CH2 Flashcards
(112 cards)
1
Q
Atom
A
Smaller identifiable unit of matter
2
Q
Electron orbital
A
a 3D space where an electron can be found 90% of the time
3
Q
Characteristics of weak bonds
A
- can come together, interact, and then separate
- transient & easily reversible
4
Q
chemical bond
A
forms when two atoms transfer or share outer electrons to complete their outer shells
5
Q
What 4 types of atoms make up 96% of all matter found in organisms today
A
Hydrogen
Carbon
Nitrogen
Oxygen
6
Q
A central theme in biology pertaining to structure
A
Structure affects function
7
Q
Elements
A
Substances that consist entirely of a single type of atom
8
Q
Mass number
A
Sum of protons and neutrons in an atom
9
Q
Dalton
A
Unit of mass approximately equal to the mass of one proton or one neutron
10
Q
Isotope
A
Any of several forms of an element that differ in the number of NEUTRONS contained in their nuclei
11
Q
Atomic weight
A
The average mass of an element that is based on the relative proportions of all its naturally occurring isotopes
12
Q
Radioactive isotope
A
Version of an element that has an unstable nucleus, releasing radiation energy as it decays to a more stable form. (Results in the radioisotope losing protons & becoming a different element)
13
Q
Orbital
A
The region of space around an atomic nucleus in which an electron is present most of the time
- grouped into electron shells
14
Q
Electron shell
A
Group of electron orbitals with similar energies
- electrons on outer shells hav more energy than those in inner shells
- electrons on outer most shell (valence shell) are often involved in chemical bonding
15
Q
Valence
A
Number of unpaired electrons in the outermost electron shell of an atom
- determines how many covalent bonds the atom can form
16
Q
Covalent bond
A
When 2 atoms share electrons
17
Q
Compound
A
Any substance that consists of more than 1 different type of element chemically bonded together
18
Q
Electronegativity
A
Measure of how strongly an atom pulls shared electrons toward itself in a bond
- Increases as you move along right of the periodic table
- Decreases as you move down the periodic table
19
Q
Factors that affect electronegativity
A
- Number of protons in the nucleus
- Distance between the nucleus and the valence shell
20
Q
Electronegative rank for 6 most abundant elements in organisms
A
O > N > S = C = H =
21
Q
Non polar covalent bond
A
Bond that involves EQUALLY shared electrons between two atoms of the same or similar electronegativity
22
Q
Polar covalent bond
A
A bond where there is an ASYMETRIC sharing of electrons between atoms differing in electronegativity
- Results in more electronegative atom having a partial negative charge and the other having a partial positive charge
23
Q
Ionic bond
A
Chemical bond formed when an electron is completely transferred from one atom to another
- Results in ions remaining associated due to their opposite electric charges
24
Q
Ion
A
Atom or molecule that has lost or gained electrons & thus carries a full electric charge
25
Cation
Positively charged ion
26
Anion
Negatively charged ion
- more electrons than protons
27
Methane
Most common molecule found in natural gas
28
Degree of tetrahedral structure
109.5
29
Planar (flat) structure degree
104.5
30
Molecular formulas
Notation that indicates only the numbers & types of atoms in a molecule
Ex; H2O
31
Structural formulas
2D notation that indicates the chemical symbols for the constituent atoms are joined by straight lines
32
Ball & stick models
3D notation in which covalent bonds are shown as rods/sticks connected in the correct geometry
33
Space-filling models
3D notation that depicts the relative sizes of atoms & their spatial relationships
34
Solvent
Any liquid in which one or more solids or gases can dissolve
35
Solute
Any substance that is dissolved in a liquid
36
Polar nature
1. Asymmetrical or unidirectional
2. Carrying a partial + charge on 1 side of a molecule & a partial - charge on the other
3. Generally hydrophilic
37
Hydrogen bond
A WEAK interaction btw 2 molecules or different parts of the same molecule resulting from the attraction btwn a HYDROGEN atom w/ a partial + charge & another atom with a partial - charge
38
Hydrophobic interactions
Very weak interactions btwn no polar molecules, or non polar regions of the same molecule, when exposed to an aqueous solvent
- surround water molecules support these interacts by interacting with one another and encapsulating the non polar molecules
39
Van Der Waals interactions
Weak electrical attraction btwn 2 non polar molecules or parts of a molecule that have been brought together, often through hydrophobic interactions
- In PROTEINS, it contributes to tertiary & quaternary structures
- occurs because of constant motion of electrons
- occurs between atoms of equal electronegativity
40
London dispersion force
Attraction that occurs when non polar molecules get extremely close to each other & the minute partial charge on 1 molecule induces an opposite partial charge in the nearby molecule
41
Cohesion
Tendency of SIMILAR molecules to cling together due to attractive forces
42
Adhesion
Tendency of certain DISSIMILAR molecules to cling together due to attractive forces
43
Surface tension
Cohesive force that causes molecules at the surface of a liquid to stick together, thereby resisting deformation of the liquid’s surface and minimizing its surface area
44
Is water denser as a liquid or as a solid
Liquid
45
Why does ice float
The hydrogen bonds cause the water molecules to form a repeating lattice structure like a crystal.
- structure is open, allowing large amounts of space between molecules
- each molecule maintains 4 hydrogen bonds as water freezes
46
Specific heat
The amount of energy required to raise the temperature of 1 gram of a substance by 1C
47
Higher polarity = higher …
Energy it takes to change their temperature (higher specific heat)
48
Heat of vaporization
The energy required to change 1 gram of a substance from a liquid to gas
49
Key properties of water
1. Solvent for charged or polar compounds
2. Desserts as a liquid than as a solid
3. High specific heat
4. High heat of vaporization
50
Chemical reaction
Any process in which substances combine or are broken down into other substances
- involves making and/or breaking of chemical bonds
51
Chemical equilibrium
A dynamic but stable state of a reversible chemical reaction in which the forward reaction and reverse reactions proceed at the SAME RATE, so the concentrations or reactants and products remain CONSTANT
52
Acids
Any compound that gives up protons or accepts electrons during a chemical reaction or that releases hydrogen ions when dissolved in water
- Raise hydro I’m ion concentration of water
53
Bases
Any compound that acquires protons or gives up electrons during a chemical reaction or accepts hydrogen ions when dissolved in water
- lowers the hydro I’m ion concentration of water
54
Does water act like an acid or a base
It can act as both
- just a weak acid and base
55
Acid-base reaction
A chemical reaction that involves a transfer of protons
56
What occurs when you add an acid to a solution
Increase in concentration of protons
57
What occurs when you add a base to a solution
Lowers the concentration of protons
58
Mole
-6.022 x 10^23
- Mass of 1 mole of an atom is the same as its atomic weight expressed in grams
59
Molecular weight
Sum of the atomic weights of all the atoms in a molecule
- roughly, the total number of protons & neutrons in the molecule
60
Molarity
Number of moles of a solute present in 1 liter of solution
61
pH
Measure of the concentration of protons in a solution & thus of how acidic or basic the solution is
- pH = -log[H-]
62
Acid pH level
- proton concentration no larger than 1 x 10^-7
- pH < 7
- acidic molecules release protons into solution
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Base pH level
- Proton concentration less than 1 x 10^-7
- pH > 7
- basic molecules accept protons form solution
64
Buffers
A substance that, in solution, acts to MINIMIZE changes in the pH of that solution when acid or base is added
65
Are buffers mainly acids or bases
Weak acids
66
Environments in which chemical reactions could've occurred to produce more complex organic molecules on Earth
1. Atmosphere; where gases are ejected from volcanoes
2. Deep-sea hydrothermal vents; extremely hot rocks contact deep cracks in seafloor
67
Most common reaction from volcanoes results in the production of ...
Carbonic acid
68
System
Defined set of interacting chemical components under observation
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Endothermic
referring to a chemical reaction that absorbs heat
70
Exothermic
Referring to a chemical reaction that releases heat
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Energy
the capacity to do work or supply heat
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Potential energy
Energy STORED in matter as a result of its POSITION or the position of electrons that form chemical bonds between atoms
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Chemical energy
The potential energy stored in chemical bonds between atoms
- Amount depends on POSITION of E's shared in a covalent bond
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Are strong bonds long or short
short
75
Kinetic energy
The energy of motion
76
Thermal energy
The total kinetic energy of a system that includes the MOTION of matter & is measured as temperature
77
Temperature
A measurement of thermal energy present in an object or substance
- reflects how much the constituent matter is moving
- AVERAGE amount of kinetic energy for all molecules in a compound
78
Heat
Thermal energy that is transferred from an object at higher temperature to one at lower temperature
79
First Law of Thermodynamics
The principle of physics that energy is conserved in any process.
- It can transferred and converted into different forms, but it cannot be created or destroyed
80
What makes a chemical reaction spontaneous
If they are able to proceed on their own, without any continuous external influence (such as added energy)
- POTENTIAL energy stored in REACTANTS > potential energy stored in PRODUCTS
- rxn releases heat = EXOTHERMIC
81
What are the 2 factors that determine if a reaction will proceed spontaneously?
1. If the products have lower potential energy than the reactants
- Shared electrons in the products are held more tightly than those in the reactants
2. Product molecules are less ordered than the reactant molecules
82
Entropy
A quantitative measure of the amount of DISORDER of any system
- increases in the system when the products of a chemical reaction are less ordered than the reactant molecules
83
Second Law of Thermodynamics
The principle of physics that states that the ENTROPY of the universe or any closed system always INCREASES in spontaneous reactions
84
What two factors are used to figure out whether a reaction is spontaneous or not?
Potential energy and entropy
85
Who was chemical evolution first proposed by?
Alexander I. Oparin
86
Miller’s Spark-Discharge Experiment
A large flask representing the ATMOSPHERE contained methane (CH4), ammonia (NH3), and hydrogen (H2), all of which have high potential energy. Connected to it was a smaller flask that represented an ocean with liquid water. The results contained formaldehyde, hydrogen cyanide, & other several complex compounds. Concluded that chemical evolution occurs readily if simple molecules with high free energy are exposed to a source of kinetic energy
87
Organic compound
group of molecules that include at least 1 carbon atom
88
What is one of the primary components in gasoline?
Octane
89
What is the primary energy storage molecule for organisms
sugar glucose
90
What is the general function of carbon atoms in organic molecules?
To furnish as a skeleton that gives the molecule its overall shape
91
Where is the chemical behavior of organic compounds dictated?
Groups of H, N, O, P, or S atoms that are bounded to the carbon atoms in a specific way
92
Functional groups
Small group of atoms bonded together in a precise configuration & exhibiting particular chemical properties that it imparts to any organic molecule in which it occurs
- H-, N-, O-, P-, S- containing groups found in organic molecules
93
6 functional groups commonly attached to carbon atoms
amino, carboxyl, carbonyl, hydroxyl, phosphate, sulfhydryl
94
amino functional group
- Amine
- Acts as base (tends to attract a proton
- H3N-R
95
Carboxyl functional group
- Carboxylic acid
- Acts as an acid (Tends to lose a proton in solution)
- R-CO2
96
Carbonyl functional group
- Aldehydes & Ketones
- Aldehydes, especially, react with certain compounds to produce larger molecules
- Site of reactions that link molecules into larger, more complex organic compounds
- R1-CHO + H-R2
97
Phosphate functional group
- Organic phosphate
- R-PO4
- Molecules w/more than 1 phosphate linked together store large amounts of chemical energy
- Carry negative charges on two of their oxygen atoms
98
Sulfhydryl
- Thiol
- R-SH
- When present in proteins, can form disulfide (S-S) bonds to contribute to protein structure
99
What functional groups tend to attract/release a hydrogen ion (proton) when in a solution?
amino & carboxyl
100
Hydroxyl functional group
- Alcohol
- R-OH
- Highly polar, so makes compounds more soluble through hydrogen bonding w/H2O
- May also act as a weak acid & drop a proton
101
What to do when you encounter an organic molecule that is new to you
1. Examine the overall size & shape provided by the carbon framework
2. Identify the types of covalent bonds present based on the electronegativities of the atoms. use this to estimate the polarity of the molecule & the amount of potential energy stored in its chemical bonds
3. Locate any functional groups & note the properties these groups give to the molecule
102
Macromolecule
Generally, any large organic molecule made up of smaller molecules (monomers) joined together er into a polymer
- Proteins, nucleic acids, polysaccharides
103
Monomer
Small molecule that can covalently bind to other similar molecule to form a larger macromolecule
104
Polymer
Any large molecule composed of small repeating units (monomers) bonded together
- Proteins, nucleic acids, polysaccharides
105
Theory of Chemical Evolution
Monomers polymerized to form the larger & more complex macromolecules that are now found in organisms
106
How do monomers polymerize
Thorugh condensation reactions aka dehydration reactions
107
Condensation reaction
Chemical reaction in which 2 molecules ar joined covalently with the removal of an -OH from one & an -H form another to form water
- Dehydration reaction
108
Hydrolysis
A chemical reaction in which a molecule is split into smaller molecules by reacting with water
- DOminates bc it both increases entropy & is favorable energetically
- Most involve splitting of polymers into monomers
109
Electronegativity
An atom's attraction of shared e's in a covalent bond
110
Low potential energy
E's are close to protons of 1 nucleus
- E's don't have far to fall toward the most positively charged nucleus
111
High potential energy
E's are far form protons of both nuclei, i.e. e's are shared equally between the 2 atoms
- E's have farther to fall because equidistant from + charge
112
The reactivity of an atom arises from...
the existence of unpaired electrons in the valence shell
