Section 1
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chemistry
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Cards (114)
Section 1
(50 cards)
chemistry
study of matter, its properties, and its changes
composition vs. structure
comp= types of atoms matter contains strx.= arrangement of atoms
solutions/homogenous mixtures
-uniform throughout, can be solid, liquid, or gas -can be one substance dissolved in another -ex. air, salt dissolved in water) -separate by distillation or chromatography
micro
10^-6
giga
energy
-difference between two states of same substance is energy -capacity to do work or transfer heat, doesn't have mass -Joule= 1kg-m^2/s^2 -4.184 J=1 cal -heat released to form 1 gram of water =16kJ -cal: raises 1g water 1*C -1Cal=1000cal=1kcal
pico
chemical change/reaction
-processes in which a substance is transformed into a chemically different substance -ex. formation of water
mixtures
-combinations of two or more substances i which each substance retains its chemical identity -composition varies -components: make up mixture
law of constant composition/law of definite proportions
-Jospeph Louis Proust (French) -the elemental composition of a compound is always the same
intensive properties
-does not depend on amount of sample -ex. temp, melting point, density -used to identify
atom
smallest representative particle of an element
zepto
10^-21
centi
element
substance that cannot be decomposed into simpler substances -118 known -background for understanding properties at atomic level -1 kind of atom makes up an element -denoted using chemical symbols from English or foreign name -arranged in periodic table
uses of chemistry
energy, biochemistry, technology, medicine, safety, industry -make new types of matter -measure properties of matter -develop models to explain and/or predict properties of matter -used by large organizations (ex. NIH)
Ira Ramsen
- observed effects of nitric acid on pennies
macroscopic
ordinary-sized
gas
-aka vapor -no fixed volume or shape, fills container -compressible -expands -high speed molecules, repeat collisions, far apart unless compressed
extensive properties
-depends on around of sample -ex. mass, volume -gives amount
peta
heterogenous mixtures
-mixtures varying in texture, appearance, composition, properties -ex. rock, wood, granite -can be separated by color, magnetic attraction, filtration, and ability to dissolve
milli
kinetic energy
-the energy that an object possesses by virtue of its motion m= mass v=velocity -increases with velocity/speed or mass -increases with heat -transfer of heat is transfer of KE
work
the energy transferred when a force exerted on an object cases a displacement of that object - (force times distance) -Force=any push or pull on object
compounds
-substances composed of two or more elements/2+ kinds of atoms -ex. water formed from hydrogen gas burning in oxygen (hydrogen lighter than oxygen but occupies more volume) -properties of compound different than individual properties of elements -natural and laboratory compounds have same properties if they are the same compound
property
characteristic that allows us to recognize particular type of matter and distinguish from other types -affected by even the slightest differences in composition or structure
theory
-a tested model or explanation that has predict powers and that accounts for all available observations (checked with others) -explanation -ex. theory of relativity
tera
mega
10^6
microscopic
atoms and molecules
physical properties
-properties that can be measured without changing the composition of a substance (ex. color, freezing point, melting point, boiling point, odor, density, hardness)
physical change
-changes in appearance (such as phase) that occur with no change in chemical composition
molecule
chemical combo of 2+ atoms (represented by colored spheres)
kilo
states of matter
-can be changed by temp and pressure
nano
deci
10^-1
atto
liquid
-distinct volume -(slightly) not compressible -closely packed molecules that slide over one another (pour) -fast molecules
femto
chemical properties
properties that describe the way a substance may change, or react to form other substances (ex. flammability)
solid
-definite shape and volume -not compressible -tight, defined arrangement molecules -very little movement
pure substances
matter that has a fixed composition and distinct properties; does not vary by sample -elements or compounds -not the usual form of matter
potential energy
- energy by virtue of an object's position relative to other objects, stored energy that arises from attractions and repulsions -can be converted to KE and vice versa
scientific law
-a statement of what is always observed to happen, tot the best of our knowledge -statement -ex. law of conservation of mass
electrostatic potential energy
arises from interactions between charged particles
matter
anything that occupies space ands mass, physical material of universe
scientific method
collect information, form hypothesis (model or tentative explanation of a series of observations), test hypothesis, form theory, repeatedly test theory
heat
the energy that causes the temp of an object to increase; flow of energy from body at high heat to body at lower heat
Section 2
(50 cards)
JJ Thomson
- cathode rays are same regardless of material, must have common negative particle ELECTRON -calculated approximate charge of electron -used a cathode ray that included charged plates and magnets -created plum pudding model
cathode rays
streams of electrons that are produced when a high voltage is applied to electrodes in an evacuated tube (originate at negative electrode and travel to positive); invisible but cause certain materials to fluoresce
radioactivity
radioactive; the spontaneous disintegration of an unstable atomic nucleus with accompanying emission of radiation
temperature
-measure of heat flow -celcius: freezes at 0 boils at 100 -Farenheit:freezes at 32 and boils at 212 -Kelvin:0=-273*C
quantitative
associated with numbers, measured property, must be accompanied by units
atoms
-smallest representative particle of an element -Democritus:tiny, indivisible particles -Plato, Aristotle:said no to indivisible particles -1-5 Angstrom diameter range
atomic mass units
amu; a unit based on the value of exactly 12 amu for the mass of the isotope of carbon that has 6 protons and 6 neutrons in the nucleus (= 1.66054*10^-24)
atomic weight
the sum of the masses of isotopes times their relative abundances; average atomic mass
group/family
vertical columns containing elements with similar properties
molecular formula
chemical formula that indicates actual number of atoms of each element in one molecule of a substance (can be used to find empirical formula)
James Chadwick
discovered neutrons in the nucleus in 1932
absolute zero
temp where all thermal motion ceases 0K
SI Units
-French, 1960, 7 total -length:meter:m -mass:kilogram:kg -temp:kelvin:K -time:second:s -amount:mole:mol -electric current:ampere:A or amp -luminous intensity:candela:cd also recognized -Power:watt:W -energy:joule:J -joined with prefixes
alpha
-bent by electric field -fast-moving electrically charged particles -positive charge, charge of +2
density and volume
density: mass/volume ex. water is 1.00 g/mL TEMP DEPENDENT: ASSUME 25*C IF NOT GIVEN volume: length cubed 1mL=1cc=1cm^3 -variable volumes measured with syringe, burette, or graduated cylinder -pipette: delivers specific volume -volumetric flask: holds specific volume
ions
charged particle caused by loss or gain of electrons -easily predict charge by looking at group on periodic table
chemical energy
released when bonds between atoms form
nuclear model
model of the atom with small and extremely dense nucleus containing most of the mass, and with electrons in the space outside the nucleus
diatomic molecule
molecules made of two atoms (have no fear of ice cold beer)
atomic number
number of protons an atom possess (indicated by subscript)
dimensional analysis
-method of problem solving in which units are multiplied together or divided into each other along with numerical values
subatomic particles
protons, neutrons, electrons -protons: positive, inside nucleus, 1.0073 amu, +1 -electron:-1, negative, -1.60210^-19 Coulombs, 5.48610^-4 amu -neutron: neutral, 1.0087 amu -also quarks, leptons, and bosons
accuracy
-a measure of how closely individual measurements agree with the correct or true value
precision
the closeness of agreement among several measurements of the same quantity -described in standard deviation: variation from average
mass
measure of amount of material in object
isotopes
Atoms of the same element that have different numbers of neutrons
law of multiple proportions
two elements can combine to form more than one compound
nucleus
the very small, very dense, positively charged portion of an atom; it is composed of protons and neutrons
sig figs
-uncertain=able to be estimated -the digits that indicate the precision with which a measurement is made -greater# of sig figs=greater precision -exponential notation used to clarify if zeros are significant -addition/subtraction:# of decimal places as measurement with fewest decimal places (convert to same unit first) -multiplication/division: same as# with fewest sig figs
John Dalton
1)every element made of atoms 2)all atoms of same element identical 3)law of conservation of mass 4)compounds formed by 2+elements (law of constant composition as well) -had to assume existence of ions
Robert Milikan
oil drop experiment: small drops of oil fall between electrically charged plates, calculated negative charge by seeing how voltage affected rate of fall -used this charge to calculate the electron's mass
metals, metalloids, nonmetals, alloys
-metals: solids at room temp (except mercury), conduct heat, lustrous -metalloids:elements that lie along the diagonal line separating metals from nonmetals -nonmetals:in upper right corner of periodic table, different from metal properties -alloy: combination of metal
basic forces
gravitational, electromagnetic, strong nuclear force, weak nuclear force
derived unit
-an SI unit obtained by the multiplication or division of one or more of the SI base units -ex. speed=m/s
exact vs. inexact
exact:counting #s or defined values, value equivalent to #1 in any conversion factor, infinite number of sig figs inexact:measured values
molecular form
two or more of the same type of atom bound together -ex. diatomic elements and oxygen
empirical formula
chemical formula that shows the kinds of atoms and their relative numbers in a substance in the smallest possible whole number ratios -only form for ionic compounds
mass number
# of protons + # of neutrons (indicated by superscript)
Ernest Rutherford
-revealed three different types of radiation, discovered nucleus and protons Gold Foil Experiment: studied alpha particle passing through gold and recorded deflection angles -concluded that the nucleus must be small and circles by electrons
metric system
system of measurement used in science and in most countries, developed in France
structural formulas
SHOWS HOW ATOMS IN MOLECULE ARE BONDED -ball and stick:atoms are spheres and bonds are sticks, most accurate for angles -perspective: use wedges and dashed lines to create 3D on paper -space-filling: show molecules if atoms were scaled up
mass spectrometer
most accurate way to determine atomic weights, reveals mass spectrum, mass of ions, and fractional abundances of isotopes
conversion factors
-a fraction whose numerator and denominator are the same quantity expressed in different units; desired unit on top and given unit on bottom -keep track of units and prefixes -if using volume, must be cubed -density: a conversion factor between mass and volume
gamma
-not bent by electric field -high energy, electromagnetic -no charge or particles
beta
-bent by electric field -fast-moving electrically charged particles -high speed electrons that are considered radioactive equivalent of cathode ray -charge of -1
Henri Becquerel and Marie Curie
-compound of uranium spontaneously emit high-energy radiation -MC: concluded radioactivity was from uranium atoms, discovered polonium and radium
periodic table
-1869 -1A is alkali metals -2A is alkaline earths -7A is halogens -8A is noble gases (nonreactive) -arranged by increasing atomic number -6A is chalcogens
period
horizontal rows
electronic charge
the negative charge carried by an electron
angstroms
equal to 10^-10m
Section 3
(14 cards)