Chemistry and Water Flashcards

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1
Q

how many elements did chemists recognize?

A

92

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2
Q

how many essential elements do we have?

A

25

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3
Q

what are essential elements?

A

elements needed to be healthy and reproduce

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4
Q

what are the elements called that are required by an organism in minute quantities?

A

trace elements

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5
Q

what element is needed to maintain the thyroid gland?

A

I

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6
Q

what element is a component of hemoglobin?

A

Fe

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7
Q

what element prevents tooth enamel from being attacked by bacteria?

A

Fl

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8
Q

what is and what can hypothyroidism lead to?

A

iodine deficiency; goiter

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9
Q

what royal queen of France had a goiter in the 1600s?

A

Marie de Médicis (wife of Henry IV)

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10
Q

how much would it cost to purchase the elements to make an adult human?

A

$118.63

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11
Q

what is an example of a naturally occurring element that is toxic to organisms?

A

arsenic can cause cancers

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12
Q

what are isotopes?

A

have more neutrons than other atoms of the same element and hence, a greater mass

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13
Q

what is an unstable carbon isotope?

A

C-14 in that the nucleus decays spontaneously giving off particles and energy as it decays into N-14; beta decay

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14
Q

half life of C-14?

A

5,730 years

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15
Q

what are isotopes used for? (2)

A

determine age of fossils through radioactive tracers
treat cancer through radioactive therapy

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16
Q

another use of radioactive tracers?

A

spies for medical diagnosis- test for GERD (gastroesophageal reflux disease) in newborns who spit up they drink radioactive barium Ba)

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17
Q

what type of energy do electrons have? based on what?

A

potential energy based on their position relative to the nucleus of an atom

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18
Q

relationship between potential energy of an electrons and its position relative to the nucleus?

A

electrons near the nucleus have low potential energy by can be excited to a higher energy level as they gain energy

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19
Q

what happens when an electron returns to a lower level?

A

energy is lost in the form of light or heat

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20
Q

how to plants use the energy released from electrons?

A

harness the energy to produce C6H12O6

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21
Q

where on the staircase does the ball have the greatest potential energy?

A

top of the staircase

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22
Q

sunlight strikes the surface of a car exciting the electrons to higher energy levels. When they fall back to their original levels what happens?

A

the car surface feels hot

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23
Q

what happens when you bite into a Wint-O-Green Lifesaver in the dark?

A

produces a faint blue light

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24
Q

types of chemical bonding? (2)

A

valence electrons participate in molecule and compound bonding

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25
Q

molecule bonding

A

two or more atoms held by a covalent
H2, 02, H2O

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26
Q

compound bonding

A

a combination of two or more different elements
CH4, H2O

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27
Q

covalent bondiing

A

sharing a pair of valence electrons by two atoms; strong bond
H2, O2, H2O, CH4

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28
Q

Non-Polar Covalent bonding

A

type of covalent bond where the electronegativity is equal
O2, H2, CH4

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29
Q

Polar Covalent bonding

A

type of covalent bonding where one atom is more electronegative than the other atom
H2O, NH3

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30
Q

Ionic bonding

A

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

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31
Q

cation

A

positive charge

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32
Q

anion

A

negative charge

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33
Q

Hydrogen Bonding

A

attraction bw hydrogen and an electronegative atom; weak individually, but strong as a whole
FON

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34
Q

van der Waals

A

includes London dispersion forces and dipole-dipole forces. weak indivudally,strong as whole

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35
Q

London dispersion forces

A

nonpolar molecules with + and - charged regions where sometimes electrons accumulate in one area

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36
Q

dipole-dipole forces

A

bw polar molecules

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37
Q

what sets van der Waals and Hydrogen Bonding aside from the other types of bonding?

A

intermolecular forces

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38
Q

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?

A

van der Waals

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39
Q

how are most drugs manufactured to keep them stable, but allow them to easily dissociate in our bodies?

A

salts/ionic bonds

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40
Q

biomimicry

A

using nature to inspire product design

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41
Q

example of a correlation between the shape of a molecule and its function

A

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

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42
Q

what flavors can our tastebuds (papillae) tatse? (5)

A

sweet, sour, salty, bitter, umami

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43
Q

does the tongue have specific regions for each diff tatse?

A

no- elongated taste cells that make up taste buds (located in papillae) have multiple receptors for the 5 flavors

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44
Q

how do biological molecules often bind if shapes are complimentary?

A

bind temporarily to each other by forming weak bonds

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45
Q

how do opiates relieve pain?

A

by binding weakly with specific receptors that natural endorphins use on the surface of brain cells

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46
Q

what are natural endorphins?

A

neurotransmitters made by the pituitary glands

47
Q

structure and function is a major theme in biology?

A

true

48
Q

what sweet food releases endorphins in the brain/ a natural analgesic (painkiller)?

A

chocolate + comfort food (carb heavy)

49
Q

what do athlete’s experience after prolonged exercise and after “hitting the wall”

A

runner’s high - body releases endorphins to counter the pain

50
Q

what are some ways to release endorphins from the brain?

A

smile, pet an animal, get a massage, be active, be in love, ect

51
Q

true smile w eyes

A

Duchenne Smile

52
Q

what type of molecule is water?

A

polar covalent molecule

53
Q

why is water a polar covalent molecule?

A

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

54
Q

how many planets have we found outside our solar system?

A

5000

55
Q

how many of the planets we discovered show evidence of water vapor?

A

2-3, maybe 1/3 are contendors

56
Q

how many of the plants we found show evidence of water vapor?

A

2-3, but 1/3 are contenders

57
Q

order of 8 planets in our solar system

A

mercury, venus, earth, mars, jupiter, saturn, uranus, neptune

58
Q

has water been found in mars?

A

yes, ice caps at both poles and ice is under mar’s surface

59
Q

how much of water are humans comprised of? some animals?

A

> 60%; 95% (jellies)

60
Q

rules of 3

A

3 min wo o2
3 hr wo shelter/warmth
3 days wo water
3 weeks wo food

61
Q

one water molecule is held together by what bond?

A

polar covalent bonds

62
Q

what bond type holds one h2o molecule with another?

A

h bonds

63
Q

how many hydrogen bonds form off from one h2o molecule?

A

4

64
Q

what are the emergent properties of water due to?

A

h bonds`

65
Q

cohesion

A

h bonds hold one h2o molecule to another

66
Q

adhesion

A

h bonds hold one h2o molecule to other substances

67
Q

surface tension

A

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

68
Q

capillary action

A

water flows upwards in narrow tubes
in plants water moves through xylem, and sugars through phoelm

69
Q

water specific heat?

A

high specific heat- hard to change temp

70
Q

how can some insects/animals walk on water?

A

cohesion of water, adhesion of bank

71
Q

heat and body of water relationship?

A

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

72
Q

water is less dense as a what than as a liquid?

A

solid; water begins to freeze and forms a crystalline lattice and the ice floats and insulates the liquid water below
4C most dense

73
Q

heat of vaporization of water

A

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

74
Q

steam burn

A

water condenses into a liquid on the skin

75
Q

evaporative cooling

A

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

76
Q

why does h2o dissolve NaCl?

A

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-

77
Q

what is the sphere of water around each dissolved ion called?

A

hydration shells

78
Q

dissolving agent of a solution

A

solvent

79
Q

substance being dissolved

A

solute

80
Q

what type of solvent is water? what did we use to call it?

A

versatile - dissolves many substances; universal

81
Q

what can water dissolve? what can’t it?

A

ionic compounds (charge) and polar molecules (partial charge) even large proteins if they have polar/ionic regions; non polar (no charge) like lipids (oil)

82
Q

what is the enzyme found in tears, sweat, and saliva

A

lysozyme

83
Q

hydrophilic

A

substances with an affinity for water
cotton towel or paper towel made of cellulose fibers that have many polar regions

84
Q

hydrophobic

A

substances that do not have an affinity for water
nonpolar covalent bonds in lipids

85
Q

how does soap work?

A

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

86
Q

what temperature scale is used in biology?

A

celsius

87
Q

when does water freeze? boil?

A

0C; 100C

88
Q

human body average temp? in farenheit?

A

37C; 98.2 F

89
Q

room temperature avg temp?

A

22C

90
Q

reaction between 2 water molecules

A

2 H2O <-> H3O+(H+) + OH-

91
Q

what does water dissociate into?

A

hydronium ion and a hydroxide ion

92
Q

how are the concentrations of H+ and OH- in pure water?

A

equal

93
Q

what does an acid do to the concentration of a solution?

A

increase [H+] and removes OH- from a solution

94
Q

what does a base do in a solution?

A

accepts H+ or reduced [H+] by forming OH- (has more OH- than H+)

95
Q

product of concentrations of H+ and OH- in aq solution

A

10^-14M

96
Q

H+ and OH- concentrations vary by a factor of what? what is it expressed by?

A

100 trillion+; logarithms

97
Q

how to find pH of a solution?

A

-log of [H+]

98
Q

concentrations of a neutral solution

A

[H+] = [0H-] =10^-7

99
Q

if an acid has a pH of 3, what is [H+]? 13? [OH-]?

A

[H+]=10^-3 and [OH-] = 10^-11;
[H+]=10^-13 and [OH-] = 10^-1

100
Q

if you go from a pH 2 to 6, how much of a difference is this?

A

10,000 x’s more basic

101
Q

difference going from pH 8 to 6?

A

100 x’s more acidic

102
Q

pH of most biological fluids? exception?

A

pH 6-8; stomach acid with pH of 2

103
Q

pH of blood?

A

7.4 (slightly basic/alkaline)

104
Q

how long can a person survive if pH drops to 7 or rises to 7.8?

A

no more than a few minutes

105
Q

what chemical system in the blood maintains a stable pH?

A

CO2 + H2O<-> H2CO3 <-> HCO3- + H+

106
Q

what does bicarbonate do in the blood?

A

buffers the blood’s plasma bc it’s basic

107
Q

what does the hydrogen ion do in the blood?

A

binds w/ hemoglobin to prevent plasma from becoming acidic

108
Q

what is a buffer?

A

a substance that minimizes changes to pH despite the addition of acids or bases

109
Q

what is the reaction that occurs when CO2 is absorbed in seawater?

A

CO2+ H2O<-> H2CO3 <-> HCO3- + H+

110
Q

what happens when CO2 is absorbed by water?

A

ocean acidification - lowering of ocean’s pH

111
Q

how much will the ocean’s pH drop by the end of the century? how do we know?

A

0.3-0.5 pH units - based on CO2 levels in air bubbles trapped in ice

112
Q

how are the pH levels now compared to the past 420,000 years?

A

.1 pH unit lower

113
Q

what is the calcification process? who is it used by?

A

formation of calcium carbonate
Ca+2 + CO3-2 -> CaCo3
corals, animals that build shells

114
Q

why is there a decrease in carbonate ions? what is the effect of this?

A

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