Chemistry Final

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Terms in this set (...)

Organic Chemistry
The study of compounds that primarily contain carbon & hydrogen
Inorganic Chemistry
The study of compounds that generally do not contain carbon
Biochemistry
The study of the chemical makeup & processes in organisms
Analytical Chemistry
The study of the chemical makeup of matter
Physical Chemistry
The study of the mechanisms, rates, & energy transfers in chemical reactions
Pure Chemistry
The pursuit of chemical knowledge for its own sake
Applied Chemistry
Research that is directed toward a practical, everyday use
Energy (how it can be applied)
Conserving energy (ex: development of insulation), using energy (ex: refining fossil fuels like petroleum, coal, or natural gas & developing alternative fuels like biodiesel), & storing energy (ex: battery development)
Medicine (how it can be applied)
Making & researching the drugs themselves, making the materials used in medical procedures (ex: artificial hips & prosthetics), & biotechnology (ex: putting plankton genes in cloned cats to make them glow in the dark)
Environment (how it can be applied)
Determining the makeup of the environment, identifying pollutants (ex: lead in paint & gas) & preventing pollution (ex: changing formulas of paint & gas)
Universe (how it can be applied)
Analyze data brought back to Earth (ex: moon rocks) & analyze data from afar (ex: data from Mars rovers or light from stars)
Observation
Any information gained through the senses
Hypothesis
A proposed explanation for an observation; usually an "If..., then..." statement
Experiment
Procedure designed to test the hypothesis
Results/Conclusion
Measurements & observations from the experiment & the conclusion drawn from them
Theory
A well-tested explanation for a broad set of observations
Scientific Law
A concise statement that summarizes the results of many observations and experiments
Independent Variable
The variable in an experiment that is manipulated
Dependent Variable
The variable in an experiment that responds to the independent variable; it is the one that is observed & measured
Constant
Factors in an experiment that are not allowed to change
Control
The group in an experiment to which everything is compared; it is generally not exposed to the independent variable
General Problem
Analyze & solve; or develop a plan & implement the plan
Numerical Problem
Analyze, solve, & evaluate (or check)
Accuracy
Measure of how close a measurement is to the actual value
Precision
Measure of how close together a set of measurements is
8.67x10^5 (put into standard notation)
867000
0.070020 (put into scientific notation)
7.0020x10^-2
10.32 + 124.678 + 0.9129 =
135.91
Sigfigs: 4
8.73 + 15.4 + 19 =
43
Sigfigs: 2
8.342 x 2.22 =
18.5
Sigfigs: 3
8,400 ÷ 12.5 =
670
Sigfigs: 2
Weight
Force with which gravity pulls on an object
Mass
The amount of matter in an object
SI unit of length
meter (m)
SI unit of mass
kilogram (kg)
SI unit of time
second (s)
SI unit of temperature
Kelvin (K)
SI unit of amount
mole (mol)
SI unit of volume
cubic meter (m3)
SI unit of energy
joule (J)
How many Kelvin are in 127°C?
127°C + 273 = 400. K
How many degrees Celsius are in 100. K?
100. K - 273 = -173°C
Convert 0.6979 mg to kg
...
The density of dry air at 25°C is 1.19x10-3 g/cm3. What is the volume of 50.0 g of air in cm3?
...
Gas
Indefinite shape
Indefinite volume
Compressible
Particles spread out
Relatively high kinetic energy
Liquid
Indefinite shape
Definite volume
Not easily compressible
Particles close together
Intermediate kinetic energy
Solid
Definite shape
Definite volume
Not easily compressible
Particles close together
Relatively low kinetic energy
Freezing
Change of a liquid to a solid
Melting
Change of a solid to a liquid
Vaporization
Change of a liquid to a gas
Condensation
Change of a gas to a liquid
Sublimation
Change of a solid to a gas without becoming a liquid
Deposition
Change of a gas to a solid without becoming a liquid
Physical Property
Property that can be observed or measured without changing the identity/composition of the substance
Chemical Property
Property that can only be observed or measured by changing the identity/composition of a substance; ability to undergo specific chemical changes
Intensive Property
Property that depends only on the identity/composition of the substance
Extensive Property
Property that depends on the amount of the substance that is present
Physical Change
Change that only alters some properties of a substance, but not the identity/composition
Chemical Change
Change that results in the formation of a substance other than the original substance
Pure Substance
Matter that has a definite & fixed composition
Mixture
Physical blend of 2 or more substances; has variable composition
Homogeneous Mixture
Mixture in which the composition appears to be uniform
Heterogeneous Mixture
Mixture in which the composition does not appear to be uniform
Filtration
Separation of a solid from a liquid by passing the mixture through a filter; heterogeneous mixtures
Distillation
Separation based on differences in boiling points; homogeneous or heterogeneous mixtures
Decanting
Separation by pouring the top layer off of a mixture; heterogeneous mixtures
Solution
Homogeneous mixture
Colloid
Heterogeneous mixture in which the particles can't be seen with the naked eye, settle more slowly & exhibit the Tyndall effect
Suspension
Heterogeneous mixture in which the particles settle quickly to the bottom
Element
Simplest form of matter with a unique set of properties
Compound
Pure substance containing 2 or more elements chemically combined in a fixed ratio
Reactants
Substances present at the beginning of a reaction; written on the left side of the arrow in a chemical equation
Products
Substances present at the end of a reaction; written on the right side of the arrow in a chemical equation
Products 4 pieces of evidence that a chemical reaction has taken place
Transfer of energy
Color change
Formation of a gas
Formation of a precipitate
Law of Conservation of Matter
In any physical change or chemical reaction, matter is not created or destroyed. Due to this, the mass of the reactants & products of every chemical reaction are equal to each other.
Atoms
Smallest particle of an element that retains the element's unique properties
Who proposed that atoms make up all matter and introduced the term "Atom"
Democritus
Daltons Atomic Theory
All elements are made up of tiny, indestructible particles called atoms.
All atoms of the same element are identical. Atoms of different elements are different
Atoms can be physically mixed together or chemically combined in fixed, whole number ratios
Chemical reactions happen when atoms are joined, separated, or rearranged. Atoms of one element are not changed into atoms of another element in a chemical reaction.
What's used to observe atoms
Scanning tunneling electron microscope
Electron
Properties: negative charge, relatively small mass (1/1840 of the mass of a proton)
Location: outside the nucleus
Discoverer: J.J Thomson
Proton
Properties: positive charge, equal in mass to the neutron
Location: nucleus
Discoverer: Ernest Rutherford
Neutron
Properties: no charge (neutral), equal in mass to the proton
Location: nucleus
Discoverer: James Chadwick
Rutherford's Experiment
Gold foil experiment (aimed a beam of alpha particles at a thin sheet of gold foil with a fluorescent screen around it to record alpha particle impacts)
Rutherford's Results
Most alpha particles went straight through, but some were deflected & some were reflected
Rutherford's Conclusion
The atom is mostly empty space; there is a small, centrally located nucleus where all the positive charge & most of the mass are found; the electrons are located around the nucleus
How to find protons
Equal to the atomic number on the periodic table
How to find electrons
If the atom is neutral, equal to the atomic number on the periodic table
How to find neutrons
Subtract the atomic number from the mass number
Mass Number
Sum of the protons & neutrons in the nucleus of the atom
Atomic Mass
Weighted average of the isotopes of the element
How to calculate mass number
Add the number of protons to the number of neutrons
Groups
Vertical columns on the periodic table; elements within the same group have similar properties
Periods
Horizontal rows on the periodic table; elements within the same period have differing properties
Who developed the first widely accepted Periodic Table
Dmitri Mendeleev
How elements were arranged in early Periodic Tables
In order of increasing atomic mass, grouped by similar properties
How elements were arranged in modern Periodic Tables
In order of increasing atomic number, grouped by similar properties
Metals
Lustrous, malleable, ductile, good conductors of heat & electricity, almost entirely solids at room temperature
Nonmetals
Dull, brittle, poor conductors of heat & electricity, mostly gases at room temperature
Metalloids
Some properties of metals, some properties of nonmetals
Information that can found in the boxes on the Periodic Table
Most common information is atomic number, atomic mass, element name, & element symbol, but more information can be found, such as state of matter, electron configuration, etc.
Group 1
Alkali metals (except hydrogen): Li, Na, K, Rb, Cs, Fr
Group 2
Alkaline earth metals: Be, Mg, Ca, Sr, Ba, Ra
Group 16
Chalcogens: O, S, Se, Te, Po
Group 17
Halogens: F, Cl, Br, I, At
Group 18
Noble gases: He, Ne, Ar, Kr, Xe, Rn
Representative Elements
Groups 1 & 2, 13-18; s & p blocks; determine the valence electrons by group number (equal to the group number in 1 & 2, equal to the group number minus 10 in 13-18, except He, which has 2)
Transition Metals
Groups 3-12; d block; most have 2 valence electrons, but some only have 1
Inner Transition Metals
Lanthanides & actinides; f block; most have 2 valence electrons, but some only have 1
S block
Groups 1 & 2 & He
P block
Groups 13-18, except He
D block
Groups 3-12
F block
lanthanides & actinides
Atomic Size
Increases from right to left in a period & top to bottom in a group (down & left)
Electronegativity
Increases from left to right in a period & bottom to top in a group (up & right)
Ionization Energy
Increases from left to right in a period & bottom to top in a group (up & right)
Ionic Size
Increases from right to left in a period (for the most part - anions are larger than cations, though) & top to bottom in a group (down & left, but anions are larger than cations)
Ions
Atoms or groups of atoms with positive or negative charge
Anions
ions with a negative charge
Cations
ions with a positive charge
Nuclear Charge
Charge of the nucleus; responsible for the changes of trends in the periods (the horizontal changes)
Electron Shielding
Number of electron layers between the valence electrons & nucleus; responsible for the changes of trends in the groups (the vertical changes)
Rutherford's Model
Nucleus in the center & the electrons distributed all around it
Bohr's Model
Nucleus in the center & the electrons distributed around it in set orbits or energy levels; energy levels get closer together as they get farther from the nucleus & electrons can change energy levels
Quantum Mechanical Model
Nucleus in the center & the electrons distributed around it in orbitals rather than set paths; energy levels are still present though
How many orbitals and the shapes of orbitals in the s sub level
1 orbital, spherical
How many orbitals and the shapes of orbitals in the p sub level
3 orbitals, 8-shaped
How many orbitals and the shapes of orbitals in the d sub level
5 orbitals, clover leaf-shaped
How many orbitals and the shapes of orbitals in the f sub level
7 orbitals, complex shapes
Aufbau Principle
Electrons fill the lowest energy levels before filling higher ones
Pauli Exclusion Principle
There can be a maximum of 2 electrons in a given orbital & they must spin in opposite directions
Hund's Rule
Each orbital of a sublevel will receive one electron before any of them receive 2 & electrons in different orbitals spin in the same direction
Exceptions to the Aufbau Principle
Cr, Mo, Cu, Ag, Au
Relationship between wavelength & frequency
Inversely proportional
Relationship between frequency & energy
Directly proportional
Full electron configuration for K
1s22s22p63s23p64s1
Abbreviated electron configuration for Sr
[Kr] 5s2
A radio station broadcasts at a frequency of 1.15x106 Hz. What is the wavelength of the waves coming from the station?
c = λ ν
3.00x108 m/s = λ x 1.15x10^6 Hz
λ = 261 m
What is the energy contained in x-rays with a frequency of 3.12x1018 Hz?
E = h ν
E = 6.626x10^-34 Js x 3.12x10^18 Hz
E = 2.07x10^-15 J
What is the energy contained in radiation with a wavelength of 7.82x10-7 m?
E = h c/λ
E = 3.00x10^8 m/s x 6.626x10^-34/Js
7.82x10-7 m
E = 2.54x10^-19 J
Classical Mechanics
Used to measure & describe the motion of objects larger than atoms.
Quantum Mechanics
Used to measure & describe the motion of objects smaller than atoms. Also, these objects behave as waves as well as particles in quantum mechanics.
Which elements forms Cations
Metals
Which elements form Anions
Non Metals
How do Cations form
Loosing electrons
How do Anions form
Gaining electrons
Octet Rule
When elements form compounds, they tend to achieve the same electron configuration of a noble gas. They tend to have 8 valence electrons in a compound, regardless of how many they have when alone.
What charge Cs forms and the name of the ion
1+, cesium ion
Write chemical formula for ionic compound for Na & O
Na2O
Physical properties of ionic compounds
Crystalline solid at room temperature
High melting point
Conduct electricity when melted or dissolved
Charge: 0; no charge; neutral
How electrons can be modeled
Sea of electrons
Alloy
Mixture of 2 or more metals, generally, although other classes of elements can be present
Alloy importance
Alloys generally have at least one property that is superior to that of the pure metal
Examples of alloys
Bronze, sterling silver, white gold, pewter
Coordination Number
The number of ions of opposite charge immediately surrounding a given ion in an ionic compound or the number of atoms immediately surrounding a given atom in a metal
Coordination Number for Simple cubic arrangement
6
Coordination Number for Body-centered cubic arrangement
8
Coordination Number for Face-centered cubic arrangement
12
Coordination Number for Hexagonal close packed arrangement
12
Differences between the properties of ionic & molecular compounds.
Ionic compounds have ionic bonds (from gain & loss of electrons), molecular compounds have covalent bonds (from sharing electrons)
Ionic compounds have high melting points, molecular compounds usually have low melting points Ionic compounds are solids, molecular compounds can be any state of matter
Covalent Bonds
Bonds that hold atoms together by sharing electrons
Coordinate Covalent Bonds
Covalent bond in which both shared electrons come from the same atom
Network Solid
Solids in which all of the atoms are covalently bonded to one another