Chemistry Flashcards
1
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Chemistry
A
The physical science that deals with the composition, properties, and changes in matter
2
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Observation
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A direct form of knowledge obtained by means of one of your five senses
3
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Qualitative observation
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Qualities of matter or changes in matter
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Quantitive observation
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Quantities of matter or the degree of change in matter
5
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Interpretation
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An indirect form of knowledge that builds on a concept or an experience to further describe or explain an observation
6
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Empirical knowledge
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Knowledge gained through observation
7
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Theoretical knowledge
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Explains and describes scientific observations in terms of ideas; not observable
8
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Graphs
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Visual presentations of observations
9
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Empirical hypotheses
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Preliminary generalizations that require further testing
10
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Empirical definitions
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Statements that define an object or a process in terms of observable properties
11
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Generalizations
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Statements that summarize a limited number of empirical results
12
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Scientific laws
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Statements of major concepts based on a large body of empirical knowledge
13
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The law of conservation of mass
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In any physical or chemical change, the total initial mass of reactant(s) is equal to the total final mass of product(s)
14
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Technology
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Skills, processes, and equipment required to manufacture useful products or perform useful tasks
15
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Science
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The study of the natural world with the goal of describing, explaining, and predicting substances and changes
16
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Homogeneous Mixtures
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Mixtures that contain pure substances evenly distributed throughout the mixture - Uniform, only one phase
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Heterogeneous Mixtures
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Mixtures that have an uneven distribution of pure substances - Non-uniform, may be more than one phase
18
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Element
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A simple pure substance that cannot be broken down into simpler substances by ordinary chemical means
19
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Matter
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Anything that has mass and occupies space
20
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Pure substances
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Composition is constant and uniform
21
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Mixtures
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Composition is variable and may or may not be uniform throughout the sample
22
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Entity
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A general term including particles (sub-atomic entities such as protons, electrons, neutrons), atoms, ions, molecules, and formula units.
23
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Atom
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Theoretically the smallest entity of an element that is still characteristic.
24
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Compounds
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Theoretically contain atoms of more than one element combined in a definite fixed proportion
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Chemical formula
Consists of element symbols representing the entities and their proportions present in the substance
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Who created a periodic table?
Dmitri Mendeleev, a Russian chemist
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Periodic law
Chemical and physical properties of elements repeat themselves in regular intervals, when the elements are arranged in order of increasing atomic number
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Family/Group of elements
Has similar chemical properties and includes the elements in a vertical column in the main part of the table
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Period
A horizontal row of elements whose properties gradually change from metallic to nonmetallic from left to right along the row
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Where are metals located on the periodic table?
To the left of the staircase line
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Where are non-metals located on the periodic table
To the right of the staircase line
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What are semi-metals (Metalloids) and where are they located on the periodic table?
A class of elements that are distributed along the staircase line
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IUPAC
International Union of Pure and Applied Chemistry
| A governing body for scientific communication and has defined a set of standard conditions
34
SATP
Standard Ambient Temperature and Pressure
| Under these ambient (surrounding) conditions, the materials are at a temperature of 25ºC and a pressure of 100kPa
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Properties of metals
Shiny, bendable, good conductors of heat and electricity
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Properties of nonmetals
Not shiny, not bendable, generally not good conductors of heat and electricity in their solid form
At SATP most nonmetals are gases and few are solids Solid nonmetals are brittle and lack lustre
Most nonmetals consist in compounds
37
Alkali metals
Group 1 elements. They are soft, silver-colored metals that react violently with water to form basic solutions. The most reactive alkali metals are cesium and francium
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Alkaline-earth metals
Group 2 elements. They are light-reactive metals that form oxide coatings when exposed to air
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Halogens
Elements in Group 17. They are all extremely reactive, with fluorine being the most reactive
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Noble Gases
Elements in Group 18. They are special because of their extremely low chemical reactivity
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Main Group Elements
The elements in Groups 1, 2, and 12 to 18. Of all the elements, the main group elements best follow the periodic law
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Transition elements
The elements in Groups 3 to 11. These elements exhibit a wide range of chemical and physical properties
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Lanthanoids
Elements with atomic numbers 58 to 71
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Rare earth elements
Include lanthanoids and yttrium and scandium
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Actinoids
Elements with atomic numbers 90 to 103
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Transuranic elements
The synthetic elements that have atomic numbers of 93 or greater (Beyond Uranium)
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Electronegativity
A number that describes the relative ability of an atom to attract a pair of bonding electrons in its valence level
48
Theoretical descriptions
Specific descriptive statements based on theories or models
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Theoretical hypotheses
Ideas that are untested or extremely tentative
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Theoretical Definitions
General statements that characterize the nature of a substance or process in terms of a non-observable idea
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Theories
Comprehensive sets of ideas based on general principles that explain a large number of observations
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Analogies
Comparisons that communicate an idea in more familiar or recognizable terms
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Models
Physical, graphic, or mental representations used to communicate an abstract idea
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What characteristics must a theory have in order to be accepted by the scientific community?
Must:
Describe observations in terms of non-observable ideas
Explain observations by means of ideas
Predict results in future experiments that have not yet been tried
Be as simple as possible in concept and application
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Mass number
The number of protons plus neutrons in their nucleus
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Atomic number
The characteristic number of protons in the nucleus of atoms of that element
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Ions
Have an electrical charge
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Monatomic ions
Single atoms that have gained or lost electrons
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Cations
Positively charged ions
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Negatively charged ion
Anions
61
Verified prediction
If the evidence agrees within reasonable experimental error with the prediction
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Falsified
If the evidence obviously contradicts the prediction
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What are three possible strategies concerning unacceptable theories?
Restrict - Treat the conflicting evidence as an exception and use the existing theory within a restricted range of situations
Revise - The new evidence becomes part of an improved theory (most common)
Replace - Replace the existing theory with a totally new concept.
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Ionic compounds
Metal-Nonmetal combinations
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Molecular compounds
Nonmetal-Nonmetal combinations
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Metal-Metal combinations
Alloys and inter-metallic compounds
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Diagnostic test
Laboratory procedure conducted to identify or classify chemicals
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Empirical definitions
A list of empirical properties that define a class of chemicals
69
Difference between Ionic compounds and Molecular compounds
At SATP:
Ionic solids
Molecular varied
When dissolved in water:
Ionic conducts
Molecular generally not
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Acids
Pure compounds at SATP that form conducting aqueous solutions that turn blue litmus paper red
Acids exhibit properties only when dissolved
Have properties of molecular compounds
Start with hydrogen or end in COOH
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Bases
Compounds whose aqueous solutions make red litmus paper turn blue
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Neutral
Compounds whose aqueous solutions do not affect litmus paper
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Multi-valent
More than one type of ion
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Polyatomic ions
Ions containing a group of atoms with a net positive or negative charge
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Formula unit
Of an ionic compound is a representation of the simplest whole number ratio of ions
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Empirical formula
The simplest ratio formula
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Molecule
Nonmetal atoms share electrons and the sharing holds the atoms together
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Molecular formula
Indicates the number of atoms of each kind in a molecule
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Water
H2O/HOH
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Hydrogen peroxide
H2O2
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Ammonia
NH3
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Glucose
C6H12O6
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Sucrose
C12H22O11
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Methane
CH4
85
Propane
C3H8
86
Octane
C8H18
87
Methanol
CH3OH
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Ethanol
C2H5OH
89
Hydrogen sulfide
H2S
90
Which perspective leads to researching and explaining natural phenomena?
Scientific
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Which perspective is concerned with the development and use of machines, instruments, and processes that have a social purpose?
Technological
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Which perspective considers relationships between living organisms and the environment?
Ecological
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Which perspective focuses on the production, distribution, and consumption of wealth?
Economical
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Which perspective involves governments, vote-getting actions or arguments based on ideology?
Political
95
Physical change
Fundamental entities remain the same
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Chemical change
Change in chemical bonding
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Nuclear change
Create entirely new atomic entities
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Kinetic molecular theory
Smallest entities of a substance are in continuous motion
99
Diagnostic test
Short, specific test with expected evidence to see if a substance is present
100
Avogadro's number
6.02 x 10^23
101
mol
Abbreviation for mole, one substance in the atomic quantity of Avogadro's number
102
Solution
Homogeneous mixture of a solute
103
Solute
A substance dissolved
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Solvent
Substance (usually liquid) doing the dissolving
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Solubility
Maximum quantity of a substance that will dissolve in a solvent at a given temperature
106
Precipitate
Solid substances formed from reactions in solution
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Structural formula
The illustration of a dash between bonding atoms
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Valence electrons
Bind in a covalent bond
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Orbital
Specific volume of space in which an electron of certain energy is likely to be found
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Valence orbitals
The volumes of space that can be occupied by electrons in an atom's highest energy level
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Bonding electron
An electron shared with another atom
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Lone pair
Two electrons occupying the same orbital
113
Octet rule
Energy levels above the first four contain orbitals, that is, eight electrons maximum. The noble gases have this valence electronic structure; their lack of reactivity indicates that a structure with eight electrons filling a valence level is very stable
114
Lewis symbol
The valence electrons, which do not change, are shown as dots around the central symbol, with the entire diagram showing (for an atom) a net charge of zero
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Covalent bond
The simultaneous attraction of two nuclei for a shared pair of bonding electrons
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Ionic bond
The attraction between any specific cation and any specific anion
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Bonding capacity
The maximum number of single covalent bonds that an atom can form
118
Coordinate covalent bond
A covalent bond in which one of the atoms donates both electrons
119
Stereochemistry
The study of the 3D spatial configuration of molecules and how this affects their reactions.
120
VSEPR Theory
The valence-shell-electron-pair-repulsion theory
121
Nonpolar covalent bond
If the bonded atoms have the same electronegativity
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Polar covalent bond
If the bonded atoms have different electronegativities
123
Bond dipole
The charge separation that occurs when the electronegativity difference of two bonded atoms shifts the shared electrons, making one end of the bond partially positive and the other partially negative
124
London force
The more electrons a molecule has, the more easily momentary dipoles will form, and the greater effect of the London force sill be.
Note: London force is necessarily present between all molecules, whether or not any other types of attractions are present.
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Dipole-dipole force
Attraction between dipoles
126
Pressure
Force per unit area
127
Atmospheric pressure
Force per unit area exerted by air on all objects
128
STP
Standard temperature and pressure (0ºC, 101.325 kPa)
129
SATP
Standard ambient temperature and pressure 25ºC and 100 kPa
130
Boyle's Law
As the pressure on a gas increases, the volume of the gas decreases proportionally, provided that the temperature and chemical amount of gas remain constant.
(P1V1) (2P1, 1/2V1) (4P1, 1/3V1) etc PV=K
131
Absolute zero
The lowest possible temperature of a gas (-273ºC)
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Absolute/Kelvin Temperature Scale
Absolute zero (-273ºC) = Zero Kelvin (0ºK)
133
Charles' Law
As the temperature of a gas increases, the volume increases proportionally, provided that the pressure and chemical amount of a gas remain constant.
V1/T1 = V2/T2
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Combined Gas Law
The product of the pressure and volume of a gas sample is proportional to its absolute temperature in kelvin: PV=kT
P1V1/T1 = P2V2/T2
135
Explain the kinetic molecular theory in brief
q smallest particles (ie. atoms, molecules, ions) are in constant, random motion
q the higher the temp., the faster the motion (ie. the larger the kinetic energy)
q motion stops (ie. kinetic energy is zero) at absolute zero or 0 Kelvin
136
The law of combining volumes
When measured at the same temperature and pressure, volumes of gaseous reactants and products of chemical reactions are always in simple ratios of whole numbers.
137
Avogadro's theory
Equal volumes of gasses at the same temperature and pressure contain equal numbers of molecules.
138
Molar volume
The volume that one mole of a gas occupies at a specified temperature and pressure
139
The molar volume of a gas at STP
22.4 L/mol
140
The molar volume of gas at SATP
24.8 L/mol
141
Ideal gas law
PV = nRT
142
Universal gas constant
The constant, R in the ideal gas law
Its value can be obtained by substituting STP (or SATP) conditions for one mole of an ideal gas into the ideal gas law and solving for R.
8.314 L·kPa/mol·K
143
Solution
A homogeneous mixture of two or more substances
144
Solvent
A substance present in larger quantity within a solution
145
Solute
A substance present in smaller quantity within a solution; dissolved within the solvent
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Electrolytes
Aqueous solutions that conduct electricity
147
Non-electrolytes
Aqueous solutions that do not conduct electricity
148
Dissociation
The separation of ions that occurs when an ionic compound dissolves in water
149
Ionization
The process by which a neutral atom or molecule is converted to an ion.
150
Stock ssolution
An initial, usually concentrated, solution from which samples are taken for a dilution
