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AP Biology > Chapter 2: The Nature of Molecules and the Properties of Water > Flashcards

Chapter 2: The Nature of Molecules and the Properties of Water Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Matter

A

any substance that has mass and occupies space

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2
Q

Mass

A

the amount of a substance

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3
Q

Atom

A

small particles that make up matter

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4
Q

Weight

A

the force gravity exerts on a substance

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5
Q

Atomic number

A

number of protons in an atom

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6
Q

Atomic mass/weight

A

sum of the masses of its protons and neutrons

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7
Q

What are the masses of atoms and subatomic particles measured in?

A

Daltons

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8
Q

Cation

A

atom with more protons than electrons with net + charge

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9
Q

Anion

A

atom with less protons than electrons with net - charge

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10
Q

Ion

A
  • atoms where the number of protons is not the same as the number of electrons
  • gain or loss of electrons
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11
Q

Proton

A
  • positive
  • found in nucleus
  • 1 dalton
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12
Q

Neutron

A
  • neutral
  • found in nucleus
  • 1 dalton
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13
Q

Electron

A
  • negative
  • orbit nucleus in energy levels
  • negligible mass
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14
Q

Isotope

A

atoms of a single element with different number of neutrons
ex) Carbon-12 (stable) , Carbon-13 (stable) , Carbon-14 (radioactive) - used to determine ages of fossils

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15
Q

Radioactive decay

A

nucleus of an atom breaks up into elements with lower atomic numbers and releases energy

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16
Q

Orbital

A

regions where electrons are likely located

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17
Q

Energy levels

A
  • outer levels have more energy
  • 1st level with 1 orbital: holds 2 electrons
  • 2nd level with 4 orbitals: holds 8 electrons
  • 3rd level can hold 18 electrons
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18
Q

Chemical behavior

A
  • based on valence electrons
  • complete valence shell = nonreactive
  • incomplete valence shell = chemically reactive
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19
Q

Octet rule

A

atoms tend to establish completely full outer energy levels

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20
Q

Molecule

A
  • made up of two or more atoms of the same or different elements bonded together
  • ex) O2
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21
Q

Compound

A
  • two or more different elements bonded together
  • ex) H2O
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22
Q

What four elements make up 96% of living matter?

A

carbon, oxygen, hydrogen, and nitrogen

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23
Q

Periodic table trends

A
  • elements up and down have same number of electrons in outer shells
  • atoms are electrically neutral
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24
Q

Chemical bonds

A

join molecules together

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25
Q

Covalent bond

A
  • two atoms SHARE one or more pair of valence electrons
  • can be single (share a pair of electrons) , double (share two pairs of electrons) , or triple (share three pairs of electrons)
  • form stable molecules
  • strength increases with number of shared electrons
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26
Q

Ionic bond

A
  • electrons are TRANSFERRED from one atom to another
  • attraction of opposite charges
  • form crystals
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27
Q

Hydrogen bond

A
  • weak attraction between molecules or parts of the same molecule
  • slightly positive hydrogen in one molecule attracted to slightly negative atom in another molecule
  • responsible for emergent properties of water
  • ex) electrons spend more time orbiting oxygen than hydrogens, so oxygen becomes slightly negative
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28
Q

Van der Waals Interactions

A
  • attractions between every changing + and - “hot spots” in covalently bonded nonpolar molecules
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29
Q

Polar covalent bonds

A
  • unequal sharing of electrons
  • regions of partial negative charge near more electronegative region
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30
Q

Nonpolar covalent bonds

A
  • equal sharing of electrons
  • ex) methane
31
Q

Electronegativity

A
  • atoms differ in affinity for electrons
  • usually increases left to right across periodic table
  • usually decreases down the column of periodic table
32
Q

Oxidation

A

the loss of electrons (or loss of hydrogen atoms)

33
Q

Reduction

A

the gain of electrons (or gain of hydrogen atoms)

34
Q

Chemical reactions

A
  • make and break chemical bonds
  • many are reversible
  • matter is conserved
  • reactions must be balanced
35
Q

Equilibrium

A
  • rate of formation of products = rate of breakdown of products
  • no change in concentrations
36
Q

What does the shape of a molecule tell us?

A
  • molecules with similar shapes have similar functions
  • 2 atoms = linear shape
  • water is shaped like a V
37
Q

Catalyst

A

substance that increases reaction rate

38
Q

Cohesion

A
  • polarity of water which makes water molecules attracted to each other
  • ex) water droplets bead up
39
Q

Adhesive

A
  • polarity of water which makes it attracted to other polar molecules
  • ex) meniscus in graduated cylinder; wet microscope slides stick together
40
Q

Capillary action

A
  • liquid moves up through narrow tube
  • results from cohesion and adhesion
  • ex) water goes from roots to leaves; drinking straws; paper towel wicking
41
Q

Surface tension

A
  • caused by cohesion
  • allows insects to walk on water
42
Q

Density of water

A
  • ice is less dense than liquid water because hydrogen bonds keep the molecules further apart
  • ex) lakes freezing from top down
43
Q

Kinetic energy

A

energy of motion

44
Q

Heat

A

total amount of energy in a system

45
Q

Temperature

A

average amount of kinetic energy in molecules

46
Q

Calorie

A

amount of heat required to raise temp of water by 1 degree Celsius

47
Q

Specific heat

A
  • amount of heat a substance needs for a given increase of temperature
  • water has a high specific heat
  • hydrogen bonds absorb heat when they break, release it when they form
  • takes a lot of energy to raise 1 g of water 1 degree C because hydrogen bonds need to break
  • heats up slowly and retains heat for longer
  • can absorb lots of heat, but with minimal temperature changes
  • allows for homeostasis
48
Q

How are specific heat and polarity related?

A

more polar = higher specific heat

49
Q

High Heat of Vaporization

A
  • takes a lot of energy to convert liquid water to vapor
  • many bonds must be broken for water to evaporate
  • ex) used by organisms when sweating to cool off
50
Q

Hydrophobic

A
  • nonpolar covalent molecules
  • water fearing, don’t dissolve in water
  • ex) fats, oils
51
Q

Hydrophilic

A
  • polar covalent molecules
  • water loving
  • form hydrogem bonds with water
52
Q

Amphipathic

A
  • molecules with polar and nonpolar regions
  • ex) phospholipids: polar head/nonpolar tail
53
Q

Mole

A

weight of a substance in grams that relates to the atomic masses of all the atoms in a molecule of the substance

54
Q

Ionization

A

covalent bonds within water may break and form ions

55
Q

pH

A
  • measures the degree of acidity
  • measures hydrogen ion concentration of a solution
  • water pH = 7 = neutral
56
Q

Difference on pH scale

A

pH 2 has 1000 times more H+ ions than pH 5

57
Q

Acid

A
  • substance that causes an increase in H+ ions
  • pH is less than 7
58
Q

Base (alkaline)

A
  • substance that causes increase in OH- ions
  • pH is more than 7
59
Q

Buffer

A
  • substance that resists changes in pH
  • can donate H+ to solutions or remove them
  • maintain homeostasis
60
Q

Bicarbonate Buffer System

A
  • HCO3- = bicarbonate (weak base)
  • H2CO3 = carbonic acid (weak acid)
  • helps to balance blood pH
61
Q

Does CO2 increase or decrease pH?

A

decrease, becomes more acidic

62
Q

Acidosis and its solution

A
  • when the blood pH becomes more acidic and can harm kidneys
  • solution: patients are given HCO3- to increase pH and decrease H+
63
Q

How many of the 90 naturally occurring elements on Earth are found in living systems?

A

12

64
Q

Why are the noble gases more stable than other elements of the periodic table?

A

all eight electrons fill up their outer energy level, so they are inert (nonreactive)

65
Q

List the bonds in order form weakest to strongest

A

van der Waals, hydrogen bonds, ionic bonds, covalent bonds

66
Q

What factors influence the extent of chemical reactions

A

1.) Temperature - it increases the reaction rate because the reactants bump into each other at greater frequency
2.) Concentration of reactants and products - more reactants speed up reactions, BUT more products slows down reaction unless it is reversible
3.) Catalysts - speed up reactions; example is enzyme

67
Q

How much of the body is composed of water?

A

2/3

68
Q

What is water’s polarity and bonding like?

A
  • neutral in charge and polar covalent
  • covalent bonds between hydrogen and oxygen atoms result in uneven sharing of electrons
  • polar because hydrogen atoms are slightly positive, while oxygen area is slightly negative
69
Q

Polar molecules

A
  • molecule has uneven pattern of electric charge
  • results in hydrogen bonding between water molecules
  • responsible for emergent properties of water
70
Q

Why is water a “universal” solvent?

A
  • dissolves many polar substances
  • separates ionic substances into ions
  • provides medium for molecules to interact
71
Q

What substances dissolve in water?

A
  • ionic substances, which dissolve into ions
  • polar covalent substances
72
Q

Solution

A

uniform mixture of molecules of 2 or more substances

73
Q

Solvent

A

substance present in the greatest amount

74
Q

Solute

A

substance present in lesser amounts

AP Biology (5 decks)

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