarbonate do in the blood?
buffers the blood’s plasma bc it’s basic
what does the hydrogen ion do in the blood?
binds w/ hemoglobin to prevent plasma from becoming acidic
what is a buffer?
a substance that minimizes changes to pH despite the addition of acids or bases
what is the reaction that occurs when CO2 is absorbed in seawater?
CO2+ H2O<-> H2CO3 <-> HCO3- + H+
what happens when CO2 is absorbed by water?
ocean acidification - lowering of ocean’s pH
how much will the ocean’s pH drop by the end of the century? how do we know?
0.3-0.5 pH units - based on CO2 levels in air bubbles trapped in ice
how are the pH levels now compared to the past 420,000 years?
.1 pH unit lower
what is the calcification process? who is it used by?
formation of calcium carbonate
Ca+2 + CO3-2 -> CaCo3
corals, animals that build shells
why is there a decrease in carbonate ions? what is the effect of this?
free floating hydrogen ions bond with them (H+ + CO3-2-> H2CO3)
less carbonate ions for calcification, leaving crustaceans w/o calcium carbonate, reducing in numbers
